Samacheer Kalvi Class 10 Science Solutions Chapter 17 Reproduction in Plants and Animals

I. Choose the correct answer:

 

Question 1. The plant which propagates with the help of its leaves is:
(a) Onion
(b) Neem
(c) Ginger
(d) Bryophyllum
Answer: (d) Bryophyllum
In simple words: Bryophyllum plants are unique because new plants can grow directly from their leaves, especially from the notches along the leaf edges. This is a common way plants reproduce without seeds.

🎯 Exam Tip: Remember specific examples of plants and their propagation methods, as these are often tested.

 

Question 2. Asexual reproduction takes place through budding in _______.
(a) Amoeba
(b) Yeast
(c) Plasmodium
(d) Bacteria
Answer: (b) Yeast
In simple words: Budding is a type of asexual reproduction where a new organism develops from an outgrowth or bud due to cell division at one particular site. Yeast is a well-known example of an organism that reproduces this way, forming smaller daughter cells from a parent cell.

🎯 Exam Tip: Distinguish between different types of asexual reproduction (like budding, fission, fragmentation) and their specific examples.

 

Question 3. Syngamy results in the formation of:
(a) Zoospores
(b) Conidia
(c) Zygote
(d) Chlamydospores
Answer: (c) Zygote
In simple words: Syngamy is when two gametes (sex cells) fuse together, and this fusion always creates a zygote. This zygote is the very first cell of a new organism.

🎯 Exam Tip: Understand that syngamy refers specifically to the fusion of gametes, leading directly to zygote formation, which is a key step in sexual reproduction.

 

Question 4. The essential parts of a flower are _______.
(a) Calyx and Androecium
(b) Corolla and Gynoecium
(c) Androecium and Gynoecium
Answer: (c) Androecium and Gynoecium
In simple words: The androecium contains the male reproductive parts, and the gynoecium contains the female reproductive parts of a flower. These two parts are crucial for the flower to make seeds.

🎯 Exam Tip: Remember that "essential" parts are directly involved in reproduction, while "non-essential" parts (like sepals and petals) are for protection and attraction.

 

Question 5. Anemophilous flowers have:
(a) Sessile stigma
(b) Small smooth stigma
(c) Colored flower
(d) Large feathery stigma
Answer: (d) Large feathery stigma
In simple words: Anemophilous flowers rely on wind to carry their pollen. A large, feathery stigma helps these flowers catch pollen grains floating in the air very easily.

🎯 Exam Tip: Recognize the adaptations of wind-pollinated (anemophilous) flowers, such as reduced petals, no scent, and large stigmas, which distinguish them from insect-pollinated flowers.

 

Question 6. Male gametes in angiosperms are formed by the division of _______.
(a) Generative cell
(b) Vegetative cell
(c) Microspore mother cell
(d) Microspore
Answer: (a) Generative cell
In simple words: In flowering plants, the generative cell inside the pollen grain divides to form the two male gametes needed for fertilization. This ensures that the genetic material is ready for reproduction.

🎯 Exam Tip: Trace the complete development of male gametes in angiosperms, from microspore to generative cell division, to understand the process fully.

 

Question 7. What is true of gametes?
(a) They are diploid
(b) They give rise to gonads
(c) They produce hormones
(d) They are formed from gonads
Answer: (d) They are formed from gonads
In simple words: Gametes are sex cells, like sperm and egg, which are produced in specialized organs called gonads. For example, sperm are made in testes and eggs in ovaries.

🎯 Exam Tip: Remember that gametes are typically haploid (have half the number of chromosomes) and are produced by meiosis in the gonads.

 

Question 8. A single highly coiled tube where sperms are stored, get concentrated and mature is known as _______.
(a) Epididymis
(b) Vasa efferentia
(c) Vas deferens
(d) Seminiferous tubules
Answer: (d) Seminiferous tubules
In simple words: The seminiferous tubules are tiny tubes inside the testes where sperm are made and begin their journey to mature. They act like a nursery for sperm production.

🎯 Exam Tip: Understand the pathway of sperm development and maturation, knowing the specific role of each structure in the male reproductive system.

 

Question 9. The large elongated cells that provide nutrition to developing sperms are:
(a) Primary germ cells
(b) Sertoli cells
(c) Leydig cells
(d) Spermatogonia
Answer: (b) Sertoli cells
In simple words: Sertoli cells are like "nurse cells" that support and feed the developing sperm cells in the testes. They are essential for proper sperm growth.

🎯 Exam Tip: Differentiate between the functions of Sertoli cells (nourishment) and Leydig cells (hormone production) in the testes.

 

Question 10. Estrogen is secreted by _______.
(a) Anterior pituitary
(b) Primary follicle
(c) Graafian follicle
(d) Corpus luteum
Answer: (b) Primary follicle
In simple words: Estrogen is mainly made by the primary follicles in the ovaries as they grow. This hormone plays a big role in female sexual development.

🎯 Exam Tip: Be aware of the roles of different ovarian structures in producing female hormones and their timing during the menstrual cycle.

 

Question 11. Which one of the following is an IUCD?
(a) Copper - T
(b) Oral pills
(c) Diaphragm
(d) Tubectomy
Answer: (a) Copper - T
In simple words: An IUCD, like Copper-T, is a small device placed inside the uterus to prevent pregnancy. It works for a long time.

🎯 Exam Tip: Know the different types of contraceptive methods and their mechanisms, identifying which category each method falls into (e.g., barrier, hormonal, IUCD, surgical).

 

II. Fill in the blanks:
Answer:
1. The embryo sac in a typical dicot at the time of fertilization is Double fertilization.
2. After fertilization the ovary develops into Fruits.
3. Pianaria reproduces asexually by Regeneration.
4. Fertilization is Internal in humans.
5. The implantation of the embryo occurs at about 6 to 7 day of fertilization.
6. Colostrum is the first secretion from the mammary gland after child birth.
7. Prolactin is a hormone produced by Anterior pituitary.
In simple words: These terms describe key stages and processes in plant and human reproduction and development. Knowing them helps understand how new life begins and grows.

🎯 Exam Tip: Pay close attention to definitions and specific numbers or locations in biological processes, as these are common fill-in-the-blank questions.

 

III. Match the following

Answer:
A. (ii) Amoeba
B. (iii) Yeast
C. (i) Spirogyra
In simple words: This match correctly links different ways organisms reproduce asexually with specific examples. Fission involves splitting into two, budding involves growing an outgrowth, and fragmentation involves breaking into pieces.

🎯 Exam Tip: Learn the definitions and classic examples for each type of asexual reproduction to accurately match them.

 

Answer:
A. (iii) Delivery of baby from uterus
B. (i) Duration between pregnancy and birth
C. (iv) Release of egg from Graafian follicle
D. (ii) Attachment of zygote to endometrium
In simple words: This matching exercise defines important terms related to human reproduction. It clarifies when an egg is released, how a baby is born, how a zygote attaches, and the length of pregnancy.

🎯 Exam Tip: Accurately understanding and defining key terms in human reproduction is crucial for answering questions on this topic.

 

IV. State whether the following statements are True or False. Correct the false statement.

 

Question 1. Stalk of the ovule is called pedicle.
Answer: False - The stalk of the ovule is called Funiculus. The pedicle is the stalk of a single flower.
In simple words: The ovule has a small stalk that connects it to the ovary wall, and this specific stalk is named the funiculus, not the pedicle. It helps the ovule receive nutrients.

🎯 Exam Tip: Be precise with anatomical terms; "pedicle" and "funiculus" refer to different structures.

 

Question 2. Seeds are the product of asexual reproduction.
Answer: False – Seeds are the product of sexual reproduction. Seeds are formed after fertilization, where male and female gametes fuse.
In simple words: Seeds are formed when a male and female part of a plant join together. This means it is a part of sexual reproduction, not asexual.

🎯 Exam Tip: Understand that sexual reproduction involves the fusion of gametes and results in genetic variation, while asexual reproduction produces genetically identical offspring.

 

Question 3. Budding reproduces asexually by means of multiple fission.
Answer: False - Budding reproduces asexually by means of forming an outgrowth or bud, not multiple fission. Multiple fission involves an organism splitting into many daughter cells.
In simple words: Budding is when a small new part grows out of the parent and then breaks off to become a new organism, which is different from multiple fission where one cell splits into many.

🎯 Exam Tip: Clearly differentiate between budding (outgrowth), binary fission (two equal parts), and multiple fission (many parts) as modes of asexual reproduction.

 

Question 4. The part of the pistil which serves as a receptive structure or the pollen is called as style.
Answer: False – The part of the pistil which serves as a receptive structure for the pollen is called the stigma. The style is the stalk connecting the stigma to the ovary.
In simple words: The sticky top part of the pistil that catches pollen is called the stigma. The style is just the stalk that holds the stigma up.

🎯 Exam Tip: Remember the three main parts of the pistil (stigma, style, ovary) and their specific functions in reproduction.

 

Question 5. Insect pollinated flowers are characterized by dry and smooth pollen.
Answer: False – Wind pollinated flowers are characterized by dry and smooth pollen. Insect pollinated flowers usually have sticky or spiny pollen to attach to insects.
In simple words: Flowers pollinated by wind have light, smooth pollen that can fly easily in the air. Flowers pollinated by insects have pollen that sticks to them.

