Biology MCQs for MDCAT/ MCAT and Test Preparation

171. The chemical which are involved as catalyst inside the living bodies are?

(a) Carbohydrates

(b) Proteins

(c) fats

(d) starch

172. Enzymes are the biological catalysts which?

(a) Allow new chemical reactions to occur

(b) Are used up during chemical reactions

(c) Alter the direction of chemical reaction

(d) After the rate of chemical reaction

173. What is TRUE about enzyme?

(a) All parts of enzyme molecule take part in reaction

(b) Enzyme lower the activation energy of reaction

(c) Any enzyme can act upon any kind of substrates

(d) They are needed in large quantities

174. What is TRUE about cofactors?

(a) Take part in reaction

(b) Increase activation energy

(c) Help enzyme in their activity

(d) Are composed of proteins

175. One of the following may function as coenzymes for the enzymes

(a) Proteins

(b) Vitamins

(c) Carbohydrates

(d) DNA

176. Increase or decrease in temperature beyond the optimum temperature:

(a) Increase the rate of reaction

(b) Not affect the rate of reaction will

(c) Decrease the rate of reaction

(d) Denature the enzyme

177. Trypsin, and enzyme work at?

(a) Alkaline pH

(b) Neutral pH

(c) Acidic pH

(d) PH does not affect its activity

178. Change the environment Tactors will affect enzymes activity and therefor may affect?

(a) Metabolism

(b) Digestion

(b) Respiration

(d) All of these

179. The body temperature at 104F is known as critical because it causes?

(a) Nerves breakdown

(b) Enzymes stop to work

(c) Boiling of body water

(d) None of these

180. Who develop the lock and key model?

(a) E.Fisher

(b) Koshland

(c) Both of these

(d) None of these