1

### AIPMT 2002

A
edible proteins
B
proteins with specific structure
C
nitrogen containing carbohydrates
D
carbohydrates.

## Explanation

Enzymes are proteins that act as catalyst for bio-chemical processes of life. They speed up these reactions enormously and with a high degree of selectivity.
2

### AIPMT 2001

Which is the correct statement?
A
Starch is a polymer of $\alpha$-glucose.
B
Amylose is a component of cellulose.
C
Proteins are composed of only one type of amino acid.
D
In cyclic structure of fructose, there are four carbons and one oxygen atom.

## Explanation

Starch is also know as amylum which occurs in all green plants. A molecule of starch (C6H10O5)n is built of a large number of $\alpha$-glucose ring joined through oxygen-atom.
3

### AIPMT 2001

Which statement is incorrect about peptide bond?
A
C $-$ N bond length in proteins is longer than usual bond length of N $-$ C bond.
B
Spectroscopic analysis shows planar structure of group.
C
C $-$ N bond length in proteins is smaller than usual bond length of C $-$ N bond.
D
None of the above.

## Explanation

Due to resonance C — N bond in protein acquires double bond character and is smaller than usual C — N bond.
4

### AIPMT 2001

Which of the following is correct?
A
Cycloheptane is an aromatic compound.
B
Diastase is an enzyme
C
Acetophenone is an ether.
D
All of these.

## Explanation

Diastase is an enzyme. (The protein produced by living systems which acts as a biological catalyst). Enzymes are characterised by the name ending with -ase.