The biological clock controlling circadian rhythms must ultimately ________.
A) depend on environmental cues
B) affect gene transcription
C) stabilise on a 24-hour cycle
D) speed up or slow down with increasing or decreasing temperature

Question

Quizplus · Accepted Answer

The biological clock controlling circadian rhythms is located in the suprachiasmatic nucleus (SCN) of the hypothalamus, which contains genes that regulate the production of proteins involved in circadian rhythms. This involves gene transcription, indicating that choice B is correct. The clock is able to stabilise on a 24-hour cycle due to feedback loops created by the protein products of these genes. The clock can be influenced by environmental cues such as light exposure, but ultimately it is the gene expression that controls the circadian rhythm. Temperature does not have a direct effect on the biological clock, so choice D is incorrect.

The Biological Clock Controlling Circadian Rhythms Must Ultimately ________