GSEB Class 7 Science Solutions Chapter 12 વનસ્પતિમાં પ્રજનન

Textbook Exercise Questions and Answers

1. Fill in the blanks:

Question 1. The process of forming a new plant from the vegetative part of a plant is called ____________.
Answer: Vegetative reproduction
In simple words: When a new plant grows directly from a part of an existing plant, like its stem or leaf, it's known as vegetative reproduction.

Exam Tip: Remember that vegetative reproduction doesn't involve seeds or spores, but uses parts like roots, stems, or leaves to grow new plants.

Question 2. A flower that has either male or female reproductive organs is called ____________.
Answer: Unisexual flower
In simple words: A flower with only male parts or only female parts is called a unisexual flower.

Exam Tip: Differentiate between unisexual flowers (having only male or female reproductive parts) and bisexual flowers (having both). This distinction is key for understanding pollination.

Question 3. The process of transferring pollen grains from the anther of a flower to the stigma of the same flower or another flower on another plant is called ____________.
Answer: Pollination
In simple words: Pollination is the movement of pollen from the male part of a flower to the female part, either on the same flower or a different one.

Exam Tip: Understanding the two types of pollination – self-pollination and cross-pollination – is crucial for describing this process fully.

Question 4. The process of fusion of male and female gametes is called ____________.
Answer: Fertilization
In simple words: When male and female reproductive cells join together, it is called fertilization.

Exam Tip: Remember that fertilization is a critical step in sexual reproduction, leading to the formation of a zygote and subsequently, a new organism.

Question 5. Seed dispersal can occur through ____________ and ____________.
Answer: Wind, water, animals
In simple words: Seeds can be spread to new places by air currents, flowing water, or living creatures.

Exam Tip: When listing agents of dispersal, always try to give at least three examples to show a broad understanding of the different mechanisms.

Question 2. Explain the different methods of asexual reproduction with examples.
Answer: The various methods of asexual reproduction, with examples, are as follows:
(1) **Cutting:** When a branch of a rose or hibiscus plant is cut from its node and planted in the ground, a new plant grows from it. The piece used is called a cutting, and this method is termed 'cutting'. Rose, hibiscus, henna, and other plants can be grown by rooting cuttings. This process is considered an artificial method of vegetative propagation.
(2) **By Buds:** In this method of vegetative reproduction, a new plant can develop from buds present on roots, stems, and leaves.
* **Vegetative reproduction by roots:** For example, sweet potato, carrot, dahlia.
* **Vegetative reproduction by stems:** For example, potato, ginger, turmeric, yam.
* **Vegetative reproduction by leaves:** For example, Bryophyllum (Paanfutti).
Some plants, like cacti, can produce a new plant if a part separates from the main plant.
(3) **Budding:** Yeast is a single-celled organism that reproduces asexually through budding. A small, bulb-like projection, called a bud, emerges from the yeast cell. This bud slowly grows and detaches from the parent cell to form a new, independent organism. The new cell then grows and matures, producing more yeast cells. (Refer to the diagram for Activity 3 in the Activity section.)
(4) **Fragmentation:** A green mass found in pond water is Spirogyra algae. These algae grow when they get water and nutrients. They are autotrophic plants that multiply very rapidly through fragmentation. The algal filament breaks into two or more pieces. Each new filament develops as an individual organism. Asexual reproduction occurs in Spirogyra (a type of algae) by fragmentation.
(5) **Spore Formation:** Spores are produced in the sporangia of fungi. These spores are released and float in the air. When they find favorable conditions, they germinate and rapidly grow into a fungal mycelium. Fungi like Mucor and fern (Nephrolepis) reproduce asexually through spore formation.
In simple words: Asexual reproduction involves making new plants from a single parent without seeds. Methods include taking a piece of a plant and growing it (cutting), new plants growing from special buds on leaves or stems, tiny yeast cells forming smaller 'buds' that break off, and simple plants like algae breaking into pieces to grow new ones. Fungi also make tiny spores that grow into new fungi.

Exam Tip: When explaining methods of asexual reproduction, always provide a clear definition of the process and at least one relevant plant example for each method. Mentioning if it's natural or artificial also adds value.

