Which of the following is the best evidence for the 'Lock-and-key model' of enzyme action?                           
1. all isolated enzymes have been identified as proteins
2. compounds similar in structure to the substrate inhibit the reaction
3. enzymes are found in living organisms and speed up certain reactions
4. enzymes determine the direction of reaction

Carbohydrates are commonly found as starch in plant storage organs. Which of the following five properties of starch (a-e) make it useful as a storage material?
(1) easily translocated
(2) chemically non-reactive
(3) easily digested by animals
(4) osmotically inactive
(5) synthesized during photosynthesis
The useful properties are :

1. (1), (2) and (5)
2. (1) and (5)
3. (2) and (3)
4. (2) and (4)

The chitinous exoskeleton of arthropods is formed by the polymerisation of–
1. D- glucosamine
2. N- acetyl glucosamine
3. Lipoglycans
4. Keratin sulphate and chondroitin sulphate

Look at the graph given below. The reaction rate, of the reaction, can be increased beyond point C by:

1. increasing the amount of substrate
2. adding more water
3. increasing the temperature
4. decreasing enzyme concentration

What level of protein organization structure explains the 3-D shape of an enzyme?

Given below is a schematic metabolic pathway. In an experiment, the concentration of enzyme 1 was increased but the concentration of enzymes 2 and 3 were kept constant. What would happen to the rate of production of D?

1. it would go down
2. it would go up
3. it would stay the same
4. it would stop

The graph shown below shows the effect of a certain factor on the rate of a reaction catalyzed by an enzyme. The X-axis would show the said factor and that will be:

In the following graph, the X-axis will show:

1. substrate concentration
2. enzyme concentration
3. pH
4. enzyme concentration or substrate concentration

The rate of enzyme action decreases at higher temperature [after a certain value] because the increased heat
1. changes the pH of the system
2. alters the active site of the enzyme
3. neutralizes the acids and bases in the system
4. increases the concentration of the enzyme

The "lock and key hypothesis", given be Emil Fischer, attempts to explain the mechanism of:
1. denaturation of enzyme proteins
2. the formation of peptide binds
3. sharing of electrons
4. enzyme specificity