Reproduction in Organisms - NEET Biology Important Questions

Reproduction in organisms is the first Chapter of Class 12. It covers the basics of sexual and asexual reproduction in organisms. Here, let’s glance at some important questions from this Chapter for the NEET exam.

1. Which of the following is not true about reproduction?

1. Reproduction is defined as a biological process in which an organism gives rise to young ones (offspring) similar to itself
2. When two parents (opposite sex) participate in the reproductive process, it is called sexual reproduction
3. Reproduction enables the continuity of the species, generation after generation
4. Reproduction always results in genetically identical offspring

Answer: d. Reproduction always results in genetically identical offspring

Discussion: Reproduction is a biological process in which an organism gives rise to young ones (offspring). These offspring then grow, mature and perform reproduction to produce new offspring. Reproduction enables the continuity of the species, generation after generation.

Reproduction is of 2 types –

1. Asexual reproduction – offspring are produced by a single parent and thus they are genetically identical.
2. Sexual reproduction – two parents of opposite gender participate in the reproductive process and they create genetically unique offspring.

2. Which of the following reproduce by binary fission?

1. Amoeba
2. Spongilla
3. Yeast
4. Hydra

Answer: a. Amoeba

Discussion: Binary fission in amoeba is a process in which a parent cell splits into 2 daughter cells of approximately equal size. These daughter cells further grow into adults.

Binary Fission in Amoeba

Budding in yeast is an unequal division. A small bud attached to the parent body develops into an adult. Hydra also shows budding. Here, the bud grows externally whereas, in sponges, the bud is formed within the parents. These buds are called gemmules.

Budding in Yeast

Budding in Hydra

3. Under unfavourable conditions, amoeba withdraws its pseudopodia and secretes a three-layered hard covering or cyst around itself. This phenomenon is termed as ⸻.

1. Fragmentation
2. Encystation
3. Sporulation
4. Budding

Answer: b. Encystation

Discussion: Under favourable conditions, the parent amoeba divides into many minute amoeba (pseudopodiospores). This process is called sporulation. During this process, the cyst bursts and releases these pseudopodiospores.

4. Sea stars are broken apart by workers to save the clams they feed on, and then thrown back into the ocean. Often the number of sea stars are seen to double after this. Choose the reason why this happens.

1. Regeneration
2. Fragmentation
3. Budding
4. Presence of suitable conditions

Answer: a. Regeneration

Discussion: The regrowth of a lost body part or tissues or a complete organism is called regeneration. Every living organism is capable of regeneration up to an extent.

5. Clones are ⸻

1. Morphologically identical but genetically different
2. Genetically identical but morphologically different
3. Morphologically and genetically identical
4. Genetically and morphologically different

Answer: c. Morphologically and genetically identical

Discussion: Clones are organisms or cells that are genetically and morphologically identical. The offspring that are produced by asexual reproduction are not only identical to one another but are also exact copies of their parent.

6. ⸻ arise from the notches present at the margins of leaves of Bryophyllum.

1. Adventitious buds
2. Tuber
3. Axillary buds
4. Bulb

Answer: a. Adventitious buds

Discussion: Adventitious buds grow out of different places other than the apex of the plant or the axil of the leaf. They serve as vegetative propagules. In Bryophyllum, the adventitious buds on marginal notches of leaves can form plantlets.

7. Which of the following statements is true about gemmules?

1. They are endogenous spores
2. They are exogenous spores
3. They are seen in Penicillium
4. They are seen in amoeba

Answer: a. They are endogenous spores

Discussion: Spores that are produced within the body of an organism are termed endogenous spores. For example – gemmules in sponges. Likewise, spores that are produced outside the body of an organism are termed exogenous spores. For example – conidiospores in Penicillium.

8. The most invasive weed called the ‘Terror of Bengal’ is ⸻.

1. Pistia stratiotes
2. Water lettuce
3. Water hyacinth
4. Nelumbo nucifera

Answer: c. Water hyacinth

Discussion: Water hyacinth is a very rapidly growing weed. It was introduced in India because of its beautiful flowers and the shape of its leaves. However, it drained the oxygen from the water, which led to the death of fishes. This coupled with the fact it can propagate vegetatively at a phenomenal rate and spread all over the water body in a short period of time, makes it a very troublesome organism.

9. Which of the following is not a vegetative propagule?

1. Tuber
2. Zoospore
3. Bulbil
4. Sucker

Answer: b. Zoospore

Discussion: Zoospores are microscopic motile asexual structures produced by Chlamydomonas (green algae) for reproduction. It is not a vegetative propagule whereas tuber, sucker and bulbil are vegetative propagules.

10. Why is sexual reproduction useful?

1. It completes in a very short period of time
2. It results in the rapid production of many offspring
3. It increases genetic diversity, allowing organisms to survive in an unpredictable environment
4. It needs less energy and leads to genetic variation in the offspring

Answer: c. It increases genetic diversity, allowing organisms to survive in an unpredictable environment

Discussion: As mentioned earlier, asexual reproduction results in genetically identical offspring, whereas sexual reproduction results in genetically unique offspring. In sexual reproduction, a male gamete and female gamete fuse and fertilise to form a zygote.

11. Embryos lack a placental connection to the oviduct or uterus in

1. Viviparous animals only
2. Oviparous animals only
3. Ovoviviparous animals only
4. Oviparous and ovoviviparous animals

Answer: d. Oviparous and ovoviviparous animals

Discussion

12. Which among the following can be considered as a sign of a senescent phase in humans?

1. Slowing of metabolism
2. End of reproductive phase
3. No increase in height
4. Only 2
5. Both 2 and 3
6. Both 1 and 2
7. Both 1 and 3

Answer: c. Both 1 and 2

Discussion: The three notable phases in organisms are –

1. Juvenile phase – This is the growing phase
2. Reproductive phase – This phase varies widely in animals. Morphological and physiological changes can be observed along with active reproductive behaviour.
3. Senescent phase – In this phase, they cannot reproduce. The organism grows old and weak.

