Question

Which of the following is an incorrect statement ?

• A. Nuclear pores act as passages for proteins and RNA molecules in both directions between nucleus and cytoplasm
• B. Mature sieve tube elements possess a conspicuous nucleus and usual cytoplasmic organelles
• C. Microbodies are present both in plant and animal cells.
• D. The perinuclear space forms a barrier between the materials present inside the nucleus and that of the cytoplasm

Answer 1

The Correct Option is B

To determine the incorrect statement, let's analyze each option:

1. Nuclear pores act as passages for proteins and RNA molecules in both directions between nucleus and cytoplasm:

   This statement is correct. Nuclear pores are large protein complexes that cross the nuclear envelope, which encloses the nucleus. They regulate the movement of molecules between the nucleus and the cytoplasm, including proteins and RNA molecules. Hence, they act as passages for these molecules.

2. Mature sieve tube elements possess a conspicuous nucleus and usual cytoplasmic organelles:

   This statement is incorrect. Mature sieve tube elements, which are a key component of the phloem in plants, do not contain a nucleus or most organelles. Instead, they rely on companion cells to manage cellular functions. The absence of a nucleus is a characteristic feature that allows for efficient transport of nutrients.

3. Microbodies are present both in plant and animal cells:

   This statement is correct. Microbodies, such as peroxisomes and glyoxysomes, are small organelles that contain enzymes for metabolic processes. They are present in both plant and animal cells.

4. The perinuclear space forms a barrier between the materials present inside the nucleus and that of the cytoplasm:

   This statement is correct. The perinuclear space is the space between the inner and outer nuclear membranes, playing a role in the segregation of nuclear content from cytoplasmic content.

Thus, the incorrect statement is: Mature sieve tube elements possess a conspicuous nucleus and usual cytoplasmic organelles.