Sindh Mdcat Exclusive Course Biology Biodiversity — Solved MCQs

Question 1

What is the size of Parvovirus?

Accepted Answer

C. 20nm — Parvoviruses are non-enveloped, icosahedral particles 18 to 26 nm in diameter. Plus and minus DNA strands are packaged into separate virions in approximately equal proportion.

Question 2

Eukaryotic, multicellular, and consumers belong to _ kingdom.

Accepted Answer

D. Animalia — Kingdom Monera: It comprises unicellular, prokaryotic organisms, which can be heterotrophic or autotrophic, having no well-defined nucleus and no organelles. Kingdom Protista: Protists are eukaryotic, unicellular organisms They can be autotrophs or heterotrophs. Kingdom Fungi: Fungi can be single-celled or very complex multicellular organisms. All fungi are heterotrophic, which means that they get the energy they need to live from other organisms. They are eukaryotes. Kingdom Animalia: They are eukaryotic, multicellular, and heterotrophic.

Question 3

The numbers of capsomeres found in adenovirus capsid is?

Accepted Answer

C. 252 — The adenovirus particle consists of an icosahedral protein shell surrounding a protein core that contains the linear, double-stranded DNA genome. The shell, which is 70 to 100 nm in diameter, is made up of 252 structural capsomeres. 162 capsomeres are found in herpes virus. So, option C is correct.

Question 4

Now-a-days every newborn gets regular shots of vaccine for polio. It contains _ for polio to make a child immune against this disease.

Accepted Answer

C. Antigens — A vaccine elicits an immune response by the host so that the host is better equipped to fight against the invading organism, in any potential future instance, via the production of memory cells. It may do so by containing the antigens of the invading organism (in this case, poliovirus) so that the host’s immune system produces memory cells against the specific organism, thereby conferring active immunity against the disease. Antibiotics (option A) are not present in vaccines; they are drugs used to treat bacterial illnesses. Antibodies (option B) are not present in vaccines; they are proteins, produced by plasma cells, to ward off infection. They are produced by the immune system to fight an active infection, but they are not used in vaccines since they do not confer active immunity as the host does not produce memory cells against the invading organism. Antisera (option D) is a blood serum preparation that contains antibodies against a certain antigen or disease; they are used as a treatment for certain conditions and do not confer active immunity to the individual.

Question 5

When were bacteriophages discovered by Twort?

Accepted Answer

A. 1915 — Bacteriophages were discovered independently by Frederick W. Twort in Great Britain (1915) and Félix d'Hérelle in France (1917).

Question 6

HIV is a:

Accepted Answer

A. Virus — HIV (human immunodeficiency virus) is a virus that attacks the body's immune system. If HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome). There is currently no effective cure. Once people get HIV, they have it for life.

Question 7

Which of the following diseases is sexually transmitted?

Accepted Answer

B. AIDS — Acquired immunodeficiency syndrome (AIDS) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body's ability to fight infection and disease. You can get HIV from contact with infected blood, semen, or vaginal fluids. Most people get the virus by having unprotected sex with someone who has HIV. Another common way of getting it is by sharing drug needles with someone who is infected with HIV. Hence, Option B is correct. Tuberculosis is caused by bacteria that spread from person to person through microscopic droplets released into the air. This can happen when someone with the untreated, active form of tuberculosis coughs, speaks, sneezes, spits, laughs, or sings. Hence, Option A is incorrect. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito. Then, when the infected mosquito bites another person, the virus enters that person's bloodstream and causes an infection. Hence, Option C is incorrect. A person can get cholera by drinking water or eating food contaminated with cholera bacteria. In an epidemic, the source of the contamination is usually the feces of an infected person that contaminates water or food. Hence, Option D is incorrect.

Question 8

What type of virus is the smallpox virus?

Accepted Answer

A. DNA enveloped virus — Like other OPXVs, VARV and MPXV produce large brick-shaped particles that are approximately 140–260 nm in diameter and 220–450 nm long, containing a linear DNA genome approximately 200 kb in length. The genome, enclosed within an enveloped capsid, is monopartite and encodes around 200 genes.