Question 3. Describe what you understand by sexual reproduction.
Answer: In sexual reproduction, the fusion of male and female gametes is necessary. In a flower, the stamen is the male reproductive organ, and the pistil is the female reproductive organ. Pollen grains produced in the anther of the stamen contain male gametes. The ovules in the ovary of the pistil contain female gametes. When pollen grains from the stamen fall on the stigma of the pistil, the male and female gametes unite to form a zygote. This is sexual reproduction in flowering plants. [Sexual reproduction also occurs in animals. Male animals produce male gametes (sperm cells), and female animals produce female gametes (egg cells). The fusion of male and female gametes forms a zygote.]
In simple words: Sexual reproduction needs both male and female cells to join together. In flowers, pollen from the male part meets the egg in the female part. This joining makes a new seed. Animals also use this method, where sperm and egg cells combine.

Exam Tip: For sexual reproduction, clearly identify the male and female reproductive parts in both plants (stamen, pistil) and animals (sperm, egg) and emphasize the fusion of gametes (fertilization) as the key event.

Question 4. Give the difference between asexual and sexual reproduction.
Answer:

Exam Tip: When comparing, always use clear, contrasting points for each characteristic to ensure full marks. Focus on the number of parents, gametes, and genetic similarity of offspring.

Question 5. Draw and explain the reproductive organs of a flower with a diagram.
Answer: The male reproductive organ of a flower is the stamen, and the female reproductive organ is the pistil.
*(Diagrams of the Stamen and Pistil were present in the source material. These illustrate the parts mentioned below.)*
**[Figure 12.2: Reproductive Organs of a Flower]**
**Stamen (Male Reproductive Organ):** It has two main parts:
* **Anther:** This is the top part that produces pollen grains, which contain the male gametes.
* **Filament:** This is a thin stalk that supports the anther.
**Pistil (Female Reproductive Organ):** It has three main parts:
* **Stigma:** This is the sticky top part that receives pollen grains.
* **Style:** This is a tube-like structure connecting the stigma to the ovary.
* **Ovary:** This is the swollen base containing ovules, which hold the female gametes. After fertilization, the ovary develops into a fruit, and the ovules become seeds.
In simple words: A flower's reproductive parts are the stamen (male) and the pistil (female). The stamen makes pollen, and the pistil takes pollen to grow seeds inside.

Exam Tip: When asked to draw and explain, draw neat, labeled diagrams. For explanation, clearly describe the parts of both the stamen and pistil and their functions in reproduction.

Question 6. Give the difference between self-pollination and cross-pollination.
Answer:

Exam Tip: Highlight the movement of pollen: same flower for self-pollination, and different flowers/plants for cross-pollination. Also, mention the role of external agents in cross-pollination.

Question 7. How does the process of fertilization occur in flowers?
**OR**
**Explain the process of fertilization in flowers by drawing a diagram.**
Answer: The process of pollination involves the transfer of pollen grains from the anther of a stamen to the stigma of the same flower or another flower on another plant. After this, the process of fertilization begins. The pollen grain deposited on the stigma germinates. The ovule then produces a pollen tube, which grows down into the style.
*(Diagrams illustrating fertilization and zygote formation were present in the source material.)*
**[Figure 12.3: Fertilization (Zygote Formation)]**
The pollen tube grows and enters the ovary located below. The male gametes produced in the pollen grain enter the ovule within the ovary and fuse with the female gametes produced in the ovule to form a zygote. This process is called fertilization. After fertilization, the ovary develops into a fruit, and the ovules mature and become seeds.
In simple words: Fertilization in flowers begins after pollen reaches the stigma. A tube grows from the pollen down to the ovary. Inside the ovary, male cells from the pollen join with female cells (ovules). This joining creates a new seed, and the ovary turns into a fruit.

Exam Tip: Explain the journey of the pollen tube from the stigma to the ovule, emphasizing the fusion of male and female gametes as the core event of fertilization. Use terms like pollen, stigma, ovule, ovary, and zygote.

