Question

For effective treatment of the disease, early diagnosis and understanding its pathophysiology is very important. Which of the following molecular diagnostic technique is very useful for early detection? [NEET 2021]

(a) Western Blotting Technique

(b) Southern Blotting Technique

(c) ELISA Technique

(d) Hybridisation Technique

Answer/Explanation

Ans. (c)

ELISA stands for Enzyme Linked Immunosarbent Assay. It is a technique to detect the presence of antigens in biological samples. It is a very effective molecular diagnostic technique used for early detection. In this tectnique the antibodies in the sample binds to the specific antigen for the disease which is to be detected. There are different type of ELISA test, that includes

Direct ELISA

Indirect ELISA

Sandwich ELISA

Question

 Which of the following statements is not true for cancer cells in relation to mutations? [NEET 2016, Phase I]

(a) Mutations destroy telomerase inhibitor

(b) Mutations inactivate the cell control

(c) Mutations inhibit production of telomerase

(d) Mutations in proto-oncogenes accelerate the cell cycle

Answer/Explanation

Ans. (c)
Cancerous cells have high telomerase activity. The maintenance of telomere stability is required for the long term proliferation of tumors. This makes telomerase a target not anly for cancer diagnosis but also for the development. of novel anti-cancer therapeutic agents, e.g. telomerase inhibitors are used in cancer treatment.

Question

 Which of the following is correct regarding AIDS causative agent HIV? [NEET 2016, Phase II]

(a) HIV is enveloped virus containing one molecule of single-stranded RNA and one molecule of reverse transcriptase

(b) HIV is enveloped virus that contains two identical molecules of single-stranded RNA and two molecules of reverse transcriptase

(c) HIV is unenveloped retrovirus

(d) HIV does not escape but attacks the acquired immune response

Answer/Explanation

Ans. (b)

Statement (b) is correct. The correct form of other statements are
(a) HIV is a virus containing ssRNA and reverse transcriptase enzyme enveloped by protein coat.
(c) HIV is enveloped retrovirus.
(d) HIV escapes the immune cells and attacks helper T-cells of immune system.

Question

At which stage of HIV infection does one usually show symptoms of AIDS? [CBSE AIPMT 2014, 11]

(a) Within 15 days of sexual contact with an infected person

(b) When the infected retro virus enters host cells

(c) When HIV damages large number of helper T-lymphocytes

(d) When the viral DNA is produced by reverse transcriptase

Answer/Explanation

Ans. (c)
T-lymphocyte receptors can recognise only antigen that bound to cell membrane proteins. These lymphocytes mediate CMI (cell mediated immunity). B-lymphocytes are the major effector molecules of humoral immunity. Erythrocytes are red blood cells. Thrombocytes or platelets secrete factors, that are involved in vascular repair.

Question

 Which one of the following is not a property of cancerous cells, whereas the remaining three are? [CBSE AIPMT 2012]

(a) They compete with normal cells for vital nutrients

(b) They do not remain confined in the area of formation

(c) They divide in an uncontrolled manner

(d) They show contact inhibition

Answer/Explanation

Ans. (d)

Contact inhibition involves major histocompatibility complex and is the natural process of arresting cell growth when two or more cells come in contact with each other. It is a property of normal cells. Cancer cells divide in uncontrolled manner and do not show contact inhibition.

Question

 A certain patient is suspected to be suffering from acquired immuno deficiency syndrome. Which diagnostic technique will you recommend for its detection? [CBSE AIPMT 2011]

(a) MRI

(b) Ultra sound

(c) WIDAL

(d) ELISA

Answer/Explanation

Ans. (d)

ELISAlEnzyme Linked Immuno Sorbent. Assay), also known as an Enzyme Immuno Assay (EIA), is a biochemical technique used mainly in immunology to detect the presence of an antibody or an antigen in a sample. It is a useful tool for determining serum antibody concentrations (such as with the HIV test). The ELISA was the first screening test widely used for HIV because of its high sensitivity as it detects antibodies at very low concentrations.

Question

Which one of the following statements is correct with respect to AIDS? [CBSE AIPMT 2010]

(a) The HIV can be transmitted through eating food together with an infected person

(b) Drug addicts are least susceptible to HIV infection

(c) AIDS patients are being fully cured cent per cent with proper care and nutrition

(d) The causative HIV retrovirus enters helper T-lymphocytes thus, reducing their numbers

Answer/Explanation

Ans. (d)

In AIDS patients, the virus attacks on $\mathrm{CD}_4+\mathrm{T}$-cells(helper $\mathrm{T}$-lymphocytes responsible for the coordination of the entire immune system), infecting and killing them until none of them are left in blood. Without these crucial immune system cells, the body cannot fight against invading bacteria or viruses which leads to weaker immune system and gradually the body of the HIV positive persons become house of infections leading to multiple problems.

Question

 Carcinoma refers to [CBSE AIPMT 2003]

(a) malignant tumours of the colon

(b) benign tumours of the connective tissue

(c) malignant tumours of the connective tissue

(d) malignant tumours of the skin or mucous membrane

Answer/Explanation

Ans. (d)
Carcinoma is a malignant or metastatic tumour. It can extend to the neighbouring cells, this process is called as metastasis. These tumours are ganerally Incater in enithelial tissule and glands.
e.g. Breast cancer, skin cancer, stomach cancer, lungs cancer, pancreas cancer, etc.

