Chapter 1

Reproduction in Organisms

MULTIPLE-CHOICE QUESTIONS

1. A few statements describing certain features of reproduction are given below:

i. Gametic fusion takes place

ii. Transfer of genetic material takes place

iii. Reduction division takes place

iv. Progeny have some resemblance with parents

Select the options that are true for both asexual and sexual reproduction from the options given below:

(a) i and ii;

(b) ii and iii;

(c) ii and iv;

(d) i and iii.

2. The term ‘clone’ cannot be applied to offspring formed by sexual reproduction because:

a. Offspring do not possess exact copies of parental DNA

b. DNA of only one parent is copied and passed on to the offspring

c. Offspring are formed at different times

d. DNA of parent and offspring are completely different.

3. Asexual method of reproduction by binary fission is common to which of the following?

i. Some eukaryotes

ii. All eukaryotes

iii. Some prokaryotes

iv. All prokaryotes

Choose the correct option from the following:

(a) i and ii;

(b) ii and iii;

(c) i and iii;

(d) iii and iv.

4. A few statements with regard to sexual reproduction are given below:

i. Sexual reproduction does not always require two individuals

ii. Sexual reproduction generally involves gametic fusion

iii. Meiosis never occurs during sexual reproduction

iv. External fertilisation is a rule during sexual reproduction

Choose the correct statements from the options below:

(a) i and iv

(b) i and ii

(c) ii and iii

(d) i and iv

5. A multicellular, filamentous alga exhibits a type of sexual life cycle in which the meiotic division occurs after the formation of zygote. The adult filament of this alga has

a. haploid vegetative cells and diploid gametangia

b. diploid vegetative cells and diploid gametangia

c. diploid vegetative cells and haploid gametangia

d. haploid vegetative cells and haploid gametangia.

6. The male gametes of rice plant have 12 chromosomes in their nucleus. The chromosome number in the female gamete, zygote and the cells of the seedling will be, respectively,

a. $12,24,12$

b. $24,12,12$

c. $12,24,24$

d. $24,12,24$.

7. Given below are a few statements related to external fertilization. Choose the correct statements.

i. The male and female gametes are formed and released simultaneously

ii. Only a few gametes are released into the medium

iii. Water is the medium in a majority of organisms exhibiting external fertilization

iv. Offspring formed as a result of external fertilization have better chance of survival than those formed inside an organism

(a) iii and iv

(b) i and iii

(c) ii and iv

(d) i and iv

8. The statements given below describe certain features that are observed in the pistil of flowers.

i. Pistil may produce more than one seed

ii. Each carpel may have more than one ovule

iii. Each carpel has only one ovule

iv. Pistil have only one carpel

Choose the statements that are true from the options below:

(a) i and ii

(b) i and iii

(c) ii and iv

(d) iii and iv

9. Which of the following situations correctly describe the similarity between an angiosperm egg and a human egg?

i. Eggs of both are formed only once in a lifetime

ii. Both the angiosperm egg and human egg are stationary iii. Both the angiosperm egg and human egg are mobile

iv. Syngamy in both results in the formation of zygote Choose the correct answer from the options given below:

(a) ii and iv

(b) iv only

(c) iii and iv

(d) i and iv

10. Appearance of vegetative propagules from the nodes of plants such as sugarcane and ginger is mainly because:

a. Nodes are shorter than internodes

b. Nodes have meristematic cells

c. Nodes are located near the soil

d. Nodes have non-photosynthetic cells

11. Which of the following statements, support the view that elaborate sexual reproductive process appeared much later in the organic evolution.

i. Lower groups of organisms have simpler body design

ii. Asexual reproduction is common in lower groups

iii. Asexual reproduction is common in higher groups of organisms

iv. The high incidence of sexual reproduction in angiosperms and vertebrates

Choose the correct answer from the options given below:

(a) i, ii and iii;

(b) i, iii and iv

(c) i, ii and iv

(d) ii, iii and iv

12. Offspring formed by sexual reproduction exhibit more variation than those formed by Asexual reproduction because:

a. Sexual reproduction is a lengthy process

b. Gametes of parents have qualitatively different genetic composition

c. Genetic material comes from parents of two different species

d. Greater amount of DNA is involved in sexual reproduction.

13. Choose the correct statement from amongst the following:

a. Dioecious (hermaphrodite) organisms are seen only in animals

b. Dioecious organisms are seen only in plants

c. Dioecious organisms are seen in both plants and animals

d. Dioecious organisms are seen only in vertebrates

14. There is no natural death in single celled organisms like Amoeba and bacteria because:

a. They cannot reproduce sexually

b. They reproduce by binary fission

c. Parental body is distributed among the offspring

d. They are microscopic

15. There are various types of reproduction. The type of reproduction adopted by an organism depends on:

a. The habitat and morphology of the organism

b. Morphology of the organism

c. Morphology and physiology of the organism

d. The organism’s habitat, physiology and genetic makeup

16. Identify the incorrect statement.

a. In asexual reproduction, the offspring produced are morphologically and genetically identical to the parent

