Class 12 Biology MCQ – Sexual Reproduction


This set of Class 12 Biology Chapter 1 Multiple Choice Questions & Answers (MCQs) focuses on “Sexual Reproduction”.

1. What is sexual reproduction?
a) Fusion of male and female gamete
b) Fusion of male and male gamete
c) Fusion of female and female gamete
d) Either a male or a female gamete
View Answer

Answer: a
Explanation: The fusion of a haploid male (23 chromosomes) and a haploid female gamete (23 chromosomes) produces a diploid (46 chromosomes) egg or a zygote. This process of reproduction is known as sexual reproduction.

2. What is phase when the organism is old enough to reproduce known as?
a) Juvenile phase
b) Vegetative phase
c) Senescence
d) Reproductive phase
View Answer

Answer: d
Explanation: The phase when it is growing is known as the juvenile phase or the vegetative phase (in plants). The phase after that when the reproductive organs in the organism matures is known as the reproductive phase. Senescence is the phase when the plant starts deteriorating as it grows old and finally dies.

3. In which plant species is it difficult to define the different phases (juvenile, reproductive phase)?
a) Biennial
b) Annual
c) Perennial
d) Seasonal
View Answer

Answer: c
Explanation: It is difficult to clearly distinguish between the different phases in perennial plants. Some plants exhibit unusual flowering phenomena. Some plants flower every year, there are some that flower every 10 years and some plants flower every 50 years. Neelakurinji is a flowering plant that flowers every 12 years.
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4. Which type of plants flower only once?
a) Monocarpic
b) Polycarpic
c) Vivipary
d) Unocarpic
View Answer

Answer: a
Explanation: Monocarpic plants flower only once in its lifetime. They die after flowering. Annuals like marigold, wheat, paddy, biennials like radish, perennials like Bambusa tulda which flowers every 50-100 years, fruits and dies.

5. Which type of plant flowers repeatedly?
a) Polypary
b) Vivipary
c) Polycarpic
d) Monocarpic
View Answer

Answer: c
Explanation: Polycarpic plants are those that flower repeatedly, which means they do not die after flowering once. Examples are perennials like apple, mango and perennial flowers like china rose, it flowers throughout the year.

6. What are the 3 phases in a life cycle (in order)?
a) reproductive, senescence, juvenile
b) juvenile, senescence, death
c) reproductive, senescence, death
d) juvenile, reproductive, senescence
View Answer

Answer: d
Explanation: There are 3 phases in a life cycle.
i. Juvenile phase/ vegetative phase: period from birth to maturation of reproductive systems.
ii. Reproductive phase: period when the reproductive systems have matured and ready to produce offspring.
iii. Senescence: period when the organism starts growing old and starts degrading.

7. Name the sequence in which sexual reproduction is divided into?
a) fertilization, post-fertilization, reproduction
b) pre-fertilization, fertilization, post-fertilization
c) pre-fertilization, fertilization, reproduction
d) pre-fertilization, post-fertilization, fertilization
View Answer

Answer: b
Explanation: Sexual reproduction is the fusion of the male and the female gamete that forms a single celled zygote, the process is known as fertilization. This process has been divided into 3 events. The pre-fertilization, fertilization and post-fertilization events.

8. Which factor is responsible for the changes in the 3 phases in a life cycle?
a) Blood
b) Hormones
c) Respiration
d) Nervous system (in animals)
View Answer

Answer: b
Explanation: Hormones are chemical messengers that travel through the bloodstream (in case of animals). Hormones are responsible for the change in the phases in both plants and animals. Hormonal change can be affected by environmental factors too.

9. What process does the image show?
Fertilization is process of fusion of male & female gamete to form an egg or a zygote
a) Parthenogenesis
b) Fertilization
c) Torrulation
d) Sporolation
View Answer

Answer: b
Explanation: Fertilization is the process of fusion of the male and female gamete to form an egg or a zygote. It is a type of sexual reproduction. Formation of a diploid cell from 2 haploid cells.

10. Sexual reproduction is a fast process.
a) False
b) True
View Answer

Answer: a
Explanation: Sexual reproduction, unlike asexual reproduction is a slow process. Since it is the fusion of 2 opposite sex gametes, it produces variations better than the parent. The time period varies from specie to specie.

Sanfoundry Global Education & Learning Series – Biology – Class 12.

To practice all chapters and topics of class 12 Biology, here is complete set of 1000+ Multiple Choice Questions and Answers.

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