Question

 Which one of the following statements is correct? [CBSE AIPMT 2009]

(a) Patients, who had undergone surgery are given cannabinoids to relieve pain

(b) Benign tumours show the property of metastasis

(c) Heroin accelerates body functions

(d) Malignant tumours may exhibit metastasis

Answer/Explanation

Ans. (d)

Malignant tumour first grows slowly. No symptoms are noticed. This stage is called the latent stage. The tumour later grows quickly. The cancer cells go beyond adjacent tissue and enter the blood and lymph. Once this happens, they migrate to many other sites in the body, where the cancer cells continue to divide. It is called as metastasis. Only malignant tumours are properly designated as cancer.

Carcinoma refers to [CBSE AIPMT 2003]

(a) malignant tumours of the colon

(b) benign tumours of the connective tissue

(c) malignant tumours of the connective tissue

(d) malignant tumours of the skin or mucous membrane

Answer/Explanation

Ans. (d)
Carcinoma is a malignant or metastatic tumour. It can extend to the neighbouring cells, this process is called as metastasis. These tumours are ganerally innated in enithelial tissue and glands.
e.g. Breast cancer, skin cancer, stomach cancer, lungs cancer, pancreas cancer, etc.

Question

 ELISA is used to detect viruses where the key reagent is [CBSE AIPMT 2003]

(a) DNA probe

(b) RNase

(c) alkaline phosphatase

(d) catalase

Answer/Explanation

Ans. (c)

The Enzyme Linked Immuno Sorbent Assay (ELISA), also known as the Enzyme Immuno Assay (EIA) has become a widely used serological technique for, detection of AIDS in the blood serum of HIV infected person. The enzymes used for labelling in ELISA include horse radish peroxidase, alkaline phosphatase, $\beta$-galactosidase, lactoperoxidase, etc.

Question

Cancerous cells can easily be destroyed by radiation due to [CBSE AIPMT 2002]

(a) rapid cell division

(b) lack of nutrition

(c) fast mutation

(d) lack of oxygen

Answer/Explanation

Ans. (a)

The ability of radiations to kill cells is highest in the tissue with highest. number of dividing cells. Tumour cells proliferate rapidly. Hence, tumours are killed more rapidly by radiations.

Question

 Reason of lung cancer is [CBSE AIPMT 2001]

(a) coal mining

(b) calcium fluoride

(c) cement factory

(d) bauxite mining

Answer/Explanation

Ans. (c)

Cancer is an uncontrolled growth and division of certain body tissues. Lung cancer is a cancer of epithelial tissue of lungs. It is mainly (95\%) caused by smoking and can be found in both male and female. It may also occur in the people working in cement factory.

Question

 Human Immunodeficiency Virus (HIV) has a protein coat and a genetic material which is [CBSE AIPMT 1998]

(a) single stranded DNA

(b) single stranded RNA

(c) double stranded RNA

(d) double stranded DNA

Answer/Explanation

Ans. (b)

AIDS (Acquired Immunodeficiency Syndrome) was first reported in USA in 1981. It is caused by HIV (Human Immunodeficiency Virus). HIV is the member of retroviruses. Later are so named because they contain an enzyme reverse transcriptase, which mediates the formation of DNA from RNA. The genetic material of HIV is single stranded RNA (ssRNA).

Question

 Hybridoma cells are [CBSE AIPMT 1999]

(a) product of spore formation in bacteria

(b) hybrid cells resulting from myeloma cells

(c) nervous cells of frog

(d) only cells having oncogenes

Answer/Explanation

Ans. (b)

A myeloma is a type of cancer associated with abnormal production of irregular antibodies. It occurs in antibody-producing cells that have lost their normal control. Clones of the hybrid cell resulting from artificial fusion of a normal antibody producing B-cell with myeloma cell are called hybridomas.

Question

Which of the following symptoms indicate radiation sickness? [CBSE AIPMT 1997]

(a) Red and ulcerated skin

(b) Nausea and anaemia

(c) Nausea and loss of hair

(d) Ulcerated skin, nausea and loss of hair

Answer/Explanation

Ans. (d)

Even lower doses of radiations cause serious damages like skin burns, nausea, loss of hairs and nails, change in blood cell count, prolonged exposure causes formation of tumours, cancer. High dose (lethal radiation exposer) may cause instant death.

Question

 Which of the following will be curable in next two decades? [CBSE AIPMT 1997]

(a) tuberculosis

(b) cancer

(c) polio myelitis

(d) None of these

Answer/Explanation

Ans. (b)

Cancer may be curable in next two decades. The completion of the human genome is causing profound changes in thinking and direction of biomedical research. Cancer is caused by malfunctioning of genes, either through activation of cancer causing oncogens (proto-oncogenes) or through inactivation of tumor suppressor genes. By comparing the active genes in the tumor to that of normal cells, the genes causing the cancer can be determined. Side by side there is a huge progress in the field of genetic engineering and biotechnology. All these aspects give us hope that cancer may be curable in next two decades.

Question

 Retroviruses are implicated as a cause for cancer in humans because they [CBSE AIPMT 1996]

(a)carry gene for reverse transcriptase

(b) may carry cellular protooncogenes in their genome

(c) may carry $v$-oncogenes in their genome

(d) carry single stranded RNA as their genetic material

Answer/Explanation

Ans. (b)

Retroviruses are implicated as a cause of cancer in humans because they may carry cellular proto-onchogenes in their genome, when these proto-oncogenes gets converted into oncogenes due to some physical, chemical or biological agents they cause cancer.

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