All Free Biology MCQs with Answers

4471. Formation of proteins is a type_.

• A. Dehydration synthesis
• B. Hydration synthesis
• C. Dehydrogenation
• D. Hydrogenation

Explanation: Dehydration synthesis, also known as condensation reaction, is a chemical process through which two molecules are covalently linked together with the removal of a water molecule. This process is the opposite of hydrolysis, where water is used to break chemical bonds. Dehydration synthesis is a common mechanism in the formation of macromolecules, including proteins, nucleic acids, and carbohydrates.

4472. Glycosidic bond is:

• A. C-O-C
• B. >C=O
• C. CONH
• D. CHO

Explanation: Carbon-oxygen association in glycosidic linkages provides stability to the complex carbohydrate molecules. Carbon combines with nitrogen in amino acid linkages to form peptide bonds and forms proteins which are very important due to their diversity in structure and functions.

4473. Vegetative source of protein:

• A. Egg
• B. Soyabean
• C. Pulses
• D. Both B and C

Explanation: The correct answer is both B and C. Soyabean and pulses are both vegetative sources of protein.

4474. Coagulated protein is:

• A. Insoluble
• B. Non folded
• C. Nonfunctional
• D. All of above

Explanation: Coagulated protein is insoluble, non-folded, and non-functional.

4475. Sterols are:

• A. Lipid
• B. Protein
• C. Carbohydrates
• D. All of these

Explanation: Sterols are a class of lipid and the most common one is cholesterol.

4476. These are properties of lipids:

• A. Insoluble in water and soluble in fat solvent.
• B. High energy content
• C. Structural component of cell membrane
• D. All of these

Explanation: Fats are insoluble in water because water is polar and fats are non polar, hence making them fat soluble only. It is present in cells in the membrane, and due to its insolubility in water helps play the structural role. Fats also provide a decent amount of energy in cells.

4477. Fatty acids containing 18-C atoms and a single double bond are?

• A. Saturated
• B. Unsaturated
• C. Oleic acid
• D. Palmitic acid

Explanation: Oleic acid is an example of a fat that has 18 carbon atoms with a single double bond, making it a monounsaturated compound. The double bond creates a bend in the chain hence the molecule is not closely packed.

4478. Which of the following is a phospholipid?

• A. Sterol
• B. Cholesterol
• C. Lecithin
• D. Steroid

Explanation: Lecithin is the only naturally occurring phospholipid, the rest are fats, therefore option C is correct.

4479. Lipids show solubility in which of the following solvents?

• A. Water
• B. Ether
• C. Inorganic solvents
• D. All solvents

Explanation: Ether is an organic solvent therefore it will be correct.

4480. Lipids have great functional significance in the human body. What are the main functions of the lipids?

• A. Energy source
• B. Structure of membrane
• C. Insulation
• D. All of these

Explanation: Fats play essential and great role in plants and animal, therefore option D is correct.