Senescent phase in humans – This is typically the last phase of life cycle in humans. This is marked by the end of the reproductive phase. Another notable change would be the slowing of metabolism. Increase in height is also limited during this phase. It stops after a certain age much before the senescent phase. Hence, it is not considered as a sign of a senescent phase in humans.

13. Which of the following pairs is not correctly matched?

1. Rice – Monocarpic
2. Apple – Polycarpic
3. Grape vine – Polycarpic
4. Orange – Monocarpic

Answer: d. Orange – Monocarpic

Discussion: Polycarpic plants are perennial plants and flower repeatedly in intervals every year. Examples – apple, orange, grapevine and mango are perennial polycarpic plants.

Monocarpic plants are plants that flower only once in their entire lifetime. After flowering, they produce fruits and then they die. All annual plants like wheat, rice and biennial plants like radish, and carrot are monocarpic.

See more:Difference between Parthenocarpy and Parthenogenesis

14. Select the correct statement as to why internal fertilisation is advantageous over external fertilisation.

1. Internal fertilisation leads to more genetic variations and increases the survival rates of offspring
2. internal fertilisation increases the survival rates of offspring, and large numbers of offspring are produced
3. Internal fertilisation increases the survival rates of offspring, and the chances of fertilisation with a specific partner also increase
4. Internal fertilisation increases the survival rates of offspring and decreases the chance of fertilisation with a specific partner

Answer: c. Internal fertilisation increases the survival rates of offspring, and the chances of fertilisation with a specific partner also increase.

Discussion: Fertilisation is of 2 types – internal and external. The probability of genetic variation is the same in both external and internal fertilisation.

15. Correct progression of events in sexual reproduction is

1. Gametogenesis ► Fertilisation ► Gamete transfer ► Embryogenesis ► Zygote formation
2. Gametogenesis ► Gamete transfer ► Fertilisation ► Zygote formation ►Embryogenesis
3. Fertilisation ► Gamete transfer ► Gametogenesis ► Zygote formation ► Embryogenesis
4. Gamete transfer ► Fertilisation ► Gametogenesis ► Embryogenesis

Answer: b. Gametogenesis ► Gamete transfer ► Fertilisation ► Zygote formation ►Embryogenesis

Discussion: The events of sexual reproduction are grouped into 3 phases –

1. Pre-fertilisation – gametogenesis and gamete transfer
2. Fertilisation – fusion of female and male gametes
3. Post fertilisation – embryogenesis

• Gametogenesis is the first step of the pre-fertilisation events. In this process, haploid male and female gametes are formed.
• Gamete transfer happens after the formation of gametes. They have to be physically brought together to facilitate fertilisation/fusion.
• Then happens the fertilisation process where the male and female gametes fuse.
• The further growth and development of the zygote happen through the different stages of embryogenesis and growth to a complete individual comprises the post-fertilisation events.

Also Check:Difference between Gametogenesis and Embryogenesis

16. Male gametes in diploid maize plants have 10 chromosomes in their nucleus. What would be the number of chromosomes in its female gamete, zygote and the cells of the seedling, respectively?

1. 20, 10, 10
2. 10, 20, 20
3. 10, 10, 10
4. 10, 10, 20

Answer: b. 10, 20, 20

Discussion: Chromosome number in male gametes is 10. Therefore, the number of chromosomes in female gametes will also be 10. Since the plant is diploid, the zygote will be 2n. Here, n is the number of chromosomes in the haploid set. As it is formed from the fusion of two haploid gametes 2n= 2 ✕ 10 = 20.

Seedlings are the product of division and differentiation of zygote so it will also be diploid which here is 20.

17. Match the following (column 1 with column 2).

1. p-4, q-3, r-2, s-1
2. p-2, q-1, r-4, s-3
3. p-3, q-4, r-2, s-1
4. p-4, q-3, r-1, s-2

Answer: a. p-4, q-3, r-2, s-1

Discussion

18. Read and select the correct option

Statement 1: Unisexual flowers are either staminate or pistillate flowers

Statement 2: Both monoecious and dioecious plants have unisexual flowers

1. Both statements 1 and 2 are correct and statement 2 is the correct explanation of statement 1
2. Both statements 1 and 2 are correct but statement 2 is not the correct explanation of statement 1
3. Statement 1 is correct and statement 2 is incorrect
4. Both statements are incorrect

Answer: b. Both statements 1 and 2 are correct but statement 2 is not the correct explanation of statement 1

Discussion: Angiosperms can be classified into 2 – monoecious and dioecious

19. The phenomenon by which a female gamete develops into a new organism without fertilisation is called ⸻.

1. Syngamy
2. Parthenogenesis
3. Gametogenesis
4. Embryogenesis

Answer: b. Parthenogenesis

Discussion: An organism can develop from the female gametes, without fertilisation. This process is called parthenogenesis. It is seen in certain organisms like rotifers, aphids and honey bees.

20. In which of the following organisms does the oestrus cycle not take place?

1. Lion
2. Rabbit
3. Rat
4. Monkey

Answer: d. Monkey

Discussion: Estrus cycle or oestrus cycle takes place in non-primate females. Rabbit, lion and rat are non-primates. Whereas, in primates (monkeys) only the menstrual cycle takes place. Both these cycles are referred to as the set of cyclical changes that take place during the reproductive phase.

Do check important NEET notes for the Chapter Reproduction in Organisms. Explore similar NEET-related contents, only at BYJU’S.

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