Question 8. Explain various methods of seed dispersal.
Answer: Seed dispersal occurs through wind, water, and animals.
(1) **Dispersal by Wind:** Some plant seeds are small, light, and winged. For example, drumstick (Moringa) and maple. Some plant fruits and seeds are light and hairy. For example, sunflower seeds, madar (Calotropis) seeds. Such seeds fly in the air with the wind and spread far away. Thus, wind helps in seed dispersal.
**[Figure 12.4: Seed Dispersal by Wind]**
(2) **Dispersal by Water:** Seeds of lotus, water lily, and coconut are dispersed by water from one place to another. Thus, their seed dispersal occurs through water.
(3) **Dispersal by Animals:** Some plant seeds have thorns or hooks. When animals pass nearby, these thorny seeds stick to their bodies and are carried to distant places. For example, Xanthium (Gokharu) and Urena (Gadheriyu).
**[Figure 12.5: Urena (Gadheriyu)]**
(4) **Dispersal by Bursting of Fruit:** Some plant seeds dry up, burst open, and scatter far and wide. This is how seed dispersal occurs. For example, peas, balsam, and castor.
In simple words: Seeds spread out in a few ways. Some are light and float on the wind, like dandelion seeds. Others float on water, such as coconut seeds. Some seeds have hooks or thorns that stick to animals, which then carry them to new spots. Lastly, some fruits pop open when dry, throwing their seeds far away.

Exam Tip: When explaining seed dispersal, provide specific examples of seeds/fruits that use each method and describe the adaptations that facilitate that particular mode of dispersal (e.g., wings for wind, hooks for animals).

Question 9. Match the items in Column I with Column II:
**Column I**
(1) Budding
(2) Eye
(3) Fragmentation
(4) Wings
(5) Spore
**Column II**
(a) Maple
(b) Spirogyra
(c) Yeast
(d) Mucor (Bread mould)
(e) Potato
(f) Rose
Answer: (1) → (c), (2) → (e), (3) → (b), (4) → (a), (5) → (d).
In simple words: Matching connects how things reproduce or what they look like. For example, budding with yeast, potato eyes, fragmentation with Spirogyra, maple wings, and spores with bread mold.

Exam Tip: For matching questions, identify the core concept or characteristic associated with each item in Column I and then find its corresponding example or description in Column II. Double-check all pairings.

10. Choose the correct option:

Question 1. The reproductive organ of a plant is ____________.
(a) Leaf
(b) Stem
(c) Root
(d) Flower
Answer: (d) Flower
In simple words: The flower is the part of a plant responsible for making new seeds, which helps the plant to reproduce.

Exam Tip: Understand that while other parts can be involved in vegetative propagation, the flower is the primary organ for sexual reproduction in most plants.

Question 2. Fusion of male and female gametes is called ____________.
(a) Fertilization
(b) Pollination
(c) Reproduction
(d) Seed formation
Answer: (a) Fertilization
In simple words: When a male reproductive cell and a female reproductive cell join together, this specific process is called fertilization.

Exam Tip: Distinguish between pollination (transfer of pollen) and fertilization (fusion of gametes). They are sequential but distinct processes.

Question 3. Mature ovary forms ____________.
(a) Seed
(b) Stamen
(c) Pistil
(d) Fruit
Answer: (d) Fruit
In simple words: Once the ovules inside a flower's ovary are fertilized, the ovary itself grows and becomes what we know as a fruit.

Exam Tip: Remember the development stages: ovules become seeds, and the entire ovary becomes the fruit after fertilization.

Question 4. The plant that reproduces by spore formation is ____________.
(a) Rose
(b) Bread mould (Mucor)
(c) Potato
(d) Ginger
Answer: (b) Bread mould (Mucor)
In simple words: Bread mould, which is a type of fungus, makes new moulds by releasing tiny cells called spores.

Exam Tip: Associate spore formation primarily with fungi and lower plants like ferns, distinguishing it from vegetative propagation in plants like rose, potato, and ginger.

Question 5. Reproduction in Bryophyllum (Paanfutti) occurs through ____________.
(a) Stem
(b) Leaf
(c) Root
(d) Flower
Answer: (b) Leaf
In simple words: New Bryophyllum plants can grow from special buds that form along the edges of its leaves.

