Biology Class 9th

381. What is the affect the Increase of temperature on Enzyme Activity:

A) Decreases the Enzyme Activity

B) Increases the Enzyme Activity

C) Has No affect

D) Increases the enzyme activity but only to a point.

382. Each enzyme works at maximum rate at a certain temperature, which is called:

A) Specific Temperature

B) Maximum Temperature

C) Ideal temperature

D) Optimum temperature

383. For most enzymes the optimum temperature is :

A) 30⁰-35⁰C

B) 35⁰-40⁰C

C) 40⁰-45⁰C

D) 45⁰-50⁰C

384. When temperature rises above the optimum temperature, the rate of reaction ________.

A) Increases Rapidly

B) Increases Gradually

C) Decreases Rapidly

D) Decrease Gradually

385. Change of Structure of Enzyme is called:

A) Destructuralization

B) Alteration

C) Denaturation

D) None of the above

386. The optimum temperature for human enzymes is :

A) 33⁰C

B) 35⁰C

C) 36⁰ C

D) 37⁰ C

387. Human enzymes start to denature quickly at temperature above____

A) 35⁰C

B) 37⁰C

C) 38⁰C


388. Optimum pH for Pepsin is:

A) 2

B) 3

C) 6

D) 8

389. Trypsin works best at _______ pH.

A) 2


C) 5

D) 8

390. As the concentration of substrates increases, the rate of reaction

A) Decrease

B) Increase

C) Increases to a Limit

D) Remains constant

391. If the substrate concentration is increased beyond ________ point, the active sites of enzymes are not available for reaction.

A) Denaturation point

B) Saturation point

C) Concentration

D) none of the above

392. The Chemicals which are involved as catalysts inside living bodies are:

A) Carbohydrates

B) Fats

C) Proteins

D) Starch

393. Enzymes are biological catalysts which:

A) Allow new chemical reaction to occur

B) Are used during chemical reactions

C) Alter the direction of chemical reactions

D) Alter the rate of chemical reactions

394. What is true about enzymes?

A) All parts of enzymes molecules take part in reaction

B) Enzymes lower the activation energy of reaction

C) An enzyme can act upon many substrates

D) They are needed in large quantities

395. What is true about co-factors?

A) Take part in reaction

B) Help enzyme in activity

C) Increase activation energy

D) are composed of proteins.

396. One of the following may function as coenzyme for enzyme.

A) Protein

B) Carbohydrates

C) Vitamins


397. Increase or Decrease in temperature beyond the optimum temperature will:

A) Increase the rate of reaction

B) Decrease the rate of reaction

C) Not affect the rate of reaction

D) Denature the enzymes

398. Trypsin works at:

A) Alkaline pH

B) Acidic pH

C) Neutral Ph

D) pH does not affect it

399. Change in Environmental factors will affect enzymes activity and there ay affect:

A) Metabolism

B) Respiration

C) Digestion

D) All of them

400. Pepsin works in:

A) Acidic pH

B) Alkaline pH

C) Neutral pH

D) pH does not effect it