Biology MCQs with answers Page - 2

The cell membrane is primarily composed of lipids, proteins, and carbohydrates, but they are present in different proportions:

1. Lipids (Phospholipids & Cholesterol) - About 40-50%

Form the bilayer structure of the membrane.

Provide fluidity and permeability.

2. Proteins - About 50-60%

Function as transporters, receptors, enzymes, and structural components.

Can be integral (embedded) or peripheral (surface-bound).

3. Carbohydrates - About 5-10%

Found as glycoproteins or glycolipids on the outer surface.

Help in cell recognition, signaling, and immune response.

Since carbohydrates are the least abundant component of the cell membrane, option (B) is correct.

Potato is a modified stem, specifically a tuber. It develops from the underground stem of the potato plant.

Key Features of Potato as a Stem:

1. Presence of "Eyes" → These are actually nodes with axillary buds, which can sprout into new plants.
2. Stores Starch → Acts as a storage organ for nutrients.
3. Vegetative Propagation → A new plant can grow from a potato tuber.

Thus, potato is not a root, fruit, or leaf, but a modified stem (tuber).

Correct Answer: (C) Class

Explanation:

The taxonomic hierarchy (from most inclusive to least inclusive) is:

1. Kingdom (Most inclusive)
2. Phylum/Division
3. Class ← (Correct Answer, as it is the highest among the given options)
4. Order
5. Family
6. Genus
7. Species
8. Subspecies (Least inclusive)

Since Class is higher in rank than Order, Genus, and Subspecies, it is the most inclusive among the given options.

Prothrombin is a plasma protein that plays a crucial role in blood clotting.

It is produced by the liver with the help of Vitamin K.

However, when bleeding occurs, blood platelets release various clotting factors, which help convert prothrombin into thrombin, an enzyme that aids in forming a clot.

Thus, blood platelets play a significant role in activating the clotting process by releasing prothrombin and other clotting factors.

Correct Answer: (B) eyes

Explanation:

• Myopia, also known as nearsightedness, is a common vision condition where a person can see nearby objects clearly but has difficulty seeing distant objects.
• It occurs due to the elongation of the eyeball or excessive curvature of the cornea, causing light to focus in front of the retina instead of directly on it.
• Myopia is usually corrected with concave lenses or laser surgery (LASIK).