🎯 Exam Tip: Compare and contrast the characteristics of wind-pollinated versus insect-pollinated flowers, focusing on pollen type, stigma, petals, and scent.

 

Question 6. Sex organs produce gametes which are diploid.
Answer: False – Sex organs produce gametes which are haploid. Gametes have half the number of chromosomes of a normal body cell.
In simple words: Gametes are special cells that only have half of the usual genetic material. When two gametes join, they make a new cell with a full set of genetic material.

🎯 Exam Tip: Crucially distinguish between haploid (gametes, n) and diploid (somatic cells, 2n) chromosome numbers, as this is fundamental to genetics.

 

Question 7. LH is secreted by the posterior pituitary.
Answer: False – LH (Luteinizing Hormone) is secreted by the anterior pituitary gland. The posterior pituitary releases ADH and Oxytocin.
In simple words: LH is a hormone that comes from the front part of the pituitary gland in the brain. It's important for reproduction.

🎯 Exam Tip: Know the specific hormones secreted by the anterior and posterior pituitary glands and their respective functions.

 

Question 8. Menstrual cycle ceases during pregnancy.
Answer: True
In simple words: When a woman gets pregnant, her body stops the menstrual cycle. This is because the uterus is busy supporting the growing baby.

🎯 Exam Tip: Understand the hormonal regulation of the menstrual cycle and how pregnancy alters this cycle to maintain the uterine lining.

 

Question 9. Surgical methods of contraception prevent gamete formation.
Answer: True
In simple words: Surgical methods, like tubectomy or vasectomy, block the tubes that carry gametes, effectively preventing their release or meeting. These methods stop gametes from reaching where they need to be for fertilization.

🎯 Exam Tip: While surgical methods prevent the *release* or *meeting* of gametes, they do not necessarily prevent gamete *formation* (spermatogenesis or oogenesis) in the gonads themselves; rather, they block their transport. Be precise in your language for exam answers.

 

Question 10. The increased level of oestrogen and progesterone is responsible for menstruation.
Answer: True
In simple words: Menstruation happens when the levels of estrogen and progesterone drop, which causes the uterine lining to shed. This drop in hormones, not an increase, triggers the menstrual period.

🎯 Exam Tip: Remember that a *decrease* in estrogen and progesterone levels, specifically after the corpus luteum degenerates, triggers menstruation, not an increase.

 

V. Answer in a word or sentence.

 

Question 1. If one pollen grain produces two male gametes, how many pollen grains are needed to fertilize 10 ovules?
Answer: At least 10 pollen grains are required to fertilize 10 ovules. This is because each ovule needs one male gamete for fertilization, and each pollen grain provides two male gametes, one for the egg cell and one for the central cell (triple fusion).
In simple words: You need at least 10 pollen grains for 10 ovules. Each ovule needs one male part to become a seed.

🎯 Exam Tip: In double fertilization, one male gamete fertilizes the egg, and the other fuses with the central cell (polar nuclei); therefore, one pollen grain containing two male gametes is sufficient for one ovule's complete fertilization.

 

Question 2. In which part of the flower germination of pollen grains takes place?
Answer: Pollen grains reach the stigma and begin to germinate there. The stigma is the receptive surface for pollen.
In simple words: Pollen grains land on the sticky top part of the flower, called the stigma, and start to grow there.

🎯 Exam Tip: Remember that pollen grain germination is the first step in successful pollination, leading to the growth of the pollen tube.

 

Question 3. Name two organisms which reproduces through budding.
Answer: Two organisms that reproduce through budding are Yeast and Hydra. These organisms form a small outgrowth that develops into a new individual.
In simple words: Yeast and hydra are two living things that make new copies of themselves by growing a small bud that breaks off.

🎯 Exam Tip: Keep common examples of asexual reproduction methods clear, as they are frequently asked in short answer questions.

 

Question 4. Mention the function of the endosperm.
Answer: The endosperm primarily provides food to the developing embryo in a seed. It is rich in nutrients like starch, proteins, and fats.
In simple words: The endosperm acts like food storage inside a seed. It gives the baby plant the energy it needs to grow.

🎯 Exam Tip: Understand that endosperm development is a unique result of double fertilization in angiosperms, crucial for embryo nourishment.

 

Question 5. Name the hormone responsible for the vigorous contractions of the uterine muscles.
Answer: Oxytocin is the hormone responsible for the vigorous contractions of the uterine muscles. It is released from the posterior pituitary gland.
In simple words: Oxytocin is a hormone that makes the muscles in the uterus squeeze strongly. This helps in childbirth.

🎯 Exam Tip: Link oxytocin specifically with uterine contractions during labor and milk ejection, distinguishing it from other reproductive hormones.

 

Question 6. What is the enzyme present in the acrosome of sperm?
Answer: Hyaluronidase is the enzyme present in the acrosome of sperm. This enzyme helps the sperm to break down the outer layers of the ovum, allowing fertilization.
In simple words: The sperm has a special enzyme called hyaluronidase in its head. This enzyme helps it get inside the egg.

🎯 Exam Tip: Remember that the acrosome reaction, involving hyaluronidase, is a critical step for successful fertilization.

 

Question 7. When is Menstrual Hygiene Day observed?
Answer: Every year, May 28th is observed as Menstrual Hygiene Day. This day aims to raise awareness among girls and women about the importance of maintaining menstrual hygiene for good health.
In simple words: Menstrual Hygiene Day is on May 28th each year. It's a day to teach everyone about keeping clean during periods and why it's important.

🎯 Exam Tip: Be aware of important public health days and their significance, especially those related to hygiene and women's health.

 

Question 8. What is the need for contraception?
Answer: Contraception is needed to prevent unintended pregnancies and to help manage population growth. It allows individuals and couples to make informed choices about family size and spacing.
In simple words: Contraception helps people decide when and if they want to have children. It also helps control how fast the population grows.

🎯 Exam Tip: When discussing the need for contraception, include both individual benefits (family planning, maternal health) and societal benefits (population management).

 

Question 9. Name the part of the human female reproductive system where the following occurs, (a) Fertilization (b) Implantation
Answer:
(a) Fertilization: Occurs in the oviduct, specifically in the ampulla of the fallopian tube.
(b) Implantation: Occurs when the blastocyst attaches to the uterus, specifically the uterine wall (endometrium).
In simple words: Fertilization, where sperm meets egg, happens in the fallopian tube. Implantation, where the early baby attaches to the womb, happens in the uterus.

🎯 Exam Tip: Precisely identify the locations of key events like fertilization and implantation in the female reproductive system.

 

VI. Short Answer Questions

 

Question 1. What will happen if you cut planaria into small fragments?
Answer: If Planaria is cut into small fragments, each fragment will develop into a new, complete individual. This process is called regeneration, which is the ability of an organism to regrow lost body parts or an entire organism from a part.
In simple words: If you cut a Planaria worm into pieces, each piece can grow into a whole new worm. This special ability is called regeneration.

🎯 Exam Tip: Planaria is a classic example for demonstrating regeneration; remember to define regeneration in your answer.

 

Question 2. Why is vegetative propagation practised for growing some type of plants?
Answer: Vegetative propagation is practiced for growing certain plants because it allows for the rapid production of new plants that are genetically identical to the parent. This method is useful for plants that do not produce viable seeds or for quickly multiplying desired plant traits. For example, a detached vegetative part like a root, stem, or leaf can grow into a new plant.
In simple words: People use vegetative propagation to grow plants quickly and make sure the new plants are exactly like the parent. This is good for plants that don't make seeds easily or when you want to keep special plant qualities.

🎯 Exam Tip: Highlight the two main advantages of vegetative propagation: genetic uniformity (cloning) and rapid multiplication, especially for plants with poor seed viability.

 

Question 3. How does binary fission differ from multiple fission?

Answer: The table above explains the key differences between binary fission and multiple fission. Binary fission is a simpler process resulting in two daughter cells, while multiple fission produces many cells, often under protective conditions. Both are forms of asexual reproduction.
In simple words: Binary fission makes two new cells from one, usually when conditions are good. Multiple fission makes many new cells from one, often when conditions are tough and the parent cell is protected.

🎯 Exam Tip: When comparing biological processes, organizing your answer in a table format can effectively highlight the differences and earn full marks.

 

Question 4. Define triple fusion.
Answer: Triple fusion is the process in flowering plants where one male gamete fuses with two polar nuclei within the embryo sac. This fusion leads to the formation of the endosperm, which provides nutrition to the developing embryo.
In simple words: Triple fusion is a special event in plants where one male reproductive cell joins with two other central cells. This makes a nutrient-rich part called the endosperm that feeds the baby plant.

🎯 Exam Tip: Remember that triple fusion is a part of double fertilization, unique to angiosperms, and its product (endosperm) is vital for embryo survival.

 

Question 5. Write the characteristics of insect-pollinated flowers.
Answer: Insect-pollinated flowers have several characteristics that attract insects: 1. They are usually brightly colored, often with attractive patterns or nectar guides, to grab insects' attention. 2. They produce a scent or fragrance to attract insects from a distance. 3. They often have nectar, a sugary fluid, as a reward for visiting insects. 4. Their pollen grains are typically larger, sticky, or spiny, so they can easily adhere to the insect's body.
In simple words: Insect-pollinated flowers are bright, smell nice, and often have a sweet treat (nectar) for insects. Their pollen is also sticky so it can easily attach to the insect.

