Spectrum Biology - September 2016

29.Refer to the given figure showing an antigen with

epitopes.

As ser tion Epitopes are components of antigen

that get attached with the antibody.

Rea son The combination is very much like the

lock and key analogy.

30.As ser tion IgA is the most abundant class

constituting about 10-15% of antibodies of serum.

Rea son IgA has a polypeptide called as J-chain.

31.Refer to the given figure of Datura.

As ser tion Part labelled as ‘A’ in the figure is

misused for its hallucinogenic properties.

Rea son The hallucinogens, in general produce a

dream-like state.

32.As ser tion The Insulin Dependent Diabetes

Mellitus (IDDM) is caused by the failure of α-cells.

Reason It is considered as a non-communicable

disease.

33.Refer to the given figure showing structure of an

antibody.

As ser tion The part mentioned as ‘B’ in the figure

is called Fc region.

Reason This fragment is crystallisable in cold

storage.

34.As ser tion Filariasis is caused by Wuchereria

bancrofti and Wuchereria malayi.

Reason It is transmitted from one individual to the

others by female Culex mosquitoes.

35.As ser tion Lymph nodes and spleen are primary

lymphoid organs.

Reason In primary lymphoid organs T-lymphocytes

and B-lymphocytes mature and acquire their antigen

specific receptors.

36.As ser tion MRI is very useful in the detection of

cancers of the internal organs.

Reason In MRI strong magnetic fields and

non-ionising radiations are used to detect

pathological and physiological changes in the living

tissues.

37.As ser tion Barbiturates are synthetic drugs which

are general depressants.

Reason PNS is most sensitive to barbiturates.

38.Refer to the given figure showing principal

components of human lymphatic system.

As ser tion Parts labelled as ‘A’ and ‘B’ are

primary lymphoid organs.

Reason In ‘A’ and ‘B’ respectively maturation of

B and T-lymphocytes occur.

39.As ser tion IgM is the earliest immunoglobulin to

be synthesised by the foetus.

Reason It can cross placental barrier.

B

Thoracic duct

Small intestine

Nodes

Lymphatic

vessel

A

Palatine tonsil

Right

lymphatic

duct

Lymphatic

vessel

Thoracic

duct

Cisterna

chyli

Large

intestine

Appendix

A

ANTIGEN

Binding

sites

Antigens

components

of cell wall

Antibody A

Antibody B

Epitopes

(Antigenic

determinants

of cell wall)

NH

3

NH

3

Light chain

• 
  

COO

Antigen binding site

Variable region of

the heavy chain

COO–

Hinge

Disulfide bond

Heavy chain

A

B

COO–

• 
  

COO

NH

(^3) NH
3
Variable region of
the light chain
Constant region
of heavy chain
Constant region
of light chain
Antigen
binding site