The main structural feature of protein is:

(1) The ester linkage

(2) The ether linkage

(3) The peptide linkage

(4) All of these

Keratin, a structural protein is present in:
(a) hair
(b) skin
(c) wool
(d) all of these

Blood protein is ?
(a)albumin
(b)haemoglobin
(c)both (a) and (b)
(d)none of these

A vitamin which plays a vital role in the coagulating property of blood is:-

(1) Vitamin A
(2) Vitamin D
(3) Vitamin B
(4) Vitamin K

Which is not a poison for enzymes?

(a) CN^-                       (b) Fe³⁺

(c) Pb²⁺                     (d) ${\mathrm{AsO}}_4^{3-}$

The non-proteinous substances which certain enzymes require for their activity are called:

(a) catalysts                      (b) inhibitors

(c) co-enzymes                  (d) epimers

Antibodies are ?
(a) Carbohydrates
(b) proteins
(c) phospholipids
(d) lipids

Which of the following statements about enzymes is incorrect?

(1) The catalytic action of an enzyme is not specific

(2) An enzymatic reaction is highly sensitive to temperature

(3) The catalytic action of enzymes is due to their capacity to lower the energy of activation of a particular reaction

(4) None of the above

An antigen develops antibodies which protect the body from their harmful effects. The antibodies
are:-

(a) immunoglobulins

(b) phospholipids

(c) albumins

(d) lymphocytes

Deficiency of which Vitamin develops impotencey:

(a) B

(b) C

(c) D

(d) E