🎯 Exam Tip: When describing adaptations, always link the characteristic (e.g., bright color) to its function (e.g., attracting insects).

 

Question 6. Name the secondary sex organs in male.
Answer: The secondary sex organs in males include the vas deferens, epididymis, seminal vesicle, prostate gland, and penis. These organs are involved in the transport and storage of sperm, as well as the production of seminal fluid.
In simple words: The secondary sex organs in males are the parts that help carry and store sperm, like the vas deferens, epididymis, and penis, along with glands that make fluid to protect the sperm.

🎯 Exam Tip: Distinguish between primary sex organs (gonads, e.g., testes, which produce gametes and hormones) and secondary sex organs (which aid in gamete transport and storage).

 

Question 7. What is colostrum? How is milk production hormonally regulated?
Answer: Colostrum is the first milk produced by the breasts during the initial 2 to 3 days after childbirth. It is rich in antibodies, providing essential immunity to the newborn. Milk production from the alveoli of the mammary glands is primarily stimulated by prolactin, a hormone secreted by the anterior pituitary gland. Oxytocin also plays a role in milk ejection.
In simple words: Colostrum is the first special milk a mother makes right after birth, full of protective things for the baby. A hormone called prolactin tells the body to make milk.

🎯 Exam Tip: Remember colostrum's importance for infant immunity and the specific role of prolactin in milk production, as distinct from oxytocin's role in milk release.

 

Question 8. How can menstrual hygiene be maintained during menstrual days?
Answer: Maintaining good menstrual hygiene is very important for a woman's overall health during menstrual days. This can be achieved by:

• Sanitary pads or other menstrual products should be changed regularly (every 4-6 hours) to prevent infections caused by microbes and sweat.
• Using warm water to clean the genital area helps to prevent infections and can reduce menstrual cramps.
• Wearing loose-fitting cotton clothing ensures proper airflow around the genitals, which helps prevent moisture buildup and sweating, reducing the risk of irritation and infections.

These practices are crucial for comfort and preventing health issues.
In simple words: To stay clean during periods, always change pads often, wash with warm water, and wear loose clothes. This helps stop germs and keeps you comfortable.

🎯 Exam Tip: Provide practical and clear advice for menstrual hygiene, focusing on preventing infections and maintaining comfort.

 

Question 9. How does developing embryo gets its nourishment inside the mother's body?
Answer: The developing embryo receives its nourishment from the mother's blood through a specialized tissue called the placenta. The placenta forms between the uterine walls and the embryo. It has tiny finger-like projections (villi) on the embryo's side and blood spaces on the mother's side. This structure creates a large surface area for efficient exchange of oxygen, nutrients (like glucose), and waste products between the mother and the embryo, ensuring the embryo's growth and development.
In simple words: The growing baby gets its food and oxygen from the mother's blood through a special organ called the placenta. The placenta acts like a bridge, bringing good things to the baby and taking waste away.

🎯 Exam Tip: Emphasize the placenta's dual role in facilitating nutrient/oxygen transfer to the fetus and waste removal, highlighting its critical function during pregnancy.

 

Question 10. Identify the parts A, B, C and D.

Answer:
A - Exine
B - Intine
C - Generative nucleus
D - Vegetative nucleus
In simple words: This diagram shows the different parts of a pollen grain, which are important for plant reproduction. Each part has a specific job in carrying the male genetic material.

🎯 Exam Tip: Be able to label the internal and external structures of a pollen grain, including the protective layers and the two nuclei.

 

Question 11. Write the events involved in the sexual reproduction of a flowering plant.
1. Discuss the first event and write the types.
2. Mention the advantages and disadvantages of that event.
Answer:
1. The first event in the sexual reproduction of a flowering plant is Pollination. Pollination is the transfer of pollen grains from the anther (male part) to the stigma (female part) of a flower. The two main types of pollination are:

• Self-pollination: When pollen is transferred from the anther to the stigma of the same flower or another flower on the same plant.
• Cross-pollination: When pollen is transferred from the anther of one flower to the stigma of a flower on a different plant of the same species.

2. Advantages of Pollination:

• It leads to fertilization, which is essential for the formation of fruits and seeds, ensuring the continuation of the plant species.
• Cross-pollination helps in creating new varieties of plants by combining different genes, which can lead to stronger plants.
• More viable seeds are produced through cross-pollination due to genetic diversity.

Disadvantages of Pollination:

• There can be significant wastage of pollen grains, especially in wind-pollinated flowers, as not all pollen reaches a stigma.
• Pollination might fail if there are distance barriers or a lack of suitable pollinators.
• Sometimes, undesirable traits can be introduced into the plants through cross-pollination.
• Many flowers rely on external agents like insects or wind for pollination, making them dependent on these external factors.

In simple words: The first step is pollination, which means moving pollen from one part of a flower to another, or to a different flower. This can be self-pollination (on the same plant) or cross-pollination (between different plants). Pollination is good because it makes fruits and seeds and new types of plants, but it can waste pollen and sometimes needs help from wind or insects.

🎯 Exam Tip: Structure your answer clearly, separating the definition, types, advantages, and disadvantages to ensure all parts of the question are addressed comprehensively.

 

Question 12. Why are the human testes located outside the abdominal cavity? Name the pouch in which they are present.
Answer: Human testes are located outside the abdominal cavity because sperm production (spermatogenesis) requires a slightly lower temperature than the normal body temperature. The abdominal cavity is too warm for healthy sperm development. The testes are present in a sac-like structure called the scrotum, which helps to maintain this optimal lower temperature.
In simple words: The testes are outside the body because they need to be a bit cooler than the inside of the body to make sperm correctly. They are held in a skin pouch called the scrotum.

🎯 Exam Tip: Clearly state the temperature requirement for spermatogenesis and name the scrotum as the anatomical solution to this requirement.

 

Question 13. The luteal phase of the menstrual cycle is also called the secretory phase. Give reason.
Answer: The luteal phase of the menstrual cycle is also called the secretory phase because, during this time, the hormone progesterone is largely produced by the corpus luteum (which develops from the Graafian follicle after ovulation). Progesterone stimulates the uterine lining (endometrium) to become thicker and highly glandular, secreting fluids rich in nutrients. This makes the uterus ready to receive and support a fertilized egg, if implantation occurs.
In simple words: The luteal phase is called the secretory phase because the uterus starts making and releasing many substances, mainly due to the hormone progesterone. This prepares the womb for a possible baby.

🎯 Exam Tip: Link the term "secretory" directly to the endometrial secretions stimulated by progesterone during the luteal phase, highlighting its role in preparing the uterus for implantation.

 

Question 14. Why are family planning methods not adopted by all the people of our country?
Answer: Family planning methods are not universally adopted in some countries for several reasons. Primarily, it is a voluntary decision, and many people may not be fully aware of its importance for personal and family health, or for societal well-being. Factors such as lack of education, cultural beliefs, religious views, limited access to healthcare, economic constraints, and social stigma can also prevent widespread adoption. These issues mean that not everyone understands or has the means to use family planning effectively.
In simple words: Not everyone uses family planning because some people don't know about it, or they have different beliefs, or it's hard to get the services. It's a choice, and many things can stop people from making that choice.

🎯 Exam Tip: When discussing adoption of health practices, consider a range of influencing factors including education, socio-cultural beliefs, and accessibility of services.

 

VII. Long Answer Questions.

 

Question 1. With a neat labelled diagram describe the parts of a typical angiospermic ovule.
Answer: The ovule is a small structure found within the ovary of a flowering plant, essential for seed formation. Its main part is the nucellus, a mass of nutritive tissue. The nucellus is protected by one or two outer layers called integuments, which leave a small opening at one end called the micropyle. The ovule is attached to the ovary wall by a stalk called the funiculus. Opposite to the micropylar end is the chalaza, which represents the basal part of the ovule. Inside the nucellus is the embryo sac, which contains seven cells and eight nuclei. These include three cells at the micropylar end forming the egg apparatus (one egg cell and two synergids), three antipodal cells at the chalazal end, and two polar nuclei in the center that fuse to form a central cell. This intricate structure ensures proper development after fertilization.
In simple words: An ovule is like a small egg in a flower that becomes a seed. It has a main nourishing part (nucellus), outer covers (integuments), a tiny opening (micropyle), and is connected by a stalk (funiculus). Inside, there's a sac (embryo sac) with cells, including the egg, ready for fertilization.

🎯 Exam Tip: For diagrams, ensure all parts mentioned in the description are clearly labeled. Pay attention to the relative positions and functions of each part of the ovule.

 

Question 2. What are the phases of menstrual cycle? Indicate the changes in the ovary and changes in the uterus.

Answer: The menstrual cycle is a series of natural changes in hormone production and the structure of the uterus and ovaries of the female reproductive system. It prepares the uterus for the possibility of pregnancy. The table above summarizes the main phases, their typical duration, and the corresponding changes that occur in both the ovary and the uterus, showcasing the synchronized nature of these events.
In simple words: The menstrual cycle has different stages, each with specific changes in the ovary (where eggs grow) and the uterus (the womb). These changes prepare a woman's body for a possible pregnancy each month.

🎯 Exam Tip: When describing the menstrual cycle, always explain the synchronized events in both the ovary and the uterus, along with the hormonal influences, to show a complete understanding.

