Question

Three of the following statements about enzymes are correct and one is wrong. Which one is wrong.

• A. Enzymes are denatured at high temperature but in certain exceptional organisms they are effective even at ${80}^o-{90}^{o}C$
• B. Enzymes require optimum pH for maximal activity
• C. Most enzymes are proteins but some are lipids
• D. Enzymes are highly specific

Answer 1

The correct option is C Most enzymes are proteins but some are lipids

Out of the given four statements, the statement explaining the chemical nature of enzymes is wrong. The enzymes are generally complex macromolecules of globular proteins. They have a three dimensional tertiary structure. Many enzymes contain certain non-protein substances associated with them for their function. They are known as cofactors. They may be organic or inorganic compounds.

The enzymes are thermolabile. They function best at optimum temperature. The enzyme activity decreases with decrease and increase with increase in temperature and stops at 0 degrees and above 80 degrees. The enzymes of bacteria inhabiting hot springs have an optimum temperature of 70 degrees or more.

The enzymes also show maximum activity at optimum pH. Their activity slows with increase or decrease in pH.

The enzymes are specific in their action. An enzyme may catalyze only a particular kind of reaction or may even act on a particular substrate only. For example the enzyme lactase catalyses the hydrolysis of lactose and no other disaccharide.

Thus, the correct answer is option C.