Spectrum Biology - September 2016

11.As ser tion Drinking and driving is not permitted

together.

Reason By intake of alcohol vision becomes

blurred, unsteady and the field of vision is also

reduced.

12.As ser tion Ganja is the dried male inflorescence of

Cannabis sativa.

Reason It is generally smoked in cigarettes and

produces its effects almost instantaneously.

13.As ser tion Allergy involves mainly IgE antibodies and

chemicals like histamine and serotonin from the mast

cells.

Rea son The allergic tendency is passed from

parent to child.

14.As ser tion Cytotoxic T-cells (Tc) are known as

killer cells.

Rea son Cytotoxic T-cells secrete hole forming

proteins, known as perforins.

15.As ser tion Female Anopheles mosquito is

considered as the definitive host of malarial parasite.

Rea son The asexual phase of the malarial parasite

occurs in the mosquito.

16.As ser tion Entamoeba histolytica is dimorphic as it

occurs in two forms, harmful minuta form and

harmless magna form.

Rea son Entamoeba histolytica is digenetic and

lives in the stomach of humans.

17.As ser tion The stem cells of bone marrow from

which cells of immune system derived are known as

pluripotent stem cells.

Rea son The pluripotent stem cells can form either

myeloid stem cells or lymphoid stem cells.

18.As ser tion In natural passive immunity the

resistance is passively transferred from the mother

to the foetus through placenta.

Rea son IgA antibodies can cross placental barrier

to reach the foetus.

19.As ser tion Cancer is uncontrolled proliferation of

cells without any differentiation.

Reason Cancerous cells penetrate and infiltrate

into the adjoining tissues and dislocate their

functions.

20.As ser tion Cigarette smoke contains a toxic gas,

carbon monoxide that interferes with the transport

of CO 2.

Rea son Carbon monoxide produces its adverse

effects by displacing the oxygen haemoglobin

dissociation curve to the right.

21.Refer to the given figure of AIDS virus.

As ser tion HIV is a retrovirus and its infection

results in the loss of body’s natural defence against

pathogens.

Rea son HIV infects helper T-cells which

stimulate antibody production by B-cells.

22.As ser tion Toxoids are used as vaccines against

many diseases, e.g. tetanus toxoid, diphtheria

toxoid.

Rea son Toxoids are activated toxins directed at

the toxins produced by a pathogen.

23.As ser tion Sarcomas are mainly derived from

epithelial cells.

Rea son About 80% of all tumours are sarcomas.

24.As ser tion Lysozyme is a physiological barrier

that kills bacteria by dissolving their cell walls.

Rea son Lysozyme is present in tissue fluids,

sweat, urine and saliva.

25.Refer to the given figure showing mechanism of

interferon induction and action.

As ser tion Interferons act as physiological

messengers of immune cells.

Rea son Interferons provide protection against

viral infections.

26.As ser tion Effector B-cells have a longer lifespan

and they secrete hundreds of antibodies daily.

Rea son Effector cells are formed by differentiation

of some activated B-cells.

27.As ser tion Alcohol is a depressant to the brain.

Rea son In alcoholism, cerebellum is effected

followed by cerebrum.

28.As ser tion Haptens are considered as partial

antigens.

Rea son Haptens are incapable of antibody

formation by themselves, but can induce their

production by combining with carriers.

Glycoprotein spikes

Two single stranded

RNA filaments

Lipid membrane

Protein coats

Reverse transcriptase

enzyme (transcribes

DNA from RNA)

Interferon

Diffusion of

interferon

Virus

Double

stranded

RNA

Binding to

receptor

molecules

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× Antiviral

proteins

Another

unrelated

virus