Biomolecules (Biology)

Three of the following statements about enzymes are correct and one is wrong. Which one is wrong?

1. Enzymes require optimum pH for maximal activity.
2. Enzymes are denatured at high temperature but in certain exceptional organisms they are effective even at temperatures 80 –90 .
3. Enzymes are highly specific.
4. Most enzymes are proteins but some are lipids.

The figure given below shows the conversion of a substrate into product by an enzyme. In which one of the four options (1 – 4) the components of reaction labelled as A, B, C and D are identified correctly? [figure]

1. array|l|l|l|l| A & B & C & D \ Potential energy & Transition state & Activation energy & Activation energy without enzyme \ array
2. array|l|l|l|l| A & B & C & D \ Transition state & Potential energy & Activation energy without enzyme & Activation energy with enzyme \ array
3. array|l|l|l|l| A & B & C & D \ Potential energy & Transition state & Activation energy with enzyme & Activation energy without enzyme \ array
4. array|l|l|l|l| A & B & C & D \ Activation energy with enzyme & Transition state & Activation energy without enzyme & Potential energy \ array

Carbohydrates are commonly found as starch in plant storage organs. Which of the following five properties of starch (A – E) make it useful as a storage material? The useful properties are

1. (A), (C) and (E)
2. (A) and (E)
3. (B) and (C)
4. (B) and (D)

A competitive inhibitor of succinic dehydrogenase is

1. -ketoglutarate
2. malate
3. malonate
4. oxaloacetate

About 98 percent of the mass of every living organism is composed of just six elements including carbon, hydrogen, nitrogen, oxygen and

1. sulphur and magnesium
2. magnesium and sodium
3. calcium and phosphorus
4. phosphorus and sulphur

An organic substance bound to an enzyme and essential for its activity is called

1. isoenzyme
2. coenzyme
3. holoenzyme
4. apoenzyme

The catalytic efficiency of two different enzymes can be compared by the

1. formation of the product
2. pH of optimum value
3. Km value
4. molecular size of the enzyme.

Which one of the following statements regarding enzyme inhibition is correct?

1. Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein.
2. Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.
3. Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate.
4. Non-competitive inhibitors often bind to the enzyme irreversibly.

Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these

1. help in regulating metabolism
2. are exclusively synthesized in the body of a living organism as at present
3. are conjugated proteins
4. enhance oxidative metabolism.

Which of the following is the simplest amino acid?

1. Alanine
2. Asparagine
3. Glycine
4. Tyrosine

Nucleotides are building blocks of nucleic acids. Each nucleotide is a composite molecule formed by

1. base-sugar-phosphate
2. base-sugar-OH
3. (base-sugar-phosphate)n
4. sugar-phosphate

Carbohydrates, the most abundant biomolecule on earth, are produced by

1. some bacteria, algae and green plant cells
2. fungi, algae and green plant cells
3. all bacteria, fungi and algae
4. viruses, fungi and bacteria.

With which one of the following enzymes is copper necessarily associated as an activator?

1. Carbonic anhydrase
2. Tryptophanase
3. Lactic dehydrogenase
4. Tyrosinase

The major role of minor elements inside living organisms is to act as

1. co-factors of enzymes
2. building blocks of important amino acids
3. constituent of hormones
4. binder of cell structure.

In which one of the following nitrogen is not a constituent ?

1. Pepsin
2. Invertase
3. Idioblast
4. Bacteriochlorophyll

Lipids are insoluble in water because lipid molecules are

1. hydrophilic
2. hydrophobic
3. neutral
4. zwitterions.

Which of the following is a reducing sugar?

1. Galactose
2. Gluconic acid
3. -methyl galactoside
4. Sucrose

Collagen is:

1. Globular protein
2. Fibrous protein
3. Carbohydrate
4. Lipid

Most abundant organic compound on earth is

1. Cellulose
2. Steroids
3. Protein
4. Lipids

Spoilage of oil can be detected by which fatty acid?

1. Linolenic acid
2. Erucic acid
3. Linoleic acid
4. Oleic acid

In plants, inulin and pectin are

1. Excretory material
2. Reserve material
3. Insect attracting material
4. Wastes

Role of enzyme in reactions is to/as

1. decrease activation energy
2. increase activation energy
3. inorganic catalyst
4. none of the above.

Which factor is responsible for inhibition of enzymatic process during feedback?

1. Substrate
2. Enzymes
3. End product
4. Temperature

ATP is

1. nucleotide
2. nucleoside
3. nucleic acid
4. vitamin.

Which of the following have carbohydrate as prosthetic group?

1. Glycoprotein
2. Chromoprotein
3. Lipoprotein
4. Nucleoprotein

Essential amino acid is

1. phenylalanine
2. glycine
3. aspartic acid
4. serine