CBSE Class 12 Biology Reproduction In Organisms Question Bank

MULTIPLE CHOICE QUESTIONS

Question. Based on cellular mechanisms there are two major types of regeneration found in the animals.Which one of the following is the correct example of the type mentioned?
(a) Morphallaxis - Regeneration of two transversely cut equal pieces of a Hydra into two small Hydras.
(b) Epimorphosis - Replacement of old and dead erythrocytes by the new ones.
(c) Morphallaxis - Healing up of a wound in the skin.
(d) Epimorphosis - Regeneration of crushed and filtered out pieces of a Planaria into as many new Planarians.
Answer. A

Question. Which form of reproduction is correctly matched?
(a) Euglena → transverse binary fission
(b) Paramecium → longitudinal binary fission
(c) Amoeba → multiple fission
(d) Plasmodium → binary fission
Answer. C

Question. Which reproductive adaptation is characteristic of most terrestrial vertebrates but not of most aquatic vertebrates? [2009]
(a) External fertilization
(b) Internal fertilization
(c) Motile gametes
(d) External development
Answer. B

Question. Identify the events (A, B, D and E) in life of general reproduction-

(a) A-Gamete transfer, B-Gametogeneis,D-Zygote formation, E-Embryogenesis
(b) A-Gametogeneis, B-Gamete transfer,D-Zygote formation, E-Embryogenesis
(c) A-Gametogeneis, B-Zygote formation,D-Gamete transfer, E-Embryogenesis
(d) A-Gametogeneis, B-Gamete transfer,D-Embryogenesis, E-Zygote formation.
Answer. B

Question. Which of the following statements is incorrect ?
(i) Bamboo species flower only once in their life time, generally after 50-100 years and produce large number of fruits and die.
(ii) In animals, the juvenile phase is followed by morphological and physiological changes prior to active reproductive behaviour.
(iii) The reproductive phase is of same duration in all organisms.
(iv) Juvenile phase is the period of growth between the birth of an individual till it reaches reproductive maturity.
(a) Only (i)
(b) Only (ii)
(c) Only (iii)
(d) Only (iv)
Answer. C

Question. In a practical test, a student has to identify the organisms in which syngamy does not occur. In those organisms the female gamete undergoes development to form new organisms without fertilization. This phenomenon is called "X".Identify the organisms and the phenomenon "X". 
(a) Frog, Parthenogenesis
(b) Lizards, Gametogenesis
(c) Rotifers, Embryogenesis
(d) Honeybee, Parthenogenesis
Answer. D

ASSERTION REASON QUESTIONS

Directions : Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.
(a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.

Question. Assertion : Leaves of Bryophyllum, Begonia help in vegetative multiplication.
Reason : Leaves of these plants possess adventitious buds.
Answer. A

Question. Name the vegetative propagules in the following:
(a) Agave (b) Bryophyllum
Answer. (a) In Agave, bulbils are the vegetative propagules.
(b) In Bryophyllum, vegetative propagation is carried out by adventitious buds that arise from notches present at margins of leaves.

Question. Give one example each of the plant that reproduces by
(a) runner (b) offset 
Answer. (a) Lawn grass reproduces by runner.
(b) Eichhornia reproduces by offset.

Question. Give one example each of the fungus which reproduces by :
(a) budding (b) conidia
Answer. (a) Yeast reproduces asexually by budding.
(b) Penicillium reproduces asexually by conidia formation.

Question. Name an alga that reproduces asexually through zoospores. Why are these reproductive units so called? 
Answer. Chlamydomonas (an algae) reproduces asexually through zoospore formation. These spores are unicellular, naked (without cell wall), motile and flagellated and hence named zoospores.

Question. Name an organism where cell division in itself is a mode of reproduction.
Answer. In Amoeba asexual reproduction takes place by division of parent body.

Question. Which one of the following statements is true of yeast?
(i) The cell divides by binary fission. One of them develops into a bud.
(ii) The cell divides unequally. The smaller cell develops into a bud.
(iii) The cell produces conidia which develop into a bud.
Answer. (ii) Yeast reproduce by budding. The cell divides unequally. The smaller cells develop into a bud.