VIII. Higher Order Thinking Skills (HOTS)

 

Question 1. In angiosperms, the pollen germinates to produce a pollen tube that carries two gametes. What is the purpose of carrying two gametes when single gamete can fertilize the egg?
Answer: In flowering plants (angiosperms), pollen tubes carry two male gametes. One gamete joins with the egg cell, a process called syngamy, forming a diploid zygote that grows into a new plant. The second gamete merges with the secondary nucleus, known as triple fusion, to create the primary endosperm. This endosperm is crucial because it develops into a tissue that provides food and nourishment for the growing embryo. The presence of two gametes ensures both embryo development and its nutritional support.
In simple words: Flowering plants send two cells (gametes) with the pollen tube. One cell makes the new plant, and the other cell makes food for that new plant to grow.

🎯 Exam Tip: Remember that double fertilization, unique to angiosperms, is a two-part process that ensures both embryo formation and nutrient supply through endosperm development.

 

Question 2. Why menstrual cycle does not take place before puberty and during pregnancy?
Answer: Menstruation happens when an egg is not fertilized. The uterus lining thickens each month to prepare for a fertilized egg; if no fertilization occurs, this lining breaks down and is shed as blood. Before puberty, a girl's body is not yet ready to release eggs or prepare the uterus lining for pregnancy, so the menstrual cycle does not start. During pregnancy, a fertilized egg is already implanted, and the body produces hormones that stop menstruation to protect the growing baby and maintain the uterine lining.
In simple words: Periods don't happen before a girl's body is old enough to have babies, or when she is already pregnant because a baby is growing inside.

🎯 Exam Tip: Key hormones like estrogen and progesterone play a crucial role in regulating the menstrual cycle and maintaining pregnancy.

 

Question 3. Read the following passage and answer the questions that follow: Rohini and her parents were watching a television programme. An advertisement flashed on the screen which was promoting the use of sanitary napkins. Rohini's parents suddenly changed the channel, but she objected to her parents and explained the need and importance of such advertisement.
(a) What is first menstruation called? When does it occur?
(b) List out the napkin hygiene measures taken during menstruation?
(c) Do you think Rohini's objection towards her parents was correct? If so, Why?
Answer:
(a) The first menstrual period a girl experiences is called Menarche. This typically happens when she is between 12 and 15 years old, marking the beginning of her reproductive years.
In simple words: A girl's very first period is called Menarche, and it usually starts when she is about 12 to 15 years old.
(b) To maintain hygiene during menstruation, sanitary pads and tampons should be wrapped well before throwing them away to stop the spread of germs. It is also important not to flush them down the toilet as they can cause blockages in plumbing systems. Proper disposal helps keep public sanitation good.
In simple words: Pads and tampons should be wrapped and put in the bin, never flushed, to keep things clean and prevent germs from spreading.
(c) Yes, Rohini's objection to her parents changing the channel was correct. It is important for parents and teachers to educate girls about using and properly disposing of sanitary napkins. Such advertisements on television help spread this crucial information, so it's beneficial for girls to see them and learn about menstrual hygiene. Learning about menstrual hygiene is a vital part of health education.
In simple words: Yes, Rohini was right. It's important for everyone to learn about sanitary pads and how to dispose of them properly, and TV ads can help teach this.

🎯 Exam Tip: When answering passage-based questions, always refer back to the text for context and specific details, while expressing the answer in your own simple words.

Samacheer Kalvi 10th Science Reproduction in Plants and Animals Additional Important Questions and Answers

I. Choose the correct answer:

 

Question 1. In a pollen grain the small nucleus is:
(a) Generative nucleus
(b) Tube nucleus
(c) Vegetative nucleus
(d) Pollen nucleus
Answer: (a) Generative nucleus
In simple words: Inside a pollen grain, the smaller nucleus that helps in reproduction is called the generative nucleus. This nucleus will later divide to form two male gametes.

🎯 Exam Tip: Differentiate between the generative nucleus (for gametes) and the vegetative nucleus (for pollen tube growth) in a pollen grain.

 

Question 2. The female part of the flower is _______
(a) Androecium
(b) Anemophily
(c) Gynoecium
(d) Micropyle.
Answer: (c) Gynoecium
In simple words: The Gynoecium is the female part of a flower, containing the ovary, style, and stigma. It is where seeds develop after fertilization.

🎯 Exam Tip: Remember that the pistil or carpel is the individual unit, while the gynoecium refers to the entire female reproductive whorl of a flower.

 

Question 3. Spirogyra is an:
(a) Virus
(b) Fungi
(c) Bacteria
(d) Algae
Answer: (d) Algae
In simple words: Spirogyra is a type of green algae found in fresh water, known for its spiral chloroplasts. Algae are simple plant-like organisms that make their own food.

🎯 Exam Tip: Recall that algae are photosynthetic organisms often found in aquatic environments, differing from fungi, bacteria, and viruses in their cell structure and mode of nutrition.

 

Question 4. During pregnancy, the uterus expands, it's normal size up to _______.
(a) 200 times
(b) 500 times
(c) 600 times
(d) 800 times.
Answer: (b) 500 times
In simple words: The uterus, which is a muscular organ, grows a lot during pregnancy to hold the baby. It can expand up to 500 times its original size.

🎯 Exam Tip: Understand that the uterus is a highly adaptable organ, and its remarkable expansion capacity is a key feature for fetal development.

 

Question 5. In wind pollinated flowers, the pollen grains are:
(a) sticky and powdery
(b) small and powdery
(c) dry and powdery
(d) wet and powdery
Answer: (c) dry and powdery
In simple words: Flowers pollinated by wind have very light, dry, and powdery pollen. This helps the pollen easily fly through the air to reach other flowers.

🎯 Exam Tip: Characteristics like light, dry pollen and large, feathery stigmas are adaptations that facilitate efficient wind pollination (anemophily).

 

Question 6. Androecium is the _______ part of the flower.
(b) male
(c) lower
(d) female
Answer: (b) male
In simple words: The Androecium is the male part of a flower, made up of stamens that produce pollen. This part is essential for the flower to reproduce.

🎯 Exam Tip: Connect the term Androecium to its function in male reproduction, similar to how Gynoecium relates to female reproduction.

 

Question 7. Zygote is a resulting product of:
(a) Germination
(b) Pollination
(c) Fusion of Embryosac
(d) Fertilization
Answer: (d) Fertilization
In simple words: A zygote is formed when a male reproductive cell (sperm) joins with a female reproductive cell (egg). This joining is called fertilization.

🎯 Exam Tip: The zygote is the single-celled product of fertilization, which then undergoes cell division to develop into an embryo.

 

Question 8. Pick out the correct statement:
(a) Endosperm is a connective tissue
(b) Endosperm is a muscular tissue
(c) Endosperm is a nutritive tissue
(d) Endosperm is a nervous tissue
Answer: (c) Endosperm is a nutritive tissue
In simple words: The endosperm is a special part of a seed that acts as food storage for the developing plant embryo. It provides all the necessary nutrients for growth.

🎯 Exam Tip: The primary role of endosperm is nutrition, which is crucial for the early stages of embryo development in plants.

 

Question 9. The follicle that ruptures at the time of ovulation promptly fills with blood, forming:
(a) Corpus Luteum
(c) Corpus Collosum
(d) Corpus Haemorrhagueim
Answer: (a) Corpus Luteum
In simple words: After an egg is released during ovulation, the leftover part of the follicle changes and fills with blood, then transforms into a structure called the Corpus Luteum. This structure produces hormones important for possible pregnancy.

🎯 Exam Tip: The corpus luteum is vital for producing progesterone, which maintains the uterine lining for potential embryo implantation.

 

Question 10. The endometrium is the lining of:
(a) bladder
(b) vagina
(c) uterus
(d) oviduct
Answer: (c) uterus
In simple words: The endometrium is the inner layer of the uterus. This lining thickens each month to prepare for a fertilized egg to implant.

🎯 Exam Tip: Remember that the endometrium is the site of embryo implantation and is shed during menstruation if pregnancy does not occur.

 

Question 11. Menstrual flow occurs due to lack of:
(a) Progesterone
(b) FSH
(c) Oxytocin
(d) Vasopressin
Answer: (a) Progesterone
In simple words: Menstrual bleeding happens when the body's progesterone hormone level drops. This drop causes the uterus lining, which had prepared for pregnancy, to break down and shed.

🎯 Exam Tip: Progesterone is the key hormone that maintains the uterine lining; a decline in its level directly triggers menstruation.

 

Question 12. Testosterone is secreted by:
(a) Leydig cells
(b) Sertoli cells
(c) Seminiferous tubule
(d) None of these
Answer: (a) Leydig cells
In simple words: Testosterone, the main male hormone, is produced by special cells called Leydig cells. These cells are found in the testes and are important for male development and reproduction.

🎯 Exam Tip: Distinguish between Leydig cells (produce testosterone) and Sertoli cells (support sperm development) within the testes.

 

Question 13. In mammals, maturation of sperms take place at a temperature:
(a) Equal to that of body
(b) Higher than that of body
(c) Lower than that of body
(d) At any piece of mammalian sperm
Answer: (c) Lower than that of body
In simple words: For sperm to fully develop and become mature in mammals, they need a temperature that is slightly cooler than the normal body temperature. This is why testes are located outside the body.

🎯 Exam Tip: This physiological requirement for lower temperature explains the evolutionary placement of testes in the scrotum, external to the abdominal cavity.