Question 9

Which was the first virus to be successfully crystalized?

Accepted Answer

A. TMV — Tobacco mosaic virus was the first virus to be crystallized. It was achieved by Wendell Meredith Stanley in 1935.

Question 10

Binomial nomenclature was proposed for the first time by:

Accepted Answer

D. Carolus Linnaeus (1707) — Tyrannosaurus rex is probably the most widely known binomial. The formal introduction of this system of naming species is credited to Carl Linnaeus, effectively beginning with his work Species Plantarum in 1753.

Question 11

The shape of the tobacco mosaic virus is:

Accepted Answer

B. Rod shape — This is factual recall from the chapter of acellular life which states that TMV is a helical virus that appears rod shaped so option B is most suitable.

Question 12

Chicken pox is caused by:

Accepted Answer

B. Varicella zoster virus — Chickenpox is an infection caused by the varicella-zoster virus. It causes an itchy rash with small, fluid-filled blisters. Chickenpox is highly contagious to people who haven't had the disease or been vaccinated against it.

Question 13

The viruses are:

Accepted Answer

C. Non-cellular — Viruses are non-cellular. They only have a genome covered by a protein coat called a capsid.

Question 14

Closely related species are grouped together into _ .

Accepted Answer

E. Genus — Closely related species are grouped together into a “Genus”.

Question 15

Which of the following is the simplest form of pathogens causing diseases?

Accepted Answer

B. Prions — Infectious diseases are caused by pathogens, which include bacteria, fungi, protozoa, worms, viruses, and even infectious proteins called prions. The most simple and the smallest type of pathogens are prions.

Question 16

Mark the one Kingdom having the most conspicuous living organisms?

Accepted Answer

C. Animalia — Kingdom Animalia has the most conspicous subsets of organims because theoretically they have evolved the most and are the most advanced version of evolved species.

Question 17

Which of the following is not a viral disease?

Accepted Answer

B. Malaria — Malaria is not a viral disease and is caused by protozoa plasmodium. All other options are viral infections that include: AIDS caused by HIV virus, influenza caused by the influenza virus, chickenpox is caused by the Varicella-zoster virus(VZV) and rabies is caused by rabies lyssavirus.

Question 18

Which of the following diseases is sexually transmitted?

Accepted Answer

B. AIDS — Acquired immunodeficiency syndrome (AIDS) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body's ability to fight infection and disease. You can get HIV from contact with infected blood, semen, or vaginal fluids. Most people get the virus by having unprotected sex with someone who has HIV. Another common way of getting it is by sharing drug needles with someone who is infected with HIV. Hence, Option B is correct. Tuberculosis is caused by bacteria that spread from person to person through microscopic droplets released into the air. This can happen when someone with the untreated, active form of tuberculosis coughs, speaks, sneezes, spits, laughs, or sings. Hence, Option A is incorrect. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito. Then, when the infected mosquito bites another person, the virus enters that person's bloodstream and causes an infection. Hence, Option C is incorrect. A person can get cholera by drinking water or eating food contaminated with cholera bacteria. In an epidemic, the source of the contamination is usually the feces of an infected person that contaminates water or food. Hence, Option D is incorrect.

Question 19

Radiations are classified by its _ nature.

Accepted Answer

A. Ionizing — Radiations are mostly ionizing in nature. They are classified according to their ionizing strength.

Question 20

At which stage of HIV infection does one usually show symptoms of AIDS?

Accepted Answer

C. When HIV damages a large number of helper T-lymphocytes — AIDS is a disorder of the cell-mediated immune system of the body. The virus responsible for AIDS is HIV(Human immunodeficiency virus). There is a reduction in the number of helper T cells which stimulate antibody production by B-cells. This results in the loss of natural defense against viral infection. HIV attacks the immune system, specifically targeting the CD4 cells (T cells). HIV infection progresses through several stages by infecting Helper T cells.

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