Question. Which of the following statements is true of Hydra?
(i) It produces asexual gemmules.
(ii) It produces unicellular bud.
(iii) It produces multicellular bud.
Answer. (iii) Hydra produces multicellular bud.

Question. Which one of the following statements is true of ginger?
(i) Germinating bud appears from the eye of the stem tuber.
(ii) Germinating bud appears from the node of rhizome.
(iii) Germinating bud appears from the notch of the leaf margin. 
Answer. (ii) Germinating bud appears from the node of rhizome of ginger.

Question. Which ones of the following organisms exhibit binary fission?
Bacillus, Penicillium, Yeast, Amoeba
Answer. Bacillus and Amoeba reproduce by binary fission. In this process, the parent organism divides into two equal halves each forming an independent daughter organism.

Question. How does Penicillium reproduce asexually?
Answer. Penicillium reproduces asexually by conidia formation. These are non-motile spores produced singly or in chains by constriction at the tip or lateral side of special hyphal branches called conidiophores.These are produced exogenously, dispersed by wind and germinate directly by giving out germ tubes.

Question. Offspring derived by asexual reproduction are called clones. Justify giving two reasons.
Answer. In asexual reproduction, offspring are produced by a single parent with or without the involvement of gamete. THe offspring are produced are similar to one another and, are also exact copies of their parents. Thus, these offspring are morphologically and genetically similar and hence called as clone.

Question. Cut-pieces of a Bryophyllum leaf when put into wet soil produce new plants. How?
Answer. Cut pieces of Bryophyllum leaf when put in wet soil produce new plant due to presence of adventitious buds. Buds present on the marginal notches of leaves of Bryophyllum help in vegetative propagation.

Question. Unicellular organisms are immortal, whereas multicellular organisms are not. Justify.
Answer. Most unicellular organisms specially those which undergoes binary fission are immortal
because they reproduce by cell division. The parent body as a whole constitutes the reproductive unit and disappears when its division into daughter individuals is completed. There is no remains of parent body cell and thus, parent cannot be said to have died. Infact, after binary fission, the parent continues living as two daughter individuals. In multicellular organisms reproduction occurs in specialised organs involving specialised cells. The whole body of parent dies due to ageing and senescence.

Question. (a) Name the organisms that reproduce through the following reproductive structures.
(i) Conidia (ii) Zoospores
(b) Mention similarity and one difference between these two reproductive units.
Answer. (a) (i) Penicillium reproduces through conidia formation.
(ii) Chlamydomonas reproduces through zoospores formation.
(b) Similarity - Conidia and zoospores, both are asexual reproductive structures.
Difference : Conidia are non-motile spores whereas zoospores are motile and flagellated spores.

Question. Meiosis is an essential event in the sexual life cycle of any organism. Give two reasons.
Answer. Meiosis is an essential event in the life cycle of a sexually reproducing organism because:-
(i) It helps to restore diploid chromosome number during fertilisation.
(ii) It is a source of variation. Random segregation of chromosomes and exchange of genetic material between homologous chromosomes increases the genetic diversity.

Question. Write the two pre-fertilisation events from the list given below:
Syngamy, Gametogenesis, Embryogenesis, Pollination 
Answer. Two pre-fertilisation events are gametogenesis and pollination.

Question. Give one example of an animal which exhibits oestrous cycle. 
Answer. Cows exhibits oestrous cycle.

Question. Which of the following statements is true of date-plam?
(i) It is monoecious producing both staminate flowers and pistillate flowers in the same plant.
(ii) It is monoecious producing staminate flowers in one tree and pistillate flowers in another tree.
(iii) It is dioecious producing staminate flowers in one tree and pistillate flowers in another tree.
Answer. (iii) Date palm is a dioecious plant producing staminate flower in one tree and pistillate flower in another tree.

Please click on below link to download CBSE Class 12 Biology Reproduction In Organisms Question Bank