 

Question 14. If menstrual cycle is 30 days and bleeding starts on 1st day, then ovulation occur on:
(a) 14th day
(b) 18th day
(c) 30th day
(d) 16th day
Answer: (d) 16th day
In simple words: If a menstrual cycle is 30 days long and bleeding begins on day 1, ovulation, which is when an egg is released, usually happens around the middle of the cycle. In this case, it would be around day 16.

🎯 Exam Tip: Ovulation typically occurs about 14 days before the next menstrual period starts, regardless of the overall cycle length.

 

Question 15. The symbol of family planning in India is:
(a) Square
(b) Inverted red triangle
(c) Rectangle
(d) Circle
Answer: (b) Inverted red triangle
In simple words: In India, the symbol used to represent family planning programs and services is an inverted red triangle. This symbol helps people easily recognize information about family welfare.

🎯 Exam Tip: Recognize common public health symbols as they often convey important information clearly and concisely.

II. Fill in the blanks:

 

Question 1. Purpose of tubectomy is to prevent _________.
Answer: Fertilization
In simple words: Tubectomy is a surgical procedure done in females specifically to stop the egg and sperm from meeting, thereby preventing fertilization.

🎯 Exam Tip: Understand that tubectomy is a permanent method of contraception that physically blocks the path of the egg.

 

Question 2. Progesterone is secreted by _________.
Answer: Corpus luteum
In simple words: The hormone progesterone, important for maintaining pregnancy, is produced by the corpus luteum, a temporary gland that forms in the ovary after ovulation.

🎯 Exam Tip: The corpus luteum is crucial for producing progesterone, which prepares the uterus for pregnancy and prevents further ovulation.

 

Question 3. Sertoli cells are found in _________.
Answer: Seminiferous tubule
In simple words: Sertoli cells, which support and nourish developing sperm, are located within the seminiferous tubules in the testes.

🎯 Exam Tip: Remember that Sertoli cells are essential for spermatogenesis, providing both structural support and nutritional factors to the developing sperm.

 

Question 4. Hormone responsible for ovulation and development of corpus luteum is _________.
Answer: LH
In simple words: Luteinizing Hormone (LH) is the hormone that triggers ovulation and also helps in the formation and development of the corpus luteum after the egg is released.

🎯 Exam Tip: The surge in LH is often referred to as the "LH surge" and is a key indicator of impending ovulation.

 

Question 5. First menstrual cycle starts is _________.
Answer: Menarche
In simple words: The very first menstrual cycle a female experiences in her life is known as menarche, marking the start of her reproductive years.

🎯 Exam Tip: Menarche is a significant developmental milestone, indicating the onset of reproductive maturity in females.

 

Question 6. The functional maturation of sperms takes place in _________.
Answer: Epididymis
In simple words: After sperm are produced, they travel to the epididymis, a coiled tube, where they finish developing and become fully mature and able to fertilize an egg.

🎯 Exam Tip: The epididymis is vital not just for sperm maturation but also for their storage before ejaculation.

 

Question 7. Seeds develops from _________.
Answer: Ovule
In simple words: In plants, after fertilization, the ovule inside the flower develops and grows into a seed, which can then grow into a new plant.

🎯 Exam Tip: Recall that the ovary develops into the fruit, while the ovules within it develop into the seeds after fertilization.

 

Question 8. In _________ buds are produced in the notches along the leaf margin.
Answer: Bryophyllum
In simple words: The Bryophyllum plant is unique because it grows tiny new plants, called buds, right from the edges of its leaves, which can then fall off and grow into independent plants.

🎯 Exam Tip: Bryophyllum is a classic example of vegetative propagation through leaves, making it easy to grow new plants from a single leaf.

 

Question 9. Androecium is a group of _________.
Answer: Stamens
In simple words: The androecium refers to all the male parts of a flower together, which are made up of individual units called stamens, responsible for producing pollen.

🎯 Exam Tip: Understand the hierarchy: a flower has whorls, one of which is the androecium, composed of multiple stamens.

 

Question 10. In self-pollination, flowers need not to depend on _________ of pollination.
Answer: Agents
In simple words: When a flower self-pollinates, it means its own pollen fertilizes its own ovules, so it doesn't need external helpers like insects or wind, which are called agents of pollination.

🎯 Exam Tip: Self-pollination can occur in bisexual flowers, or even unisexual flowers if they are on the same plant (geitonogamy).

 

Question 11. Pollination by wind is called _________.
Answer: Anemophily
In simple words: The process where wind carries pollen from one flower to another for fertilization is specifically known as anemophily, a common type of pollination.

🎯 Exam Tip: Wind-pollinated flowers often lack bright colors, scent, or nectar, as they don't need to attract animal pollinators.

 

Question 12. The point of attachment of ovule to the funicle is known as _________.
Answer: Micropyle
In simple words: The micropyle is a small opening at one end of the ovule where the funicle, which is the stalk attaching the ovule to the ovary wall, connects. It also allows the entry of the pollen tube.

🎯 Exam Tip: While the hilum is the true point of attachment of the funicle to the ovule, the micropyle is an important opening for pollen tube entry.

 

Question 13. In Angiosperm pollen tube liberate their _________ into the _________.
Answer: Male gametes
In simple words: In flowering plants (angiosperms), the pollen tube grows down to the ovule and releases its male gametes inside, leading to fertilization.

🎯 Exam Tip: The pollen tube provides a direct pathway for the male gametes to reach the ovule, overcoming potential barriers.

 

Question 14. Double fertiliztaion is essential for formation of _________.
Answer: Endosperm
In simple words: Double fertilization, a unique process in flowering plants, is important because it leads to the formation of the endosperm, which provides food for the developing plant embryo.

🎯 Exam Tip: Double fertilization ensures that the nutritional tissue (endosperm) only develops if fertilization of the egg cell has successfully occurred.

 

Question 15. During spore formation a structure called _________ develops from the fungal hypha.
Answer: Sporangium
In simple words: When fungi reproduce by spores, a specialized structure called a sporangium forms from the hyphae, which then produces and releases the spores.

🎯 Exam Tip: Sporangia are common in many fungi and certain plants, serving as a protective casing for spores during their development.

III. Match the following

 

Question 1. Match the Column I with Column II.

Answer:
A. (ii) Amoeba
B. (iii) Yeast
C. (i) Spirogyra
In simple words: Fission is how Amoeba divides, budding is how Yeast grows new cells, and fragmentation is how Spirogyra breaks into new pieces. Each is a different way living things reproduce.

🎯 Exam Tip: Understand these as examples of asexual reproduction, where a single parent produces offspring without the fusion of gametes.

 

Question 2. Match the Column I with Column II

Answer:
A. (iii) Delivery of baby from uterus
B. (i) Duration between pregnancy and birth
C. (iv) Release of egg from Graffian follicle
D. (ii) Attachment of zygote to endometrium
In simple words: Parturition is giving birth, gestation is the total time of pregnancy, ovulation is when an egg is released, and implantation is when the fertilized egg attaches to the uterus. These are key steps in reproduction.

🎯 Exam Tip: Clearly define each term and remember the sequence of events in human reproduction, from ovulation to birth.

IV. Assertion and Reasoning:

 

Question 1. Assertion (A): Some of the Angiospermic plants are propagated only by vegetative propagation. Reason (R): They have lost the capacity of seed formation.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (a) If both A and R are true and R is correct explanation of A.
In simple words: For some flowering plants, both the statement that they reproduce only vegetatively and the reason that they cannot form seeds are correct. The reason accurately explains why they rely on vegetative reproduction.

🎯 Exam Tip: When evaluating Assertion-Reason questions, first check if both statements are true individually, then assess if the reason correctly explains the assertion.

 

Question 2. Assertion (A): Double fertilization is the universal features of all plants. Reason (R): In this fusion only male gametes and secondary nucleus takes place.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (d) Both A and R are false.
In simple words: The assertion that double fertilization happens in all plants is false because it only occurs in flowering plants (angiosperms). The reason is also false because double fertilization involves two fusions, not just one, and also includes the egg cell.

🎯 Exam Tip: Remember that double fertilization is a defining characteristic of angiosperms, not all plants, and it involves fusion with both the egg and the central cell.

 

Question 3. Assertion (A): The unit of Androecium is called stamen. Reason (R): The most important part of androecium is anther.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (c) A is true but R is false.
In simple words: The statement that a stamen is the basic unit of the androecium (male part of a flower) is true. However, the reason that the anther is the *most important* part of the androecium is false; while the anther is vital for pollen production, the entire stamen, including the filament, is the unit.

🎯 Exam Tip: While the anther contains pollen, the stamen (anther + filament) is the complete reproductive unit, and the androecium is the collective term for all stamens.

 

Question 4. Assertion (A): Anemophily includes wastage of pollen grains. Reason (R): Anemophilous flowers are neither attractive nor fragrant.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (b) If both A and R are true but R is not the correct explanation of A.
In simple words: Both the assertion that wind pollination (anemophily) causes a lot of pollen to be wasted and the reason that wind-pollinated flowers are not showy or smelly are true. However, the lack of attractiveness doesn't directly *explain* the wastage; wastage happens because pollen is scattered broadly by wind.

🎯 Exam Tip: Wastage in wind pollination is due to the indiscriminate nature of wind as a carrier, while the lack of attractiveness is an adaptation to save energy since no animal pollinator needs to be attracted.

