Railway Science (Biology-Reproduction in Plant)

Total Questions: 50

11. When Mendel studied the inheritance of two traits in the pea plant, in what phenotypic ratio did he get for the plants in F2 generation? [RRC Group D 01/09/2022 (Evening)]

Correct Answer: (b) 9 : 3 : 3 : 1
Solution:

Mendel observed that the F2 progeny of his dihybrid cross had a 9 : 3 : 3 : 1 ratio and produced nine plants with round, yellow seeds, three plants with round, green seeds, three plants with wrinkled, yellow seeds and one plant with wrinkled green seeds.
Mendel carried out his key experiments using the garden pea (Pisum sativum) as a model system. Mendel’s laws of inheritance include law of dominance, law of segregation and law of independent assortment.

12. In Mendel's experiment, when F1 generation plants were self-pollinated, what was the genotypic ratio? [RRC Group D 02 /09/2022 (Morning)]

Correct Answer: (b) 1 : 2 : 1
Solution:

The possible gametes from the given genotype AABbCC are ABC and AbC. The various possibilities of their their selfing would be :
1. ABC × ABC = AABBCC
2. ABC × AbC = AABbCC
3. AbC × ABC = AABbCC
4. AbC × AbC = AAbbCC
It is evident from the above crosses that the genotypic ratio of F2 generation will be 1 : 2 : 1.

13. A true breeding tall pea plant with yellow seeds was crossed with a true breeding dwarf pea plant with green seeds. In the F1 generation, all the plants were tall. What conclusion can be drawn from this experiment? [RRC Group D 05/09/2022 (Afternoon)]

Correct Answer: (b) Tallness was dominant over dwarfness.
Solution:

Mendel purposefully crosspollinated pea plants based on their different features to make important discoveries on how traits are inherited between generations. He crossed a pure tall plant (TT) with a pure dwarf plant (tt).
In the F1 generation, tall plants are formed (Tt), when an F1 plant is subjected to self pollination, in the F2 generation, 3 tall plants (one homozygous, 2 heterozygous) and 1 dwarf plants (homozygous) are formed.

14. Identify the correct label for the following. [RRC Group D 05/09/2022 (Evening)]

Correct Answer: (a) A - stigma, B - style; C - ovary
Solution:

Stigma : It is the topmost part or receptive tip of carpels in the gynoecium of a flower. Style : It is the long tube-like slender stalk that connects the stigma and the ovary. Ovary : It is the ductless reproductive gland that holds a lot of ovules. It is the part of the plant where the seed formation takes place.

15. Which of the following types of asexual reproduction is shown by the bread mould Rhizopus? [RRC Group D 05/09/2022 (Evening)]

Correct Answer: (d) Spore formation
Solution:

Rhizopus is the species of fungus. They reproduce asexually by Spore formation. Regeneration (an asexual mode of reproduction) is common in unicellular organisms and lower multicellular organisms, such as planaria. The organism fragments when it's ready to reproduce, and new organisms are regenerated from these fragmented parts.

16. Identify the vegetative organs and reproductive organs in the following diagram of Rhizopus. [RRC Group D 06/09/2022 (Morning)]

Correct Answer: (d) a is reproductive organ while b is vegetative organ
Solution:

Rhizopus - A genus of saprophytic and parasitic fungi (under the phylum Zygomycota). Found in moist or damp areas (on organic substances like vegetables, fruits, bread, jellies, etc). Commonly known as black bread mold, pin mold, etc. Reproduction - vegetative, asexual and sexual. In the diagram, ‘a’ is sporangium, which is a reproductive organ and ‘b’ is sporangiophore, which is a vegetative organ.

17. Which of the following plants does not reproduce by vegetative propagation? [RRC Group D 06/09/2022 (Morning)]

Correct Answer: (d) Mango
Solution:

Vegetative propagation - An asexual method of plant reproduction that occurs in its leaves, roots and stem. It can occur through fragmentation and regeneration of specific vegetative parts of plants. Examples - Rhizome of ginger, the tuber of the potato, etc. The two basic propagation options for mangoes are by seed or grafting.

18. The image below shows a cross between two plants up to F2 generation. Some conclusions that can be drawn from this cross are stated below. Which option gives the INCORRECT conclusion? [RRC Group D 08/09/2022 (Morning)]

Correct Answer: (c) Both red and green are dominant though less green is produced.
Solution:

Mendel purposefully cross-Pollinated pea plants based on their different features to make important discoveries on how traits are inherited between generations. He crossed a pure tall plant (TT) with a pure dwarf plant (tt).
In the F1 generation, tall plants are formed (Tt), when an F1 plant is subjected to self pollination, in the F2 generation, 3 tall plants (one homozygous, 2 heterozygous) - Red in colour and 1 dwarf plants (homozygous) - Green in colour are formed. Only red colour is dominant and Green is recessive as the ratio of red : green is 3 : 1.

19. Which of the following is NOT a component of the male reproductive part of flower? [RRC Group D 08/09/2022 (Evening)]

Correct Answer: (d) Style
Solution:

The male reproductive parts of the flower include the anther and filament. These two structures make up the stamen which helps in the production of male gametes and is present in pollen grains. The female reproductive parts of the flower include the stigma, style, and ovary.

20. Which of the following characteristics of the pea plant was NOT used by Mendel in his experiments? [RRC Group D 09/09/2022 (Afternoon)]

Correct Answer: (a) Shape of leaves
Solution:

Mendel used Garden peas for his experiments. He selected Pisum sativum (pea plant) for his experiments because they grow quickly, are easy to breed, and have a variety of traits. He selected seven traits of the pea plant. Characters of pea plant - Flower (seed) colour, flower position, stem length, seed shape, seed colour, pod shape and pod colour.