Which of the following is surrounded by single-membrane?

Correct option is A

The correct answer is: (a) Lysosome

A lysosome is a cellular organelle surrounded by a single membrane. It contains hydrolytic enzymes responsible for breaking down biomolecules, cellular debris, and pathogens.

Key Features of Lysosome:

1. Single-Membrane Structure:

• The lysosome is enclosed by a lipid bilayer membrane that separates its contents from the cytoplasm.

• This membrane helps maintain an acidic environment (pH ~5) essential for enzyme activity.

2. Function:

• Acts as the cell's "recycling center" by degrading and recycling cellular waste.

• Plays a role in autophagy (self-digestion) and defense mechanisms against pathogens.

3. Enzymatic Content:

• Contains hydrolytic enzymes like proteases, lipases, and nucleases that break down macromolecules.

Significance of Lysosome’s Single Membrane:

• The single membrane protects the cytoplasm from the lysosome’s degradative enzymes.

• Any disruption in the membrane can lead to uncontrolled enzyme release, causing cellular damage (e.g., in lysosomal storage diseases).

Additional Information:

• Mitochondria:

• Mitochondria have a double membrane: an outer membrane and a highly folded inner membrane (cristae).

• They are involved in ATP production through cellular respiration.

• Nucleus:

• The nucleus is also surrounded by a double membrane called the nuclear envelope, which has nuclear pores for material exchange.

• Chloroplast:

• Chloroplasts, found in plant cells, have a double membrane.

• They contain thylakoid membranes where photosynthesis takes place.