 

Question 5. Assertion (A): Sexual reproduction takes place with the participation of two different type of gametes. Reason (R): Sexual reproduction is also known as Apomixies.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (c) A is true but R is false.
In simple words: The assertion that sexual reproduction involves two different types of reproductive cells (gametes) is true. However, the reason that sexual reproduction is also called Apomixies is false, as apomixis is a type of asexual reproduction.

🎯 Exam Tip: Apomixis is a form of asexual reproduction that mimics sexual reproduction by producing seeds without fertilization, but it does not involve the fusion of gametes.

 

Question 6. Assertion (A): In India, IUDS most widely accepted methods of contraception. Reason (R): IUDS are injectable contraceptives, which prevent pregnancy for three months.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (c) A is true but R is false.
In simple words: The statement that Intrauterine Devices (IUDs) are widely used for contraception in India is true. But the reason given, that IUDs are injectable contraceptives that last three months, is false; IUDs are placed in the uterus and last for several years, while injectables are a different method.

🎯 Exam Tip: Differentiate between different contraceptive methods; IUDs are long-acting reversible contraceptives, distinct from shorter-term injectable methods.

 

Question 7. Assertion (A): Over population has become a serious problem in developing countries. Reason (R): It may exhaust natural resources, cause unemployment and lead to pollution.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (a) If both A and R are true and R is correct explanation of A.
In simple words: Both the assertion that overpopulation is a major issue in developing nations and the reason that it depletes resources, causes joblessness, and increases pollution are true. The reason accurately explains the negative impacts of overpopulation.

🎯 Exam Tip: Recognize the interconnectedness of population growth with environmental degradation, economic strain, and social issues, particularly in developing economies.

V. State whether True or false, If false write the correct statement

 

Question 1. Tubectomy a method of population control performed on males.
Answer: False - Tubectomy is a method of population control performed on females.
In simple words: This statement is false because tubectomy is a surgical procedure for women to prevent pregnancy. For men, the equivalent procedure is called vasectomy.

🎯 Exam Tip: Clearly distinguish between tubectomy (female sterilization) and vasectomy (male sterilization), as they are different procedures for different sexes.

 

Question 2. Oral pills are very popular contraceptives among the rural women.
Answer: False - Oral pills are very popular contraceptives among the urban women.
In simple words: This statement is false. While oral pills are a common birth control method, they are often more popular among women in cities rather than rural areas due to factors like access and awareness.

🎯 Exam Tip: Factors such as access to healthcare, education, and cultural acceptance influence the popularity and adoption of specific contraceptive methods in different demographics.

 

Question 4. Vegetative reproduction is a kind of asexual reproduction.
Answer: True
In simple words: This statement is true. Vegetative reproduction is a way plants make new plants from parts like stems, roots, or leaves, without needing seeds or spores, so it's a form of asexual reproduction.

🎯 Exam Tip: Vegetative reproduction produces genetically identical offspring (clones) to the parent plant, a hallmark of asexual reproduction.

 

Question 5. The protective wall of the pollen is intine.
Answer: False - The protective wall of the pollen is exine.
In simple words: This statement is false. The strong outer protective layer of a pollen grain is called the exine. The intine is the thinner, inner layer.

🎯 Exam Tip: Remember the two layers of the pollen grain wall: the tough outer exine for protection and the inner intine for pollen tube formation.

VI. Answer in a word or sentence:

 

Question 1. Define reproduction.
Answer: Reproduction is the biological process by which living organisms create new individuals, or offspring, that are similar to themselves. This ensures the continuation of the species.
In simple words: Reproduction means living things make new living things that look like them.

🎯 Exam Tip: Emphasize that reproduction is fundamental to the survival of a species, ensuring the transfer of genetic material to the next generation.

 

Question 2. Define Fertilization.
Answer: Fertilization is the process where a male reproductive cell (gamete) joins with a female reproductive cell (gamete) to form a new single cell called a zygote. This is the first step in creating a new organism.
In simple words: Fertilization is when a male cell and a female cell combine to make a new cell called a zygote, which then grows into a baby.

🎯 Exam Tip: The formation of a zygote is the critical outcome of fertilization, initiating the development of a new individual.

 

Question 3. Where the fertilization takes place in human female?
Answer: In human females, fertilization usually happens in the oviduct, specifically in a wider part called the ampulla of the fallopian tube. This is where the sperm and egg typically meet.
In simple words: In women, the egg and sperm usually meet and join in a tube called the fallopian tube.

🎯 Exam Tip: The fallopian tube provides the optimal environment for fertilization to occur due to its ciliary action and chemical signals that guide sperm and egg.

 

Question 5. Define Menstruation.
Answer: Menstruation is a regular biological process in females that occurs from puberty until menopause. It involves the shedding of the uterine lining, which happens when an egg released by the ovary is not fertilized by sperm.
In simple words: Menstruation, or a period, is a regular bleeding that happens to women when their body releases an egg that doesn't get fertilized by sperm.

🎯 Exam Tip: Understand menstruation as part of a cyclical preparation for pregnancy; its occurrence indicates that fertilization did not take place in that cycle.

 

Question 6. Write the name of male and female reproductive part of a flower.
Answer: The male reproductive part of a flower is called the Androecium, and the female reproductive part is called the Gynoecium. These parts are crucial for plant reproduction.
In simple words: The male part of a flower is the Androecium, and the female part is the Gynoecium.

🎯 Exam Tip: Remember these Greek-derived terms: 'andro' for male and 'gyno' for female, which apply to many biological contexts.

 

Question 7. Define gestation period.
Answer: Gestation period is the time from when a fertilized egg implants in the uterus until the baby is born. During this period, the embryo or fetus grows and develops inside the mother's womb.
In simple words: Gestation is the whole time a baby grows inside its mother, from when it starts until it's born.

🎯 Exam Tip: The gestation period varies significantly among different species, reflecting their developmental rates and ecological needs.

 

Question 8. What is the gestation period in human?
Answer: In humans, the normal gestation period, which is how long a pregnancy lasts, is about 280 days. This is roughly equivalent to 40 weeks or nine months.
In simple words: For humans, pregnancy usually lasts about 280 days, or around nine months.

🎯 Exam Tip: The 280-day period is typically calculated from the first day of the last menstrual period, not from the date of conception.

 

Question 9. Write the full form of IUD and AIDS.
Answer: IUD stands for Intrauterine Devices, which are small devices placed in the uterus for birth control. AIDS stands for Acquired Immunodeficiency Syndrome, a serious condition caused by the HIV virus that weakens the body's immune system.
In simple words: IUD means Intrauterine Devices, used for birth control. AIDS means Acquired Immunodeficiency Syndrome, a disease that harms the body's defense system.

🎯 Exam Tip: Knowing acronyms like IUD and AIDS, and their full forms, is important for understanding reproductive health and global health issues.

 

Question 10. What is Menopause?
Answer: Menopause is a natural drop in a woman's reproductive hormones. It happens when a woman reaches around 48-50 years of age, marking the end of her menstrual cycles. It is a significant biological change.
In simple words: Menopause is when a woman's body naturally stops making certain hormones, and her periods stop around age 48-50.

🎯 Exam Tip: Remember that menopause is a natural biological process, not a disease or disorder, and involves a gradual decline in hormone production.

 

Question 11. Define Pollination.
Answer: Pollination is the process where pollen grains move from the anther (male part) to the stigma (female part) of a flower. This transfer is crucial for plants to make seeds and fruits. It is the first step towards plant reproduction.
In simple words: Pollination is when pollen moves from one part of a flower to another, or to a different flower, so that seeds can be made.

🎯 Exam Tip: When defining pollination, make sure to mention both the "from" (anther) and "to" (stigma) parts of the flower for completeness.

 

Question 12. What are the agents of pollination?
Answer: The agents of pollination are the things that help transfer pollen from one flower to another. These can be living things or non-living things. Common agents include animals like insects (bees, butterflies), birds, and bats; and non-living elements like wind and water.
In simple words: Animals (like insects) and natural forces (like wind and water) are the main things that help move pollen around for pollination.

🎯 Exam Tip: List both biotic (animals, insects) and abiotic (wind, water) agents of pollination to show a complete understanding.

 

Question 13. What is Parturition?
Answer: Parturition is the process of giving birth, where a fully developed baby is expelled from the mother's uterus. It marks the end of the gestation period (pregnancy). This complex process involves hormones and uterine contractions.
In simple words: Parturition is simply the act of a mother giving birth to her baby after pregnancy.

🎯 Exam Tip: Define parturition as the expulsion of a young one from the uterus at the end of gestation, linking it to the completion of pregnancy.

 

Question 14. What is endometrium?
Answer: The endometrium is the inner lining of the uterus in mammals. It is a mucous membrane that thickens each month to prepare for a possible pregnancy. If pregnancy does not occur, this lining is shed during menstruation.
In simple words: The endometrium is the soft inner layer of the uterus where a baby grows, and it's shed during a period if there's no pregnancy.

🎯 Exam Tip: Emphasize that the endometrium is the "inner lining" of the uterus and its role in both implantation and menstruation.

