Question

QUESTION 45

Which of the following is TRUE?

	A.	In induction, some genes are activated only when a particular food source is present, such as beta-galactosidase in E. coli.
	B.	Cells have to synthesize some enzymes constitutively.
	C.	Since protein synthesis requires huge amounts of energy, enzyme synthesis is carefully controlled to save energy.
	D.	In repression, certain genes are not transcribed.
	E.	All of the above are true.

49.

A.  Differentiate between the terms "aseptic technique" and "sterile". Offer examples of situations in which each is appropriate.

B.  Discuss several different physical and chemical methods of controlling microbial growth in various environments.

C. Thoroughly explain plausible consequences of failing to control microbial growth in various environments.

Answer 1

45. Answer: Option E is correct
Explanation:
All the given options are correct

Some genes are induced i.e. they get expressed only in the presence of an inducer molecule.
Ex: Lactose is an inducer for Lac operon

Some enzymes in the cell are expressed all the time as their function is essential for normal (Regular) cellular activities.
Ex: G-3-P dehydrogenase

Protein synthesis is a highly energetic process. Hence protein synthesis is tightly regulated.

When a repressor binds to an operator, the downstream structural genes are not expressed.