Question

Which of these best describes the nuclear membrane:

a) It is rigid and impermeable.
b) It is identical in composition to the cell membrane.
c) It allows all molecules to pass across it into the nucleus.
d) It contains pores that allow only certain molecules to pass.

Answer 1

The nuclear membrane is a double-membrane structure that separates the nucleus from the cytoplasm. It contains nuclear pores that allow only certain molecules to pass. Hence, d) is correct.

Step-by-step explanation:

The nuclear membrane, also known as the nuclear envelope, separates the contents of the nucleus from the cytoplasm. It is a double-membrane structure composed of two lipid bilayers. The outer membrane is continuous with the rough endoplasmic reticulum, while the inner membrane contains unique lipids and proteins.

The nuclear envelope contains nuclear pores, which are responsible for regulating the movement of materials into and out of the nucleus. These pores allow only certain molecules to pass, thus making option (d) the correct description.