 

Question 15. What are gonads?
Answer: Gonads are the primary reproductive organs in animals, responsible for producing gametes (sex cells) and sex hormones. In males, the gonads are the testes, which produce sperm. In females, the gonads are the ovaries, which produce eggs. They are vital for reproduction and hormone balance.
In simple words: Gonads are the body parts that make sex cells (like sperm or eggs) and sex hormones. Testes are male gonads, and ovaries are female gonads.

🎯 Exam Tip: Clearly state that gonads are reproductive organs, give examples for both males (testes) and females (ovaries), and mention their dual role of producing gametes and hormones.

 

Question 16. Name two sexually transmitted disease.
Answer: Two sexually transmitted diseases (STDs) are Syphilis and AIDS. These diseases can be passed from one person to another through sexual contact. Practicing safe sex can help prevent their spread.
In simple words: Syphilis and AIDS are two diseases that can spread through sexual activity.

🎯 Exam Tip: When asked to list diseases, choose common and well-known examples like Syphilis and AIDS.

 

Question 17. What is Vitelline membrane?
Answer: The vitelline membrane is a protective layer that surrounds the plasma membrane of an ovum (egg cell). It plays an important role in fertilization by helping to prevent more than one sperm from entering the egg. This membrane is the outermost layer of the egg before fertilization.
In simple words: The vitelline membrane is a thin layer around an egg cell that helps protect it and controls which sperm can get in.

🎯 Exam Tip: Describe the vitelline membrane as the surface layer of the ovum, highlighting its role in protecting the egg and regulating sperm entry.

 

Question 18. Which parts of the flower transform into the seed and fruit?
Answer: In a flower, the ovule develops into the seed after fertilization. The ovary, which encloses the ovules, then ripens and grows into the fruit. This transformation is essential for the plant's reproduction and seed dispersal.
In simple words: After a flower is fertilized, its ovule becomes the seed, and the ovary around it becomes the fruit.

🎯 Exam Tip: Clearly link "ovule to seed" and "ovary to fruit" as these are the direct transformations after fertilization.

 

Question 19. Name two sex hormones.
Answer: Two important sex hormones are Testosterone and Progesterone. Testosterone is primarily a male sex hormone, while Progesterone is primarily a female sex hormone. These hormones regulate reproductive processes and development of secondary sexual characteristics.
In simple words: Testosterone and Progesterone are two important hormones that control sex development and reproduction.

🎯 Exam Tip: When asked for two sex hormones, naming one male hormone (Testosterone) and one female hormone (Progesterone) is a good approach.

 

Question 20. What is umblical cord?
Answer: The umbilical cord is a tube-like structure containing blood vessels that connects a developing fetus to the placenta inside the mother's womb. It carries oxygen and nutrients from the mother to the baby and waste products from the baby back to the mother. This cord is essential for fetal growth and survival.
In simple words: The umbilical cord is a rope-like tube that connects a growing baby to its mother, carrying food and oxygen.

🎯 Exam Tip: Define the umbilical cord by its function (connecting fetus to placenta) and its main role (transporting nutrients, oxygen, and waste).

VII. Short Answer Questions

 

Question 1. What is vegetative reproduction? Give an example.
Answer: Vegetative reproduction is a type of asexual reproduction in plants where new plantlets grow from the vegetative (non-sexual) parts of a parent plant, like its roots, stems, or leaves. For example, in Bryophyllum, small plants sprout from the notches along the edges of its leaves. This method allows plants to reproduce without seeds or spores.
In simple words: Vegetative reproduction is when a new plant grows from a part of an old plant, like a leaf or stem, instead of from a seed. Bryophyllum leaves can do this.

🎯 Exam Tip: Define vegetative reproduction as asexual reproduction from plant parts, and always include a clear example like Bryophyllum or sweet potato.

 

Question 2. What happens when the egg is not fertilized?
Answer: If an egg is not fertilized, the corpus luteum (a structure in the ovary) breaks down. This causes the egg to disintegrate, and the uterine lining, which had thickened in preparation for pregnancy, slowly breaks away. This shedding of blood and mucus from the uterus is known as menstruation. This process prepares the uterus for a new cycle.
In simple words: If an egg is not fertilized, it breaks down, and the uterus sheds its lining, causing a menstrual period.

🎯 Exam Tip: Focus on the key events: corpus luteum degeneration, egg disintegration, and the shedding of the uterine lining resulting in menstruation.

 

Question 3. Explain the types of Urinary Tract Infection?
Answer: Women are more prone to Urinary Tract Infections (UTIs) caused by bacteria found on the skin, in the rectum, or vagina. There are different types of UTIs:

• Cystitis (Bladder infection): This happens when bacteria settle in the urinary bladder, often seen in people aged 20 to 50, causing inflammation.
• Kidney Infection: If bacteria travel upwards from the bladder to the ureters and reach the kidneys, it can cause a serious kidney infection. This can even spread to the bloodstream.
• Asymptomatic Bacteriuria: In this type, bacteria are present in the urinary bladder, but the person shows no noticeable symptoms. This can still be a concern if not monitored.

Urinary tract infections can range from mild to severe, making early diagnosis and treatment important.
In simple words: UTIs are infections in the urinary system, usually caused by bacteria. They can be bladder infections (Cystitis), kidney infections if they spread, or even exist without symptoms (Asymptomatic Bacteriuria).

🎯 Exam Tip: List the specific types of UTIs (Cystitis, Kidney Infection, Asymptomatic Bacteriuria) and briefly describe what each involves.

 

Question 4. How does reproduction help in providing stability to population of species?
Answer: Reproduction ensures the ongoing existence and survival of a species by producing new individuals. This process helps maintain a stable population size over generations, as new offspring replace older, dying members. It's a fundamental way species continue to thrive and prevent extinction, ensuring the species' self-perpetuation. Without reproduction, populations would decline and eventually disappear.
In simple words: Reproduction keeps a species alive and stable by making new babies to replace older members, so the group doesn't die out.

🎯 Exam Tip: Connect reproduction directly to "continuity and survival of species" and "maintaining population stability" by replacing older individuals.

 

Question 5. What is vegetative propagation? Write two examples where it is used.
Answer: Vegetative propagation is a method of asexual reproduction in plants where new plants grow from the non-sexual parts of a parent plant, such as roots, stems, leaves, or buds. This means new plants are clones of the parent. For example, sweet potatoes reproduce from their roots, and strawberries spread using specialized stems called runners. This is an efficient way for many plants to multiply.
In simple words: Vegetative propagation is when plants grow new ones from parts like roots or stems, not seeds. Sweet potatoes grow from roots, and strawberries grow from stems.

🎯 Exam Tip: Clearly define vegetative propagation and provide distinct examples for different plant parts, such as roots (sweet potato) and stems (strawberry).

 

Question 6. What could be the reasons for adopting contraceptive methods?
Answer: Contraceptive methods are adopted for several important reasons:
1. They help avoid frequent pregnancies, which in turn helps control population growth and allows families to plan their size.
2. They prevent the spread of sexually transmitted diseases (STDs), protecting individuals from infections. Family planning also allows couples to space out births, benefiting the health of both mother and child.
In simple words: People use contraceptives to avoid getting pregnant too often and to stop the spread of diseases from sex.

🎯 Exam Tip: The two main reasons for adopting contraceptive methods are population control (spacing pregnancies) and prevention of sexually transmitted diseases.

 

Question 7. State in brief the function of the following organ:
(a) Ovary
(b) Fallopian tube
Answer:
(a) Ovary - The ovary produces oocytes (egg cells) needed for fertilization. It also produces important female hormones like estrogen and progesterone, which control the menstrual cycle and pregnancy.
(b) Fallopian tube - The fallopian tube is responsible for transporting the egg cell from the ovary to the uterus. Fertilization usually happens within the fallopian tube. It acts as a passageway for the egg.
In simple words: The ovary makes eggs and female hormones. The fallopian tube carries the egg from the ovary to the uterus.

🎯 Exam Tip: For each organ, state its primary product (eggs, hormones) and its key action (transporting eggs, site of fertilization).

 

Question 8. Surgical methods can be used to create a block in the reproductive system for contraceptive purpose. Name such parts where block are created in
(i) Male
(ii) Female.
Answer:
(i) Male - In males, a block is created in the vas deferens through a procedure called vasectomy. This prevents sperm from being released.
(ii) Female - In females, a block is created in the fallopian tubes through a procedure called tubectomy. This stops eggs from traveling to the uterus and prevents sperm from reaching the egg. Both methods are permanent forms of contraception.
In simple words: In males, the vas deferens are blocked (vasectomy). In females, the fallopian tubes are blocked (tubectomy).

🎯 Exam Tip: Accurately name the procedure and the specific part blocked for both male (vasectomy-vas deferens) and female (tubectomy-fallopian tubes) surgical contraception.

VIII. Long Answer Questions

 

Question 1. List out the different methods of contraceptive. Explain any two.
Answer: Common contraceptive methods used to prevent pregnancy are:
(i) Barrier methods
(ii) Hormonal methods
(iii) Intra-Uterine Devices (IUDs)
(iv) Surgical methods

Explanation of two methods:
(i) Barrier Methods: These methods physically prevent sperm from meeting the ovum. They create a barrier that blocks the entry of sperm into the female reproductive tract. Examples include condoms and diaphragms. Condoms also offer protection against sexually transmitted diseases.
(ii) Hormonal Methods: These involve hormonal preparations, such as birth control pills or tablets. These hormones work by interfering with ovulation, meaning they stop the release of an egg from the ovary. They can also thicken cervical mucus, making it harder for sperm to reach the egg. Hormonal methods require consistent use to be effective.
In simple words: Contraceptives include barrier methods (like condoms that block sperm), hormonal methods (like pills that stop eggs from releasing), IUDs, and surgical methods. Barrier methods physically stop sperm, and hormonal methods change the body's hormones to prevent ovulation.

