Nitrogenous Food is
Answer: A
Proteins are the nitrogenous foods.
They are built of amino acids, each containing an amino group, so protein is the body's source of nitrogen. Carbohydrates and lipids contain only carbon, hydrogen and oxygen.
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Which of the following statements is most accurate regarding infection with parvovirus B19?
Answer: A
The accurate statement is that parvovirus B19 causes severe anaemia because it preferentially infects erythrocyte precursors.
It uses the P antigen on red-cell precursors as its receptor and destroys them, so red cell production stops. In a healthy person the pause is harmless, but in someone with sickle cell disease or a similar condition it causes an aplastic crisis.
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How many Nucleotides make up a Codon?
Answer: A
A codon is three nucleotides.
Three bases give \( 4^3 = 64 \) combinations for twenty amino acids and a stop signal, so the code is degenerate - most amino acids have more than one codon. Two bases would give only sixteen, too few.
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What sugar is found in DNA?
Answer: B
DNA contains deoxyribose.
It differs from the ribose of RNA in lacking an oxygen at the 2′ position, which makes the molecule chemically more stable and better suited to storing information over a lifetime.
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Which of these is a carcinogen?
Answer: D
All three - cadmium, asbestos and benzene - are carcinogens.
Asbestos fibres cause mesothelioma and lung cancer, benzene causes leukaemia, and cadmium is linked with lung and prostate cancer. All are classed as Group 1 human carcinogens by the IARC.
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Bowman’s Capsule’ works as a part of the functional unit of which among the following human physiological system?
Answer: C
Bowman's capsule belongs to the excretory system.
It is the cup-shaped start of the nephron, enclosing the glomerulus. Blood is filtered under pressure across the two walls into the capsule, and the filtrate then passes down the tubule, where useful substances are reabsorbed.
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Of the following, which mechanisms are important in the death of erythrocytes (pron:eh-rith-reh-sites) in human blood? Is it
Answer: D
All three mechanisms destroy red cells.
Most are engulfed by macrophages in the spleen and liver - phagocytosis. Some rupture in the circulation, which is haemolysis, and some are damaged mechanically forcing through narrow capillaries. A red cell lives about 120 days.
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Surplus red blood cells, needed to meet an emergency, are MAINLY stored in which organ of the human body?
Answer: B
Surplus red cells are stored mainly in the spleen.
It holds a reserve that contraction of its smooth muscle can release into the circulation during haemorrhage or strenuous exercise. The spleen also filters out worn-out red cells, which is why it is called the graveyard of erythrocytes.
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When a human donor gives a pint of blood, how many weeks are required for the body RESERVE of red corpuscles to be replaced?
Answer: C
About 7 weeks are needed to replace the body's reserve of red corpuscles after giving a pint of blood.
The plasma volume is restored within a day or two, and the red cell count within a few weeks, but the iron stores that back it up take considerably longer - which is why donors are asked to wait about three months.
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The condition in which there is a DECREASE in the number of white blood cells in humans is called
Answer: B
A fall in the number of white cells is leukopenia.
A rise is leukocytosis, and a malignant proliferation of immature white cells is leukaemia. Leukopenia leaves the patient vulnerable to infection and follows chemotherapy, radiation and some viral illnesses.
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