Human Health and Disease — Page 9 | NEET Biology

Q81

Retroviruses are implicated as a cause for cancer in humans because they

A carry gene for reverse transcriptase

B may carry cellular proto-oncogenes in their genome

C may carry v-oncogenes in their genome

D carry single stranded RNA as their genetic material

Correct Answer

Option B

Solution

(b) Retroviruses may carry cellular proto-oncogenes; when activated to oncogenes, they trigger uncontrolled cell multiplication.

Q82

Cancerous cells can easily be destroyed by radiations due to

A rapid cell division

B lack of nutrition

C fast mutation

D lack of oxygen

Correct Answer

Option A

Solution

(a) Rapidly dividing tumour cells are most susceptible to radiation damage.

Q83

Which one of the following sets of items in the options are correctly categorized with one exception?

A UAA, UAG, UGA Stop codons - exception UAG

B Kangaroo, Koala, Wombat Australian marsupials - exception Wombat

C Plasmodium, Cuscuta, Trypanosoma Protozoan parasites - exception Cuscuta

D Typhoid, Pneumonia, Diphtheria Bacterial diseases - exception Diphtheria

Correct Answer

Option C

Solution

(c) Cuscuta is a plant parasite (dodder), not a protozoan; hence the exception in that group.

Q84

Diphtheria is caused by

A poisons released from dead bacterial cells into the host tissue

B poisons released by living bacterial cells into the host tissue

C excessive immune response by the host's body

D poisons released by virus into the host tissues

Correct Answer

Option A

Solution

(a) Diphtheria is caused by exotoxin of Corynebacterium diphtheriae which affects nerves.

Q85

Identify the correct pair: causative agent of typhoid and confirmatory test

A Plasmodium vivax - UTI test

B Streptococcus pneumoniae - Mantoux test

C Salmonella typhi / Urease test

D Salmonella typhi / Widal test

Correct Answer

Option D

Solution

(d) Salmonella typhi causes typhoid; confirmed by Widal agglutination test.

Q86

Botulism caused by Clostridium botulinum affects the

A intestine

B neuromuscular junction

C spleen

D lymph glands

Correct Answer

Option B

Solution

(b) Clostridium botulinum toxin blocks acetylcholine release at the neuromuscular junction.

Q87

For which of the following disease is there a preventive vaccine?

A AIDS

B Hepatitis B

C Syphilis

D Gonorrhea

Correct Answer

Option B

Solution

(b) Vaccine is available for Hepatitis B (serum hepatitis caused by HBV).

Q88

Bovine spongiform encephalopathy (BSE) is related to which human disease?

A Cerebral spondylitis

B Creutzfeldt-Jacob disease

C Encephalitis

D Kala-azar

Correct Answer

Option B

Solution

(b) BSE (mad cow disease) is caused by prions; the related human disease is Creutzfeldt-Jacob Disease.

Q89

Salmonella is related with

A Typhoid

B Polio

C T.B.

D Tetanus

Correct Answer

Option A

Solution

(a) Salmonella typhi causes typhoid fever with high fever and headache.

Q90

Which one of the following conditions though harmful is also a potential saviour from a mosquito-borne infectious disease?

A Leukemia

B Thalassemia

C Sickle cell anaemia

D Pernicious anaemia

Correct Answer

Option C

Solution

(c) Sickle cell anaemia provides resistance to malaria because Plasmodium cannot survive in sickled RBCs.