All Free Biology MCQs with Answers

4401. A compound produced as a result of a chemical reaction of an alcohol with an acid, where a water molecule is released, is called:

• A. Acylglycerol
• B. Ester
• C. Fatty acid
• D. Wax

Explanation: Correct option: B) The compound produced as a result of a chemical reaction of an alcohol with an acid, where a water molecule is released, is called an ester.

4402. For ester formation _ is released from alcohol and _ is released from acid, which combine to form a water molecule.

• A. H, OH
• B. H, H
• C. OH, H
• D. OH, OH

Explanation: Correct option: A) During ester formation, an H (hydrogen atom) is released from the alcohol, and an OH (hydroxyl group) is released from the acid, which combine to form a water molecule.

4403. Fatty acids contain even number of carbon atoms in straight chain attached with _ atoms and having _.

• A. Hydrogen, an acidic group
• B. Oxygen, an alcohol
• C. Oxygen, an acid group
• D. Hydrogen, an alcohol

Explanation: Correct option: A) Fatty acids contain an even number of carbon atoms in a straight chain attached with hydrogen atoms and have an acidic group.

4404. The number of carbon atoms in fatty acids may be:

• A. 2-7
• B. 3-7
• C. 2-30
• D. 2-40

Explanation: Correct option: C) The number of carbon atoms in fatty acids may range from 2 to 30.

4405. In animals, the fatty acids are _ while in plants these may be _ or _.

• A. Unbranched, branched, ringed
• B. Branched, ringed, unbranched
• C. Ringed, branched, unbranched
• D. Ringed, unbranched, branched

Explanation: Correct option: A) In animals, fatty acids are unbranched, while in plants these can be unbranched, branched, or ringed.

4406. Solubility of fatty acids in organic solvents and their melting points increase with increase in the:

• A. Number of carbon atoms in chain
• B. Number of oxygen atoms in chain
• C. Number of hydrogen atoms in chain
• D. Number of acid groups in chain

Explanation: Correct option: A) The solubility of fatty acids in organic solvents and their melting points increase with an increase in the number of carbon atoms in the chain.

4407. _ is much more soluble in organic solvent than _.

• A. Acetic acid, butyric acid
• B. Butyric acid, palmitic acid
• C. Palmitic acid, butyric acid
• D. Palmitic acid, oleic acid

Explanation: Correct option: C) Palmitic acid is much more soluble in an organic solvent than butyric acid.

4408. The smallest fatty acid is:

• A. Oleic acid
• B. Palmitic acid
• C. Butyric acid
• D. Acetic acid

Explanation: Correct option: D) Acetic acid is the smallest fatty acid.

4409. Fats containing _ fatty acids are usually liquid at room temperature and are said to be oils.

• A. Saturated
• B. Straight chain
• C. Unsaturated
• D. Saturated unbranched

Explanation: Unsaturated fatty acids have double bonds and less hydrogen atoms. Causing them to have weaker intermolecular forces and lower melting points. Hence, they are liquid at room temperature.

4410. Fats containing _ fatty acids are solid at room temperature.

• A. Unsaturated
• B. Branched
• C. Saturated
• D. Ringed

Explanation: Saturated fatty acids have no carbon to carbon double bonds and so will form more bonds with hydrogen atoms and have straight chains. This will cause them to have stronger intermolecular forces and a lower melting point. Hence, they are solid at room temperature. Saturated fatty acids are animal fats.