Exam Tip: Bryophyllum is a classic example of vegetative propagation via leaves. Remember that small plantlets grow from notches along the leaf margins.

GSEB Class 7 Science: Understanding Textbook Activities

Activity 1: To understand artificial vegetative propagation through stem.
**Materials:** Stem cutting of a rose plant
*(A diagram showing a rose stem cutting with a node was present in the source material.)*
**[Figure: Rose Stem Cutting]**
**Procedure:**
1. Cut a branch of a rose plant from its node. This piece is called a cutting.
2. Plant this cutting in the soil.
3. Water it daily. Observe its growth every day. Node
4. Observe and note how many days it takes for roots to emerge and leaves to grow.
5. Perform the same activity with a money plant (Pothos) by growing it in a glass bottle filled with water and record your observations.
**Observation:** When a cutting is planted, it grows and develops into a new plant.
**Conclusion:** New plants can be formed through vegetative propagation by stems.
In simple words: We learned that taking a small piece of a plant's stem and planting it can make a whole new plant. This is a simple way to grow plants, like roses or money plants.

Exam Tip: When describing an experiment, always clearly state the objective, materials, step-by-step procedure, observations, and a concise conclusion based on the observations.

Activity 2: To understand vegetative propagation through buds.
**Materials:** A fresh potato
*(A diagram showing a potato sprouting from its 'eye' was present in the source material.)*
**[Figure: Potato Plant Sprouting from Eye]**
**Procedure:**
1. Take a fresh potato.
2. Examine the 'eyes' or buds on its surface with a magnifying glass. You will see small buds there. These are also called 'eyes'.
3. Cut the potato into several pieces, ensuring each piece has an 'eye'.
4. Plant these pieces in the soil.
5. Water them daily.
6. Observe the growth that occurs in them.
**Observation:** A plant sprouting from the 'eye' of the potato can be seen.
**Conclusion:** New plants can be created through vegetative propagation by buds.
In simple words: We saw that if you plant pieces of a potato that have 'eyes' (small buds), new potato plants will grow from them. This means buds on a potato can start new plants.

Exam Tip: When performing experiments involving plant parts, ensure that each planted section contains a viable 'bud' or 'eye' for successful propagation. This small detail is vital for the experiment to work.

Activity 3: To understand asexual reproduction through budding in yeast.
**Materials:** Yeast powder, sugar, a vessel filled with water, a glass slide, a microscope.
*(A diagram illustrating the budding process in yeast cells was present in the source material.)*
**[Figure: Reproduction in Yeast by Budding]**
**Procedure:**
1. Take a pinch of yeast and put it in a vessel filled with water.
2. Add one spoonful of sugar to it and stir to dissolve it.
3. Place it in a warm place at room temperature.
4. After an hour, place a drop of this solution on a glass slide and observe it under a microscope. What do you see?
**Observation:** Newly formed yeast cells are observed. In some, buds are seen developing.
**Conclusion:** Reproduction in yeast occurs through budding.
In simple words: We mixed yeast and sugar in warm water, then looked at it closely. We saw new yeast cells growing as small 'buds' coming off the main cells. This showed us how yeast makes more of itself.

Exam Tip: For observing microscopic organisms like yeast, ensure proper microscope usage and slide preparation. The warmth and sugar provide essential conditions for rapid yeast growth and budding.

Activity 4: To observe different parts of stamen and pistil.
**Materials:** A hibiscus flower
**Procedure:**
1. Take a hibiscus flower.
2. Separate its reproductive organs.
3. Observe the parts of its stamen and pistil.
*(A diagram showing the parts of a stamen and a pistil was present in the source material.)*
**[Figure: Stamen and Pistil]**
**Observation:** The parts of the stamen are the anther and filament. The parts of the pistil are the stigma, style, and ovary.
**Conclusion:** A hibiscus flower is a bisexual flower; it has both stamen and pistil.
In simple words: We looked at a hibiscus flower closely and found its male part (stamen) and female part (pistil). This means the hibiscus has both male and female reproductive organs in one flower.

Exam Tip: When dissecting a flower, carefully separate the parts to avoid damage. Clearly identify and label each part of the stamen and pistil, understanding their role in the reproductive process.