All Free Biology MCQs with Answers

4561. The molecular formula of oleic acid is

• A. C18H34O2
• B. C18H36O2
• C. C2H4O2
• D. C16H36O2

Explanation: This is the correct molecular formula for oleic acid, a monounsaturated fatty acid with one double bond.

4562. Liposomes are:

• A. Drug carriers
• B. Water in middle
• C. Sac of phospholipids
• D. All of the above

Explanation: Liposomes function as drug carriers, have a water-filled core, and are composed of phospholipid bilayers, making all the above statements true.

4563. Serine is a component of:

• A. Lipids
• B. Haemoglobin
• C. Phospholipids
• D. Waxes

Explanation: Serine is indeed a component of phospholipids, specifically in the form of phosphatidylserine, which plays a crucial role in cell membrane structure.

4564. In animals, fatty acids are in:

• A. Branched chain
• B. Ring
• C. Straight chain
• D. None of these

Explanation: Fatty acids in animals are usually in a straight chain configuration, meaning they have a continuous, unbranched carbon chain.

4565. The number of carbon atoms in long-chain alkanes present in waxes ranges from

• A. 2-30
• B. 4-30
• C. 25-35
• D. 25-45

Explanation: Waxes are esters of long-chain fatty acids and long-chainalcohols. The long-chain alkanes present in waxes usuallycontain 25 to 45 carbon atoms, making them very long andhydrophobic, which helps in protecting surfaces like leavesand fruits.

4566. Acylglycerols like fats and oils are esters formed by condensation reaction between:

• A. Fatty acid and water
• B. Fatty acid and glucose
• C. Fatty acid and alcohol
• D. Fatty acid and phosphates

Explanation: Esters are formed when fatty acids react with alcohols through a condensation reaction.

4567. Fats and oils have a specific gravity of about:

• A. 0.8
• B. 0.10
• C. 0.12
• D. 0.16

Explanation: Fats and oils are less dense than water, so they float on water. Their specific gravity is about 0.8, meaning they are lighter than water (specific gravity of water = 1).

4568. When two glucose (C6H12O6) molecules are combined to form a molecule of maltose (C12H22O11), the formula of maltose is not C12H24O12 because:

• A. Hydrolysis takes place
• B. Transpiration takes place
• C. Dehydration synthesis takes place
• D. Water is added

Explanation: Dehydration synthesis involves removing a water molecule to join two molecules, which is why the formula of maltose is C₁₂H₂₂O₁₁.

4569. The enantiomer of D-glucose is:

• A. D-galactose
• B. L-galactose
• C. L-glucose
• D. None of them

Explanation: Enantiomers are mirror images of each other that cannot be superimposed. The enantiomer of D-glucose is L-glucose, which has the opposite configuration at all chiral centers.

4570. Alpha 1-4 glycosidic linkage is present in:

• A. Maltose
• B. Sucrose
• C. Cellulose
• D. Cellobiose

Explanation: Maltose is a disaccharide composed of two glucose units linked by an 𝛼-1-4 glycosidic bond.