6.4

Question 1

Gene Regulation

Answer 1

The control and change to gene expression in response to different conditions in the cell or environment.

Question 2

Constitutive Genes/House-keeping Genes

Answer 2

A gene that is constantly being expressed; it does not undergo regulation of gene expression.

Question 3

At what point does regulation of gene expression occur in prokaryotes?

Answer 3

• Transcription
• Translation
• After the protein is synthesized

Question 4

Operon

Answer 4

A cluster of genes grouped together under the control of one promoter; occurs in prokaryotic genomes.

Question 5

Polycistronic

Answer 5

One continuous mRNA strand

Question 6

lac Operon

Answer 6

A cluster of genes which collectively code for the enzymes and proteins required for the cell to use lactose as a nutrient.

Question 7

Operator

Answer 7

A repressor protein that binds to a DNA sequence element; it regulates transcription

Question 8

Repressor

Answer 8

A protein that binds to a particular DNA sequence to regulate transcription; inhibits the transcription of a gene or genes

Question 9

Catabolism Activator Protein (CAP)

Answer 9

A DNA sequence to which a specific protein binds to increase the rate of transcription of a gene.

Question 10

Positive Gene Expression

Answer 10

An activator protein binds close to the promoter site making it easier for RNA polymerase to bind.

Question 11

Activator

Answer 11

A protein that binds to a particular DNA sequence to regulate transcription; it increases the rate of transcription of a gene or genes.

Question 12

Negative Gene Expression

Answer 12

Repressor protein binds to operator and prevents RNA polymerase from binding ; no transcription occurs

Question 13

trp Operon

Answer 13

A cluster of genes that govern the synthesis or the necessary enzymes required to synthesize the amino acid tryptophan
repressed when high levels of tryptophan are present

Question 14

Five Levels of Gene Regulation in Eukaryotes

Answer 14

• Pre-transcriptional
• Transcriptional
• Post-transcriptional
• Translational
• Post-translational

Question 15

Transcription Factor

Answer 15

One of a set of proteins required for initiation of transcription; it is required for the RNA polymerase complex to bind to the promoter.

Question 16

Pre-Transcriptional

Answer 16

The cell controls the extent to which DNA is exposed to transcription enzyme, thus regulating the DNA’s availability for transcription.

Question 17

Transcriptional

Answer 17

Regulates which genes are transcribed (DNA or mRNA) or controls rate at which transcription occurs.

Question 18

Post-Transcriptional

Answer 18

The mRNA molecule undergoes changes in the nucleus before translation occur. Introns are removed and exons are spliced together.

Question 19

Translational

Answer 19

• controls how often and how rapidly and mRNA transcript will be translated into proteins
• control affects the length of time it takes for mRNA to be activated and the speed at which cytoplasmic enzymes destroy mRNA

Question 20

RNA Interference

Answer 20

The regulation of gene expression by small RNA’s; it inhibits gene expression by degrading mRNA or inhibiting translation

Question 21

Post-Translational

Answer 21

• before many proteins become functional, they must pass through the cell membrane
• a number of control mechanisms affect the rate at which a protein becomes active and the time that it remains functional, including the addition of certain chemical groups