Question

Select the incorrect statement: (a) Micro bodies contain various enzyme and are present in both plant and animal cells. (b) Few chromosomes have non-staining secondary constriction of constant location. This give the appearance of a small fragment called the satellite. (c) Nuclei are spherical structures present in nucleoplasm and it is a site for ribosomal RNA synthesis. (d) Every chromosome essentially has a secondary constriction or the centromere on the sides of which disc shaped structures called kinetochores are present.

Short answer

The incorrect statement is (c). The statement confuses 'nuclei' and 'nucleoli'. Nucleoli, not nuclei, are the parts of the nucleus where ribosomal RNA synthesis takes place.

Step-by-step solution

Identifying statement (a)

This statement asserts that micro bodies contain various enzymes and are present in both plant and animal cells. Upon checking, it is found to be correct. Microbodies, also known as peroxisomes, are indeed present in both plant and animal cells and contain enzymes.

Identifying statement (b)

This statement says that a few chromosomes have non-staining secondary constriction of constant location that appears as a small fragment called the satellite. This statement is correct as there are indeed chromosomes known as satellite chromosomes that present this feature.

Identifying statement (c)

The statement holds that nuclei are spherical structures present in nucleoplasm and that they are the site of ribosomal RNA synthesis. This statement is incorrect because it confuses 'nuclei' and 'nucleoli'. In fact, nucleoli are the portions of the nucleus where ribosomal RNA is synthesized.

Identifying statement (d)

This statement posits that every chromosome essentially has a secondary constriction or the centromere on the sides of which disc shaped structures called kinetochores are present. This is indeed correct: every chromosome does indeed have a centromere, which serves as the point of attachment for the kinetochores.