Question

Can I please have a lap report on Enzymes,because any one I submitted is not good. please help

Answer 1

Enzyme are the protein molecules with speed up the rate of a biological reaction without being consumed in the reaction themselves. They work by lowering the activation energy of the reaction. Activation energy is the amount of energy required to start a reaction. Enzymes do not alter the equilibrium constant of the reaction but help to achieve equilibrium early.

All the enzymes work under specific environmental condition. They are very specific for the temperature and pH at which they work. This is called as optimum temperature and optimum pH respectively. Any deviation from the optimum value, either increase or decrease, results in a decrease in the rate of enzyme activity.

The activity of enzyme is also dependent upon the substrate concentration and enzyme concentration. If enzyme concentration is kept constant, then the activity of enzyme increases with an increase in the concentration of substrate. This is because the number of substrate molecule increase and more substrate molecules can now bind to the active site of enzyme. But after a point, the rate becomes constant because of the limitation in the number of active site of enzyme. Similarly the rate of catalytic reaction increases along with the increase in enzyme concentration of substrate concentration is kept constant.

Apart from temperature and pH, the activity of enzyme is also affected by the presence of modulators. Modulators which increase the activity of enzyme are called activators and modulators which decrease the activity of enzymes are called at inhibitors.

Enzyme are very specific for the substrate molecules. The substrate molecule bind to the active site of enzyme. The active site and the substrate molecule are complementary in shape and size to each other. Even a slight change in either of them, results in the inability of substrate molecule to bind to the active site and this render the enzyme unable to convert the substrate into product. Interaction between enzyme and substrate molecule is defined by two models, lock and key hypothesis and induced fit theory.

According to lock and key hypothesis, the substrate molecule and active site of enzyme are complementary in shape and size to each other and a substrate molecules fits into the active site like a key fits into the lock.

According to induced fit theory, active site is not complementary to substrate molecule. Whenever a substrate molecule binds to the active site, active site changes its conformation and tightly fits the substrate into it.

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