Multiple Choice Questions

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Which of the following statements about vitamin B12 is incorrect?

  • It has a cobalt atom.

  • It also occurs in plants.

  • It is also present in rain water.

  • It is needed for human body in very small amounts.


C.

It is also present in rain water.

Vitamm-B12 is chemically cyanocobalamin. It contains Co metal. All vitamins including vitamin-B12 are required in very small amounts. Neither plants nor animals are independently capable of constructing vitamin-B12. Vitamm B12 is only synthesised by bacteria as only they have enzymes necessary to synthesise vitamin B12. Vitamin-B12 is not present in rain water.


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Glucose is obtained from

  • Starch

  • Molasses

  • Both (a) and (b)

  • None of these


Enzymes are made up of

  • edible proteins

  • proteins with specific structure

  • nitrogen contaning carbohydrates

  • carbohydrates


Which of the following food-stuffs contains nitrogen?

  • Carbohydrates

  • fats

  • Proteins

  • None of these


The activation energy for a simple chemical reaction A → B is Ea in forward direction. They activation energy for reverse reaction

  • is negative of Ea

  • is always less than Ea

  • can be less than or more than Ea

  • is always double of Ea


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When a biochemical reaction is carried out in laboratory from outside of human body in the absence of enzyme than rate of reaction obtained is 10-6 times, then activation energy of reaction in the presence of enzyme is

  • 6/RT

  • P is required

  • different from Ea obtained in laboratory

  • cannot say anything


Which of the following is not present in nucleic acids?

  • Uracil

  • 2-aminopyridine

  • Thymine

  • Adenine


The deficiency of vitamin -B1 causes

  • beri-beri

  • scurvy

  • rickets

  • anaemia


Which carbohydrate is an essential constituent of plant cells?

  • Starch

  • Cellulose

  • Sucrose

  • Vitamins


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Which compound is not a lipid?

  • Lecithin

  • Lysine

  • Cerebroside

  • Cephalin


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