Question

Numerous Xenopus cells were exposed to varying amounts of ultraviolet light. Some of the resulting cells were observed to lack nucleoli. As a result, one would expect that the cell could not

A) perform cellular respiration.
B) replicate its DNA.
C) perform photosynthesis.
D) synthesize ribosomal RNA.
E) perform cellular respiration or replicate its DNA.

Answer 1

Cells lacking nucleoli would most likely be unable to synthesize ribosomal RNA, essential for the production of ribosomes and protein synthesis. This is due to the nucleolus' role in rRNA synthesis, and its absence halts ribosome formation.

Step-by-step explanation:

The question involves understanding cellular structures and the effects of ultraviolet (UV) light on cells. Nucleoli are responsible for the synthesis of ribosomal RNA (rRNA), a crucial component of ribosomes, which are the machinery for protein synthesis. Exposure to UV light can lead to the formation of thymine dimers in DNA, which can cause mutations and prevent normal DNA replication and repair, such as the mechanism affected in Xeroderma Pigmentosum patients. However, the nucleolus' primary function is rRNA synthesis, not DNA replication or repair directly.

Therefore, if cells lack nucleoli, a likely consequence is the impairment in the synthesis of ribosomal RNA, which would impact the production of ribosomes, and subsequently, protein synthesis.