Light compensation zone refers to
Answer: C
The light compensation zone is the depth beyond which light does not effectively penetrate.
It is where photosynthesis exactly balances respiration, so a plant there makes no net gain. Below it no plant can survive, which is why the productive layer of a lake or sea is confined above that depth.
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Sleeping sickness in man is caused by the organism
Answer: D
Sleeping sickness in man is caused by Trypanosoma, a flagellate protozoan.
It is transmitted by the bite of the tsetse fly in tropical Africa. The parasite multiplies in the blood and lymph and eventually invades the central nervous system, causing the disordered sleep that gives the disease its name.
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Variable number of tandem repeats (VNTRs) in the DNA molecule are highly useful in
Answer: D
Variable number tandem repeats are the basis of DNA fingerprinting.
These short sequences are repeated a different number of times in each individual, so the pattern of fragment lengths is unique except in identical twins. Alec Jeffreys developed the technique in 1984.
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Lathyrism is caused by excess consumption of.......
Answer: A
Lathyrism is caused by eating too much khesari dal, Lathyrus sativus.
Its neurotoxin, BOAA, damages the motor neurons of the spinal cord and paralyses the legs irreversibly. The pulse is drought-hardy and cheap, so it is eaten most where crops have failed.
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In a bisexual flower if androcium and gynoecium mature at different time the phenomeon is known as _________
Answer: A
When the androecium and gynoecium of a bisexual flower mature at different times, the condition is dichogamy.
It prevents self-pollination and so promotes outbreeding. Where the anthers mature first it is protandry; where the stigma does, protogyny. Herkogamy achieves the same end by physical separation instead.
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Mycology is the branch of botany in which we study
Answer: B
Mycology is the study of fungi, from the Greek mykes, mushroom.
Fungi are neither plants nor animals but a kingdom of their own, with chitin cell walls and heterotrophic nutrition by absorption. Phycology covers algae and bacteriology bacteria.
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Which one of the following vitamins is known as the anti sterile factor ?
Answer: B
Tocopherol - vitamin E - is called the anti-sterility factor.
Its deficiency causes reproductive failure in laboratory animals, which is how it was discovered in 1922. It is also the body's principal fat-soluble antioxidant, protecting membrane lipids from oxidation.
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The process in which energy stored in carbohydrates is released
Answer: B
Energy stored in carbohydrate is released by respiration.
Glucose is oxidised to carbon dioxide and water and the energy captured as ATP. Photosynthesis is the reverse: it stores light energy in carbohydrate in the first place.
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Which type of Stem modification is seen in banana ?
Answer: A
The banana stem is a rhizome - a horizontal underground stem, from which the leaves and the flowering shoot arise.
What looks like the trunk is a pseudostem of tightly rolled leaf bases. The rhizome sends up suckers, which is how the plant is propagated.
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Tissue in which cells have lost the capacity of cell division
Answer: B
Cells that have lost the capacity to divide form permanent tissue.
They arise from meristematic cells that have differentiated and taken on a fixed shape and function - parenchyma, collenchyma, sclerenchyma, xylem and phloem. Only meristems retain the power of division.
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