Human Health and Disease — Page 6 | NEET Biology

Q51

Hypersensitivity to an allergen is associated with

A aberrant functioning of the immune mechanism

B increase in ambient temperature

C age of the individual

D food habits

Correct Answer

Option A

Solution

(a) Allergy reactions occur due to hypersensitivity — aberrant immune functioning releasing histamine.

Q52

Which one of the following statements is correct with respect to immunity?

A Preformed antibodies need to be injected to treat the bite by a viper snake.

B The antibodies against small pox pathogen are produced by T-lymphocytes.

C Antibodies are protein molecules each of which has four light chains.

D Rejection of a kidney graft is the function of B-lymphocytes.

Correct Answer

Option A

Solution

(a) Viper snake bite treatment requires injection of preformed antibodies (passive immunization).

Q53

The letter T in T-lymphocyte refers to

A Thalamus

B Tonsil

C Thymus

D Thyroid

Correct Answer

Option C

Solution

(c) T-lymphocytes differentiate in the thymus gland.

Q54

A person likely to develop tetanus is immunised by administering

A preformed antibodies

B wide spectrum antibiotics

C weakened pathogens

D non-viable germs

Correct Answer

Option C

Solution

(c) Tetanus toxoid (inactivated toxin) is administered to develop active immunity against tetanus.

Q55

Select the correct statement with respect to diseases and immunisation?

A If due to some reason B- and T-lymphocytes are damaged, the body will not produce antibodies against a pathogen

B Injection of dead/inactivated pathogens causes passive immunity

C Certain protozoans have been used to mass produce hepatitis B vaccine.

D Injection of snake antivenom against snake bite is an example of active immunisation

Correct Answer

Option A

Solution

(a) B and T-lymphocytes produce antibodies; if damaged, body cannot produce antibodies against pathogens.

Q56

Which one of the following acts as a physiological barrier to the entry of microorganisms in human body?

A Epithelium of urogenital tract

B Tears

C Monocytes

D Skin

Correct Answer

Option D

Solution

(d) Skin acts as a physical/physiological barrier preventing entry of microorganisms.

Q57

The cell-mediated immunity inside the human body is carried out by:

A B-lymphocytes

B Thrombocytes

C Erythrocytes

D T-lymphocytes

Correct Answer

Option D

Solution

(d) T-lymphocytes mediate cell-mediated immunity (CMI), responsible for graft rejection.

Q58

Which of the following statements is not true for retroviruses?

A DNA is not present at any stage in the life cycle of retroviruses

B Retroviruses carry gene for RNA-dependent DNA polymerase

C The genetic material in mature retroviruses is RNA

D Retroviruses are causative agents for certain kinds of cancer in man

Correct Answer

Option A

Solution

(a) Retroviruses make DNA from RNA via reverse transcriptase, so DNA is present at some stage.

Q59

AIDS is caused by HIV that principally infects:

A all lymphocytes

B activator B cells

C cytotoxic T cells

D T4 lymphocytes

Correct Answer

Option D

Solution

(d) AIDS virus infects T4 (helper) lymphocytes.

Q60

Which one of the following statements is correct?

A Benign tumours show the property of metastasis.

B Heroin accelerates body functions.

C Malignant tumours may exhibit metastasis.

D Patients who have undergone surgery are given cannabinoids to relieve pain.

Correct Answer

Option C

Solution

(c) Malignant tumours may exhibit metastasis — spread to other locations via lymph or blood.