At the Breakfast Table,your Roommate Says,"Oops! I Forgot to Take

question 22

Multiple Choice

At the breakfast table,your roommate says,"Oops! I forgot to take my melatonin last night.I'd better take it now." How do you respond?

• A)"Good idea - you don't want your bones to get brittle."
• B)"Be sure not to take too much,or your blood sugar could get dangerously low."
• C)"Don't take it now - it regulates biological rhythms,and is normally high at night and low during the day."
• D)"Don't take it after a meal - it promotes the 'fight-or-flight' response,not 'rest-and-digest'."

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Definitions:

Lactose Operon

A gene regulatory mechanism in bacteria that allows the cells to adapt to the presence of lactose, enabling the digestion of this sugar when it is available.

Negative Control

A genetic control system in which a regulatory protein binds to DNA, turning off transcription of a gene. Compare with positive control.

Operon

In prokaryotes, a group of structural genes that are coordinately controlled and transcribed as a single message, plus their adjacent regulatory elements.

Protein Binding

The interaction between a protein and another molecule, which could be another protein, a small molecule, or DNA, critical for many biological processes.