Biology

Reproduction in Organisms

Question:

What do the following parts of a flower develop into after fertilisation?
a. Ovary
b. Ovules

Answer:

a. Ovary ”Fruit
b. Ovules ”Seeds

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Reproduction in Organisms

Q 1.

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

Q 2.

Differentiate between a zoospore and a zygote.

Q 3.

Explain why meiosis and gametogenesis are always interlinked?

Q 4.

Why is reproduction essential for organisms?

Q 5.

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

Q 6.

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.

Q 7.

Match the organisms given in Column ‘A' with the vegetative propagules given in column ‘B'.
ncert-exemplar-problems-class-12-biology-reproduction-in-organisms-5

Q 8.

In the figure given below, mark the ovule and pericarp.
ncert-exemplar-problems-class-12-biology-reproduction-in-organisms-3

Q 9.

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

Q 10.

Why are offspring of oviparous animals at a greater risk as compared to offspring of viviparous animals?

Q 11.

Offspring formed due to sexual reproduction have better chances of survival. Why? Is this statement always true?

Q 12.

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

Q 13.

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

Q 14.

Describe the post-fertilization changes in a flower.

Q 15.

Which of the followings are monoecious and dioecious organisms?
a. Earthworm ——————–
b. Chara ——————–
c. Marchantia ——————-
d. Cockroach ——————

Q 16.

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

Q 17.

Define:
(a)Juvenile phase
(b)Reproductive phase
(c)Senescent phase.

Q 18.

Rearrange the following events of sexual reproduction in the sequence in which they occur in a flowering plant:  embryogenesis, fertilisation, gametogenesis, pollination.

Q 19.

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

Q 20.

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

Q 21.

Which Is a better mode of reproduction: sexual or asexual? Why?

Q 22.

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

Q 23.

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.

Q 24.

Define external fertilization. Mention its disadvantages.

Q 25.

Examine a few flowers of any cucurbit plant and try to identify the staminate and pistillate flowers. Do you know any other plant that bears unisexual flowers?

Q 26.

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.

Q 27.

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 at least three reasons for this.

Q 28.

Identify each part in a flowering plant and write whether it is haploid (n) or diploid (2n).
(a)Ovary ————————
(b)Anther ————————
(c)Egg ————————
(d)Pollen ————————
(e)Male gamete ————————
(f)Zygote ————————

Q 29.

Why is the offspring formed by asexual reproduction referred to as clone?

Q 30.

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

Q 31.

How does the progeny formed from asexual reproduction differ from those formed by sexual reproduction?

Q 32.

What do the following parts of a flower develop into after fertilisation?
a. Ovary
b. Ovules

Q 33.

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.

Q 34.

Justify the statement Vegetative reproduction is also a type of asexual reproduction'.

Q 35.

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.

Q 36.

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

Q 37.

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.
ncert-exemplar-problems-class-12-biology-reproduction-in-organisms-2

Q 38.

Higher organisms have resorted to sexual reproduction in spite of its complexity. Why?

Q 39.

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

Q 40.

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

Q 41.

What is vegetative propagation? Give two suitable examples.

Q 42.

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

Q 43.

What is % bisexual flower? Collect five bisexual flowers from your neighbourhood and with the help of your teacher find out their common and scientific names.

Q 44.

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

Q 45.

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

Q 46.

Distinguish between asexual and sexual reproduction. Why is vegetative reproduction also considered as a type of asexual reproduction?

Q 47.

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

Q 48.

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

Q 49.

Differentiate between gametogenesis from embryogenesis.

Q 50.

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