Bio-catalyst 3

Which of the following reactions is catalyzed by carbonic anhydrase?

• Combination of carbon dioxide and phosphoenolpyruvate

• Combination of carbon dioxide and water to form carbonic acid

• Dissociation of carbonic acid to produce hydrogen ion and hydrogen carbonate ion.

• Elimination of carbon dioxide from pyruvate

Which of the following reactions occur in erythrocytes in the pulmonary capillaries?

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Carbon dioxide in the blood is transported in the form of

I. Carbonic acid

II. Carbaminohaemoglobin

III.  Carboxyhaemoglobin

IV. bicarbonate ion

• II and IV

• III and IV

• I, II and IV

• I, III and IV

Each hemoglobin molecule can bind reversibly with

• one atom of oxygen

• one molecule of oxygen

• two molecules of oxygen

• four molecules of oxygen

Which of the following is a FALSE statement? If the action of carbonic anhydrase in red blood cells in tissue increases, one would be expected an increase in.......

• Concentration of reduced haemoglobin

• Bicarbonate ions in plasma

• Diffusion of chloride ions out of cells

• The chloride shift

Most of the carbon dioxide produced by humans is

• converted to bicarbonate ions by an enzyme in red blood cells

• bound to haemoglobin.

• transported in the erythrocytes as carbonic acid

• bicarbonate ions bound to haemoglobin

The body fluid and some blood proteins that leave the capillaries return the circulatory system via

• Active transport

• Lymphatic system

• Diffusion from the interstitial fluid into the capillaries

• Villi lining the small intestine

Which of the following structures is considered to be the pacemaker of the heart?

• Atrioventricular node

• Sinoatrial node

• Atrioventricular bundle

• Purkinje fibers

Which of the following is not a lymphoid organ?

• Tonsil

• Spleen

• Bone marrow

• Kidney

Root pressure is caused by...................

• Osmotic flow of water into xylem

• Adhesion of water molecules

• Cohesion of water molecules to xylem walls

• Transpiration of water in leaves