b. Zoospores are sexual reproductive structures

c. In asexual reproduction, a single parent produces offspring with or without the formation of gametes

d. Conidia are asexual structures in Penicillium

17. Which of the following is a post-fertilisation event in flowering plants?

a. Transfer of pollen grains

b. Embryo development

c. Formation of flower

d. Formation of pollen grains

18. The number of chromosomes in the shoot tip cells of a maize plant is 20 . The number of chromosomes in the microspore mother cells of the same plant shall be:

a. 20

b. 10

c. 40

d. 15

VERY SHORT ANSWER TYPE QUESTIONS

1. Mention two inherent characteristics of Amoeba and yeast that enable them to reproduce asexually.

2. Why do we refer to offspring formed by asexual method of reproduction as clones?

3. Although potato tuber is an underground part, it is considered as a stem. Give two reasons.

4. Between an annual and a perennial plant, which one has a shorter juvenile phase? Give one reason.

5. Rearrange the following events of sexual reproduction in the sequence in which they occur in a flowering plant:

embryogenesis, fertilisation, gametogenesis, pollination.

6. The probability of fruit set in a self-pollinated bisexual flower of a plant is far greater than a dioecious plant. Explain.

7. Is the presence of large number of chromosomes in an organism a hindrance to sexual reproduction? Justify your answer by giving suitable reasons.

8. Is there a relationship between the size of an organism and its life span? Give two examples in support of your answer.

9. In the figure given below the plant bears two different types of flowers marked ‘A’ and ‘B’. Identify the types of flowers and state the type of pollination that will occur in them.

10. Give reasons as to why cell division cannot be a type of reproduction in multicellular organisms.

11. In the figure given below, mark the ovule and pericarp.

12. Why do gametes produced in large numbers in organisms exhibit external fertilisation?

13. Which of the followings are monoecious and dioecious organisms.

a. Earthworm ______________________

b. Chara __________________

c. Marchantia ___________________________

d. Cockroach ___________________________

14. Match the organisms given in Column-‘A’ with the vegetative propagules given in column ‘B’.

Col. A

i. Bryophyllum

ii. Agave

iii. Potato

iv. Water hyacinth

Col. B

(a) offset

(b) eyes

(c) leaf buds

(d) bulbils

15. What do the following parts of a flower develop into after fertilisation?

a. Ovary _______________

b. Ovules ____________

SHORT ANSWER TYPE QUESTIONS

1. In haploid organisms that undergo sexual reproduction, name the stage in the life cycle when meiosis occurs. Give reasons for your answer.

2. The number of taxa exhibiting asexual reproduction is drastically reduced in higher plants (angiosperms) and higher animals (vertebrates) as compared with lower groups of plants and animals. Analyse the possible reasons for this situation.

3. Honeybees produce their young ones only by sexual reproduction. Inspite of this, in a colony of bees we find both haploid and diploid individuals. Name the haploid and diploid individuals in the colony and analyse the reasons behind their formation.

4. With which type of reproduction do we associate the reduction division? Analyse the reasons for it.

5. Is it possible to consider vegetative propagation observed in certain plants like Bryophyllum, water hyacinth, ginger etc., as a type of asexual reproduction? Give two/three reasons.

6. ‘Fertilisation is not an obligatory event for fruit production in certains plants’. Explain the statement.

7. In a developing embryo, analyse the consequences if cell divisions are not followed by cell differentiation.

8. List the changes observed in an angiosperm flower subsequent to pollination and fertilisation.

9. Suggest a possible explanation why the seeds in a pea pod are arranged in a row, whereas those in tomato are scattered in the juicy pulp.

10. Draw the sketches of a zoospore and a conidium. Mention two dissimilarities between them and atleast one feature common to both structures.

11. Justify the statement ‘Vegetative reproduction is also a type of asexual reproduction’.

LONG ANSWER TYPE QUESTIONS

1. Enumerate the differences between asexual and sexual reproduction. Describe the types of asexual reproduction exhibited by unicellular organisms.

2. Do all the gametes formed from a parent organism have the same genetic composition (identical DNA copies of the parental genome)? Analyse the situation with the background of gametogenesis and provide or give suitable explanation.

3. Although sexual reproduction is a long drawn, energy-intensive complex form of reproduction, many groups of organisms in Kingdom Animalia and Plantae prefer this mode of reproduction. Give atleast three reasons for this.

4. Differentiate between (a) oestrus and menstrual cycles; (b) ovipary and vivipary. Cite an example for each type.

5. Rose plants produce large, attractive bisexual flowers but they seldom produce fruits. On the other hand a tomato plant produces plenty of fruits though they have small flowers. Analyse the reasons for failure of fruit formation in rose.

Both these plants - rose and tomato - both selected by human beings for different characteristics, the rose for its flower and tomato for its fruit. Roses, being vegetatively propagated do not need to produce seeds.

CHAPTER 1 : REPRODUCTION IN ORGANISMS

1-c

2-a

3-c

4-b

5-d

6-c

7-b

8-a

9-b

10-b

11-c

12-b

13-c

14-c

15-d

16-b

17-b

18-a