RBSE Solutions Class 12 Biology Chapter 32 Man-Fertilization

Rajasthan Board RBSE Class 12 Biology Chapter 32 Man-Fertilization

RBSE Class 12 Biology Chapter 32 Multiple Choice Questions

Question 1. Significance of fertilizin and antifertilizin in fertilization is -
(a) Attract gametes
(b) Protection of spermatozoa
(c) attachment of the sperms on the ovum surface
(d) All of the options
Answer: (c) attachment of the sperms on the ovum surface
In simple words: Fertilizin and antifertilizin are important chemicals that help sperms stick to the egg's surface during fertilization, ensuring they connect properly.

🎯 Exam Tip: Remember that fertilizin is on the ovum and antifertilizin is on the sperm; their interaction is key for species-specific recognition and attachment.

Question 2. Fertilization is -
(a) Fusion of male and female pronuclei
(d) All of the options
Answer: (c) Fusion of ♂ & ♀ gametes of the same species
In simple words: Fertilization is when a male reproductive cell and a female reproductive cell from the same type of living thing join together.

🎯 Exam Tip: While pronuclei fusion is a part of fertilization, the broader definition emphasizes the fusion of gametes to form a zygote.

Question 3. Which part of sperm head comes in the contact with egg at the time of fertilization?
(a) Acrosome
(b) Acromegaly
(c) Acronis
(d) Anterior lobe
Answer: (a) Acrosome
In simple words: The acrosome, found at the tip of the sperm's head, is the first part to touch the egg during fertilization. It helps the sperm get inside.

🎯 Exam Tip: The acrosome contains enzymes that digest the egg's outer layers, a crucial step for successful fertilization.

Question 4. An enzyme secreted by the anterior lobe of sperm is -
(a) Hyaluronidase
(b) Pepsin
(d) D. Hydronidase
Answer: (a) Hyaluronidase
In simple words: Hyaluronidase is an enzyme released by the sperm that helps it break through the outer protective layers of the egg.

🎯 Exam Tip: Hyaluronidase helps clear a path through the hyaluronic acid matrix in the egg's cumulus oophorus, allowing the sperm to reach the zona pellucida.

Question 5. Capacity for fertilization appears in the human sperm when sperms reach in the vagina. This activity is called -
(a) Cortical reaction
(b) Capacitation
(c) Acrosome reaction
(d) Meeting of sperm and ovum
Answer: (b) Capacitation
In simple words: When sperm enter the female body, they go through a process called capacitation, which makes them able to fertilize an egg.

🎯 Exam Tip: Capacitation is a series of physiological changes in the sperm that increases its motility and makes it responsive to signals from the egg, allowing the acrosome reaction to occur.

Question 7. Site of fertilization in female human is -
(a) Vagina
(b) Seminal vesicles
(c) Uterus
(d) Fallopian tubes
Answer: (d) Fallopian tubes
In simple words: In women, fertilization usually happens in the fallopian tubes, which are the tubes connecting the ovaries to the uterus.

🎯 Exam Tip: Fertilization typically occurs in the ampulla, the wider part of the fallopian tube, after the egg is released from the ovary.

Question 8. Fertilizin is secreted by -
(a) Ovum
(b) Spermatid
(d) Ovary
Answer: (a) Ovum
In simple words: Fertilizin is a substance released by the egg (ovum) that helps attract and attach sperm.

🎯 Exam Tip: Fertilizin is a glycoprotein that plays a role in species-specific recognition, ensuring that sperm from the correct species fertilize the egg.

Question 9. Spermatozoan moves by -
(a) Tail
(b) Head
(c) Acrosome
(d) Middle part
Answer: (a) Tail
In simple words: Sperm move by using their tail, which whips back and forth, pushing them forward like a tiny propeller.

🎯 Exam Tip: The tail, or flagellum, is powered by mitochondria located in the mid-piece of the sperm, providing the energy for movement.

RBSE Class 12 Biology Chapter 32 Very Short Answer Type Questions

Question 1. Who has given the concept of fertilizin?
Answer: F.R. Lillie.
In simple words: F.R. Lillie was the scientist who first explained the idea of fertilizin.

🎯 Exam Tip: For scientific discovery questions, remember the key scientist and the concept they introduced.

Question 2. Where fertilizin is present?
Answer: The surface of the ovum.
In simple words: Fertilizin is found on the outer layer of the egg.

🎯 Exam Tip: Knowing the location of fertilizin helps understand its role in sperm-egg interaction and recognition.

Question 3. Who has studied acrosome reaction?
Answer: Colwin, 1963.
In simple words: The acrosome reaction was studied by Colwin in 1963.

🎯 Exam Tip: Mentioning the scientist and year demonstrates precise knowledge in biology.

Question 4. Define fertilization.
Answer: The fusion of male gamete (sperm) and female gamete (ovum) is called fertilization.
In simple words: Fertilization is when a male sperm and a female egg join together.

🎯 Exam Tip: A good definition includes both the agents (sperm and ovum/gametes) and the process (fusion).

Question 5. What is Amphimixis?
Answer: This process involves karyogamy (fusion of male and female pronuclei) and plasmogamy (fusion of cytoplasm of ovum and sperm).
In simple words: Amphimixis is when the genetic material (nuclei) and the cell fluids (cytoplasm) from the male and female reproductive cells mix together.

🎯 Exam Tip: Differentiate between karyogamy (nuclear fusion) and plasmogamy (cytoplasmic fusion) to fully explain amphimixis.

Question 7. What is ovum activation?
Answer: Ovum activation involves the Cortical Reaction, which starts immediately after a sperm enters the egg. This reaction prevents other sperms from entering. Chemicals from cortical granules are released between the plasma membrane and vitelline membrane, forming a fertilization membrane. This membrane makes sure no more sperm can get in. After activation, several metabolic changes happen within the ovum, including:
• Fertilization cone is formed on the egg surface.
• Fertilization membrane is formed by the vitelline membrane and cortical granules.
• Mitotic divisions start in the fertilized egg.
In simple words: Ovum activation is a process where the egg undergoes changes right after one sperm enters it. These changes stop other sperms from getting in and prepare the egg for development, like forming a protective layer and starting cell division.

🎯 Exam Tip: Focus on the two main aspects of ovum activation: preventing polyspermy and initiating embryonic development.