An enzyme pepsin highly is active in the stomach of an animal, but quickly loses
ID: 176012 • Letter: A
Question
An enzyme pepsin highly is active in the stomach of an animal, but quickly loses its activity when it leaves the stomach and arrives in the small intestines. This example most likely illustrates that enzymes are specific to the organs in which they are produced. inactivated by movement. sensitive to change in pH. inactivated by inhibitors in the small intestine. consumed by the quantities of substrate in the small intestine. An example of a pyrimindine is adenine. thymine. guanine. acridine. all are pyrimindines The induced -fit model of enzyme action was proposed by Dr Dane Fisher. involves a conformational change in the shape of the enzyme. is also called the lock-and-key model. states that substrate-enzyme interactions are rigid. proposes that very strong covalent bonds are formed upon substrate binding. Enzyme regulation may occur by several methods. Which of the following is NOT a means of enzyme regulation? Phosphorylation feedback inhibition allosteric regulation covalent modification saturation The technique that allows various proteins to be differentiated based on size, once the proteins have been denatured, is SDS PAGE. photobleaching. liposome formation. ferritin conjugated lectins. freeze fracture technique. The graph below shows a growth curve of E. coli growing in a defined medium containing equal molar amounts of glucose and lactose. Based on your knowledge of the regulation of the lac operon, the best explanation of these results is that the presence of glucose causes the formation of cAMP catabolite activator protein (CAP) complexes, which shut down the lac operon until the glucose is used up. glucose is used first. Once glucose becomes limiting, intracellular cAMP increases, forming cAMP-CAP complexes that activate the lac operon to use lactose. the bacteria are utilizing both sugars simultaneously. early on, due to the presence of lactose, the bacteria utilize the lac operon. Glucose is used later. none of the aboveExplanation / Answer
3.C.
Enzyme pepsin is highly sensitive to ph changes. It becomes inactive at higher ph which is maintained in the small intestine.
4.B
Adenine and guanine are purines.
Cytosine and Thymine are pyramidines.
5.B.
Induced fit theory proposes that when active site on the Enzyme comes in contact with the suitable substrate, the Enzyme molds itself to fit with the substrate molecule..
6.E
Saturation cannot regulate the action of an Enzyme.
7.A.
SDS PAGE Sodium dodecyl sulfate Polyacrylamide gel electrophoresis is a method used for analysis of protein based on the size.
8.B
Bacteria utilize the monosacharide glucose first as it is the simple sugar. Once glucose is depleted, bacteria starts utilizing lactose for which it needs to produce the Enzyme beta galactosidase.