Biology - Online Test
Q1. In the human, sperm contain 22 pairs of autosomes and
Answer : Option A
Explaination / Solution:
An egg or sperm only has half of the parent's sex chromosome pair. An egg will always have an X chromosome, since the woman's sex chromosome pair only has Xs. Sperm can have either an X chromosome or a Y chromosome. If Y-chromosome containing sperm fertilize the ovum results is male.
Q2. A which one is living fossil
Answer : Option C
Explaination / Solution:
Ginkgo is a living fossil. This plant belongs to gymnosperms division. It is considered as one of the oldest plant known and still surviving in some part of wold.
Q3. Henking X-body present in 50% of sperms are now known as
Answer : Option B
Explaination / Solution:
Henking trace a specific structure in 50% of sperms. He gave the name x-body to this structure but he was not able to explain the significance of this structure. Further, investigation revealed that x-body was a chromosome, called X-chromosome.
Q4. Crop rotation is used by farmers to increase
Answer : Option A
Explaination / Solution:
Crop rotation is the method of agriculture in which leguminous plants are grown between two cereal crops. The root nodule of these bacterium fix the atmospheric nitrogen and increase the fertility of soil.
Q5. In certain parts of India, forests are burnt and the ash is mixed with the soil and the land used forcultivation leads to deforestation and this process is named as
Answer : Option D
Explaination / Solution:
Shifting cultivation is a kind of cultivation in which cultivating land is changed periodically. Forests are burnt and the ash is mixed with the soil and the land is used for cultivation of crop. This kind of cultivation causes deforestation.
Q6. Oxidative phosphorylation is
Answer : Option C
Explaination / Solution:
Oxidative phosphorylation is process in which ATP is produced by chemiosmosis in inner wall of mitochondria called cristae.
Q7. In between two walls of adjacent cells are seen
Answer : Option B
Explaination / Solution:
The middle lamella cements the tertiary walls of two adjacent plant cells. It is formed out of materials of cell plate.
Q8. How bacterial cells protect themselves from the action of their own restriction enzymes?
Answer : Option D
Explaination / Solution:
The protection is offered by the action of the methylase. The methylase recognizes the same target site as the restriction enzyme and adds a methyl group to a specific nucleotide in the restriction site. Methylated sites are not substrates for the restriction enzyme.
The bacterial DNA is methylated immediately following replication so it will not be a suitable substrate for restriction endonuclease cleavage.
Thus, the viral DNA is restricted in the bacterial cell by the restriction enzyme, and the bacterial DNA is modified by the methylase and is provided protection.
Q9. Adaptive ability is inherited because
Answer : Option D
Explaination / Solution:
An adaptive behavior is a behavior which contributes directly or indirectly to an individual's survival or reproductive success and is thus subject to the forces of natural selection.
The adaptive ability of an organism is inherited to their next generation because it has genetic basis. The adaptive traits arise due to change in gene.
Q10. Which genus has large number of closely related species
Answer : Option D
Explaination / Solution:
A genus consists of large number of closed related species. Genus Solanumconsistof larger of common species that includes, potato, tomato, Brinjalect.
