Free Human Health And Diseases (Daily Quiz: 9) NEET Biology Questions & Answers with Detailed Explanation & Full Review

Free Human Health And Diseases (Daily Quiz: 9) Time:

Question-1

HIV that causes AIDS, first starts destroying

(a)

(b)

(c)

(d)

Explanation:

Answer: (c)

The AIDS retrovirus, called human immunodeficiency virus (HIV), mounts a direct attack on $CD4^{+}$ T helper cells because it recognizes the CD4 coreceptors associated with these cells. HIV's attack on $CD4^{+}$ T cells cripples the immune system in at least three ways. First, HIV-infected cells die only after releasing replicated viruses that infect other $CD4^{+}$ T cells, until the entire population of $CD4^{+}$ T cell is destroyed. Second, HIV causes infected $CD4^{+}$ T cells, to secrete a soluble suppressing factor that blocks other T cells from responding to the HIV antigen. Finally, HIV may block transcription of MHC genes, hindering the recognition and destruction of infected $CD4^{+}$ T cells, and thus protecting those cells from any remaining vestiges of the immune system. The combined effect of these responses to HIV infection is to wipe out the human immune defense.


Question-2

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

(a)

(b)

(c)

(d)

Explanation:

Answer: (d)

AIDS (Acquired Immune Deficiency Syndrome) is caused by HIV retrovirus. The virus destroys the helper T-lymphocytes thus reducing their numbers.


Question-3

The sporozoites that cause infection when a female Anopheles mosquito bites a person, are found in

(a)

(b)

(c)

(d)

Explanation:

Answer: (c)

Sporozoites enter the female Anopheles mosquito when they bite an infected person where these sporozoites fertilise and multiply in the stomach wall of the female Anopheles. These then get stored in the salivary glands of the mosquito till it is again transferred to the human body by a mosquito bite.


Question-4

Reasons for alcohol abuse in adolescents are
  1. social pressure.
  2. curiosity and need for adventure, excitement and experiment.
  3. to escape from stress, depression and frustration.
  4. to overcome hardships of daily life.
Which of the statements given above are correct?

(a)

(b)

(c)

(d)


Question-5

Which one of the following in not a property of cancerous cells whereas the remaining three are

(a)

(b)

(c)

(d)


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