Why is sharing of injection needles between two individuals not recommended?

1

(a)

It is to prevent the spread of HIV through contaminated needles.

What is it that prevents a child to suffer from a disease he/she is vaccinated against?Give one reason.

1

(a)

1. His body develops antibodies,that circulate in the body fluids and neutralise the pathogenic agent during subsequent encounters.
2. Memory B cells and memory T cells are retained inthe system.

Which category of adaptive immunity is provided by vaccination? Why?

1

(a)

Active Immunity it is called so because the antibodies are developed by the vaccinated person's own cells in response to the antigens.

Why does an AIDS patient suffer from many other infections?

1

(a)

Due to reduction in the number helper T-cells,the immune system of the person is weak and he suffers from infections that otherwise could have been overcome.

How does tobacco smoking lead to oxygen deficiency in human body?

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(a)

Smoking leads to increases in the carbon monoxide (C0) content in the blood. which reduces the oxygen carrying capacity of haemoglobin.Hence, tobacco smoking leads to oxygen deficiency in the human body.

What would happen to immune system, if thymus gland is removed from the body of a person?

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(a)

If thymus gland is removed from the body of a person, his immune system will become weak. As a result the person's body becomes prone to infectious diseases.

Certain pathogens are tissue/organ specific.Justify the statement with suitable example.

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(a)

Certain pathogens are tissue/organ specific as they are adapted to overcome the resistance mechanisms of those tissues and organs, e.g. the pathogens that enter the gut must know a way surviving in the stomach at low p^H and must be resistant to various digestive enzymes.

Retro viruses have no DNA. However, the DNA of the infected host cell does possess viral DNA. How is it possible?

1

(a)

Retroviruses have RNA as the genetic material. After getting into the body of a person, the virus enters the macrophages. Here, RNA is replicated to form viral DNA by enzyme reverse transcriptase. The viral DNA now gets incorporated into the host cell's DNA and directs the infected cells to produce viruses.

A person is physical fit, exercises, eats balanced diet but his neighborhood was always noisy which disturbed his sleep. How can this situation affect the health of the person? Does this situation fit into the definition of health?

1

(a)

No, he is not mentally fit.
According to WHO- “health is the state of physical, mental and social well being”.

Mary Mallon, a cook along with her delicious food was also spreading Typhoid to many people. How could she do that without suffering or even knowing about it ? What was she nicknamed as? Also name the test conducted for the confirmation of the above disease.?

1

(a)

She was a carrier of typhoid.
She unknowingly was spreading typhoid through the food she prepared.
Typhoid Mary.
Widal test .

Talking of defenses of a country, we know that there are barriers which prevent the entry of foreign agents into our country. Correlate this data with the defenses of the body and name some of the barriers of our body and what term is given for such defense / immunity?

1

(a)

Barriers :- Physical (skin), Physiological (saliva), Cellular (WBC),  Cytokine  (interferons) Innate immunity (in born immunity)

On encountering a pathogen for the first time the response is generally low, but on second exposure to the same pathogen a highly intensified response is shown by the body .Give justification for this observation?

1

(a)

Body has memory of the first encounter with the pathogen .This recognises the pathogen and shows heightened immune response.

Raju was curious to experiment a new brand of cigarette. Later on he found that he was unable to quit smoking. Can this lead to addiction and what other problems can crop up?

1

(a)

Yes, increased incidence of lung cancer, coronary heart diseases, emphysema etc.

It was diagnosed by a specialist that the immune system of a patient has been suppressed. A special test was done for confirmation. Name the test as well as the disease the patient was suffering? Also give its causative agent?

1

(a)

ELISA, AIDS, HIV (Human immuno deficiency virus )

On examining a patient ,he had a mass of proliferating cells damaging the neighboring tissues also. The doctor explained the disease to the patient. Name the disease and its property?

1

(a)

Malignant tumour , Metastasis.

Cancer causing genes are called ___________.

1

(a)

Oncogenes

The chronic use of drugs & alcohol damages nervous system and liver, this is known as _________.

1

(a)

Cirrhosis

What do you mean by withdrawal syndrome?

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(a)

When the regular dose of drugs /alcohol is abruptly discontinued ,the body to manifest an unpleasant syndrome characterised by anxiety, shakiness, nausea & sweating.

What c-onc or proto-onc genes?

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(a)

Cellular onco genes or proto onco genes are present in normal cells which ,when activated under certain conditions,could lead to oncogenic transformation of the cells.

Name the scientist who discovered the life cycle of malarial parasite.

1

(a)

Sir Ronald Ross.

which type of organisms cause ringworm.

1

(a)

Fungi

A fish is used for eradication of a vector. Name the fish and the vector. 

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(a)

Gambusia fish, feed on larvae of mosquito.

All respiratory diseases do not infect the lungs. ls it true? 

1

(a)

 Yes, many diseases like common cold, bronchitis, etc, does not infect lungs, but infects other accessory organs of respiratory system.

Name the substance produced by a cell in viral infection that can protect other cells from further infection. 

1

(a)

 Interferon.

A drug is used by patients who underwent surgery. Name the drug and cause of its use. 

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(a)

Opioids or opiates like morphine, etc., are used by patients underwent surgery because it is an effective pain killer.