Gene Expression

Question 1

The different cells types of an organism all contain the same DNA (T or F)

Answer 1

True

Question 2

6 Steps where Gene Expression can be Controlled

Answer 2

1. When/ how often a gene is transcribed
2. How an RNA transcript is spliced
3. Which mRNAs are exported from nucleus to cytosol
4. How quickly certain mRNA molecules are degraded
5. Which mRNAs are translated into proteins
6. How rapidly specific proteins are destroyed

Question 3

Which part of double helix does a transcription regulator interact/ bind with?

Answer 3

the major groove

Question 4

DNA-binding protein motifs (4)

Answer 4

1. Helix-turn-helix motif (to DNA major groove)
2. Zinc-finger
3. Beta-sheet DNA binding
4. Leucine zipper (also protein dimerization) (dimer)

Question 5

cluster of genes transcribed as a single mRNA molecule controlled by the operator

Answer 5

operon

Question 6

Tryptophan biosynthesis requires only one enzyme (T or F)

Answer 6

False, a series of enzymes is required

Question 7

Describe the process of switching the tryptophan gene on

Answer 7

Tryptophan low -> RNA polymerase binds to promotor to transcribe genes (inactive repressor)

Question 8

Describe the process of switching the tryptophan gene off

Answer 8

Tryptophan high -> Repressor protein binds to operator -> Tryptophan binds to repressor -> Blocks RNA polymerase

Question 9

Many transcriptional regulators work together to control gene expression (T or F)

Answer 9

True

Question 10

A single regulator can only control the expression of one gene (T or F)

Answer 10

False, can control many genes

Question 11

What can a combination of transcription regulators also do?

Answer 11

Induce a differentiated cell to de-differentiate