🎯 Exam Tip: List at least four categories of contraceptive methods and then provide detailed explanations for two, covering their mechanism of action and examples.

 

Question 2. Explain the structure of pollen grain with a labelled diagram.
Answer: A pollen grain is typically spherical and has two main layers forming its wall. The hard outer layer is called the exine, which often has distinct openings known as germ pores. Inside, there's a thin, continuous inner layer called the intine, made of cellulose and pectin. Mature pollen grains contain two cells: a larger vegetative cell with a big nucleus, and a smaller generative cell. The generative cell later divides to form two male gametes. This structure helps protect the genetic material and enables fertilization.

In simple words: A pollen grain has a tough outer skin (exine) and a soft inner skin (intine). Inside, it has a big cell (vegetative nucleus) and a smaller cell (generative nucleus) that will form sperm.

🎯 Exam Tip: When describing the pollen grain, highlight the exine (outer, protective, with germ pores) and intine (inner) layers, along with the two types of nuclei (vegetative and generative) it contains.

 

Question 3. Write the advantages and disadvantages of self and cross pollination.
Answer:
Advantages of self-pollination:
1. Self-pollination can happen even in certain bisexual flowers, ensuring reproduction.
2. Flowers do not need external agents like insects or wind for pollination.
3. There is less wastage of pollen grains as they don't need to travel far.

Disadvantages of self-pollination:
1. The resulting seeds are often fewer in number.
2. The endosperm (food for the embryo) is very small, leading to weaker plants.
3. New varieties of plants cannot be produced, limiting genetic diversity.

Advantages of cross-pollination:
1. Seeds produced from cross-pollination grow better and stronger, leading to new and improved varieties of plants.
2. More viable and healthy seeds are produced, ensuring better survival rates.

Disadvantages of cross-pollination:
1. Pollination can sometimes fail if the distance between flowers is too great.
2. There is more wastage of pollen grains as many might not reach another flower.
3. It can introduce unwanted traits from other plants.
4. Flowers must depend on external agents (like insects or wind) for pollination to occur.
In simple words: Self-pollination is easy and wastes less pollen, but makes fewer and weaker seeds, with no new plant types. Cross-pollination makes strong new plants with many seeds, but it needs outside help and wastes a lot of pollen.

🎯 Exam Tip: Organize your answer clearly by advantages and disadvantages for both self- and cross-pollination, focusing on seed quality, genetic diversity, and dependence on external factors.

 

Question 4. Explain the structure of human sperm with diagram.
Answer: The human sperm is a microscopic cell with three main parts: a head, a middle piece, and a tail. The head is elongated and contains the nucleus, which carries the genetic material. At the tip of the head is a cap-like structure called the acrosome, which contains enzymes (like hyaluronidase) that help the sperm enter the egg during fertilization. A short neck connects the head to the middle piece. The middle piece is packed with mitochondria, providing the energy needed for the tail's movement. The tail is long and whip-like, allowing the sperm to swim towards the egg. This unique structure ensures efficient delivery of male genetic material.

In simple words: A sperm has a head with genetic material and a cap (acrosome) to help enter the egg. It has a middle part for energy and a long tail to swim.

🎯 Exam Tip: Clearly label the head (with nucleus and acrosome), middle piece (with mitochondria), and tail, explaining the function of each part for motility and fertilization.

 

Question 5. Explain the structure of ovum with diagram.
Answer: The mature ovum, or egg cell, is generally spherical and contains very little yolk. It is surrounded by three protective layers. The innermost layer, directly covering the plasma membrane of the ovum, is the zona pellucida, which is a thin, clear membrane. Outside this, there's a thick layer of follicle cells called the corona radiata. The space between the zona pellucida and the plasma membrane is known as the perivitelline space. The ovum's large nucleus, containing the female genetic material, is also clearly visible. These layers protect the egg and play roles in fertilization.

In simple words: An ovum (egg) is round with a central nucleus. It has three outer layers: the inner zona pellucida and the outer corona radiata made of cells.

🎯 Exam Tip: For the ovum, focus on the concentric layers: plasma membrane, zona pellucida, and corona radiata, and mention the nucleus. The perivitelline space is also an important detail.

IX. Give Reason:

 

Question 1. If a women is using copper - T, will it help in protecting her from sexual transmitted diseases?
Answer: No, a Copper-T will not protect a woman from sexually transmitted diseases (STDs). The Copper-T is an intrauterine device (IUD) that works by preventing a fertilized egg from implanting in the uterus, thus preventing pregnancy. It does not create a barrier against pathogens or microorganisms that cause STDs. The only effective method to prevent the transmission of sexually transmitted diseases is the use of condoms. This highlights the importance of understanding the specific functions of different contraceptive methods.
In simple words: No, a Copper-T only stops pregnancy, it does not stop sexually transmitted diseases. Condoms are the only way to prevent STDs.

🎯 Exam Tip: Clearly state that Copper-T prevents pregnancy (implantation) but does NOT protect against STDs, emphasizing that condoms are required for STD prevention.

 

Question 2. Leaves of the Bryophyllum fallen on the ground produce new plants whereas the leaves of rose do not. Why?
Answer: Bryophyllum leaves are specialized for vegetative propagation because they are thick, fleshy, and have unique notches along their margins. These notches contain adventitious buds that can develop into new plantlets when the leaf falls on moist soil. In contrast, rose leaves do not have these specialized buds or fleshy structures at their margins, so they cannot produce new plants from fallen leaves. This adaptation allows Bryophyllum to reproduce asexually very effectively.
In simple words: Bryophyllum leaves grow new plants from special buds in their edges when they fall. Rose leaves do not have these buds, so they cannot.

🎯 Exam Tip: The key difference is the presence of adventitious buds in the notches of Bryophyllum leaves, which rose leaves lack.

 

Question 3. The organisms formed by asexual reproduction are considered as clones. Why?
Answer: Organisms produced through asexual reproduction are considered clones because they are genetically identical to their single parent. Asexual reproduction involves only one parent and does not include the fusion of gametes or genetic mixing. Instead, it relies on mitotic cell division, which produces exact copies of the parent's genetic material. Therefore, the offspring are perfect genetic duplicates, or clones. This is different from sexual reproduction, which combines genetic material from two parents.
In simple words: Organisms from asexual reproduction are called clones because they are exact genetic copies of their one parent, made without mixing genes.

🎯 Exam Tip: Define a clone as a genetically identical copy and link it directly to asexual reproduction's characteristics: single parent, no gamete fusion, and mitotic division.

X. Higher Order Thinking Skills (HOTS)

 

Question 1. Organism A needs water to multiply and organism B needs sugar solution to multiply. Identify the organism A and B and their method of Reproduction.
Answer: Organism A is Amoeba, which reproduces through binary fission. Amoeba thrives in water and divides into two identical daughter cells when conditions are favorable. Organism B is Yeast, which reproduces through budding. Yeast grows well in a sugar solution, where a small bud grows out from the parent cell and then detaches to form a new yeast cell. Both are forms of asexual reproduction. These organisms show how different environments support different reproductive strategies.
In simple words: Organism A is Amoeba, which multiplies in water by splitting in half (binary fission). Organism B is Yeast, which multiplies in sugar solution by growing small bumps (budding).

🎯 Exam Tip: For each organism, correctly identify it, its specific reproductive method, and the environmental factor it needs to multiply.

 

Question 2. If ovaries from a pregnant woman are removed in 4th month of pregnancy. What will happen?
Answer: If the ovaries of a pregnant woman are removed in the 4th month of pregnancy, the pregnancy would likely continue normally until birth. This is because, by the 4th month, the placenta has usually developed enough to take over the production of progesterone. Progesterone is the hormone essential for maintaining the uterine lining and preventing uterine contractions that could lead to miscarriage. Therefore, the embryo would continue to develop and grow in the uterus until full term. This demonstrates the crucial role of the placenta in later pregnancy.
In simple words: If a pregnant woman's ovaries are removed in the 4th month, the baby will still grow normally. By then, the placenta takes over making the hormones needed to keep the pregnancy going.

🎯 Exam Tip: The key point is that the placenta takes over progesterone production by the 4th month, ensuring the continuation of the pregnancy even without the ovaries.

 

Question 3. A pregnant female not able to delivers the baby due to lack of 'X' hormones. Identify 'X' hormone. Write its function.
Answer: The 'X' hormone is oxytocin. Oxytocin is a hormone produced in the posterior pituitary gland. Its main function during childbirth is to stimulate strong contractions of the uterine muscles. These contractions are necessary to push the baby out of the uterus. Without enough oxytocin, the uterine contractions would be too weak, making it difficult or impossible for the pregnant female to deliver the baby naturally. This hormone also plays a role in milk ejection after birth.
In simple words: The 'X' hormone is oxytocin. It helps the uterus squeeze strongly to push the baby out during birth.

🎯 Exam Tip: Identify oxytocin as the hormone and state its primary function: stimulating uterine contractions during childbirth to expel the baby.