Entry Test MCQ :: Enzymes

NOTE :ANSWERS ARE PRESENT AFTER 5 MCQs

1.	Biological molecules (proteins) which catalyze a biochemical reaction and remain unchanged after completion of reaction are called
	A. Cofactor B. Coenzymes C. Activator D. Enzymes

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2.	Which statement about enzyme is incorrect:
	A. Some of them consist solely of protein with no non protein part. B. They catalyze a chemical reaction without being utilized. C. All enzymes are fibrous Proteins. D. They without their cofactor are called apoenzyme.

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3.	In which of the following location enzymes controlling cellular respiration are present?
	A. Nucleus B. Chlorophast C. Milochondria D. Ribosome

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4.	An activated enzyme consisting of polypeptide chain and a cofactor is called:
	A. Apoenzyme B. Holoenzyme C. Activated enzyme D. Both b and c

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5.	Which one forms the raw material for coenzymes?
	A. Vitamins B. Carbohydrates C. Proteins D. Metals ANSWERS OF ABOVE Five MCQs 1.(D) 2.(C) 3.(C) 4.(D) 5.(A)

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6.	A cofactor made of inorganic ion which is detachable is called
	A. Prosthetic group B. Coenzyme C. Activator D. Cofactor

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7.	Enzymes _________ the activation energy of a chemical reaction
	A. Increases B. Decreases C. Does not effect D. Increases or decreases depending upon individual enzyme

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8.	A three dimensional dcavity bearing a specific charge by which the enzyme reacts with its substrate is called
	A. Active site B. Binding site C. Catalytic site D. Allosteric site

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9.	Which step causes activation of catalytic site of an enzyme?
	A. Change in pH of the surroundings. B. Formation of Enzyme Susstrate complex. C. Change in the charge of the active site. D. Change in temperature

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10.

Lock and Key model was proposed by

A. Emil Fischer B. Koshland C. Robin Williams D. Rudolph Virchow ANSWERS OF ABOVE Five MCQs 6.(C) 7.(B) 8.(A) 9.(B) 10.(A)  11.  Which statement is incorrect about Lock and Key Model? A. Specific enzyme can transform only a specific substrate B. Active site of an enzyme is a non flexible structure. C. Active site does not change before during or even after the reaction. D. It explains the mechanism of every chemical reaction. 12.  The rate of reaction is directly proportional to the concentration of an enzyme which statement is incorrect in this respect: A. Increase in enzyme molecule increases the available active sites. B. This relation is for unlimited time period with unlimited enzyme concentration C. If the concentration is doubled the rate will become two fold. D. None of these. 13.  If the concentration of enzyme is kept constant and amount of substrate is increased a point is reached where increase in substrates concentration does not affect the reaction rate because of A. Enzymes get denatured at higher substrate conc. B. Rate of reaction is indirectly proportional to substrate concentration at this point. C. All the active sites on enzyme molecule are occupied. D. None of these. 14.  If more substrate to already occurring enzymatic reaction is added more enzyme activity is seen because: A. There is probably more substrate present than there is enzyme. B. There is probably more enzayme available than there is substrate. C. There is probably more product present than there is either substrate or enzyme. D. The enzyme substrate complex is probably failing to form during the reaction. 15.  If more substrate to already occurring enzymatic reaction is added and there is no effect on the rate of the reaction what is the form given to this situation: A. Saturation B. Denaturation C. Composition D. Inhibition ANSWERS OF ABOVE Five MCQs 11.(D) 12.(B) 13.(C) 14.(B) 15.(A)