Test 2, Deck 1

Question 1

Which Eukaryotic gene regulation mechanism could increase the amount of gene produced?

Answer 1

Lenght of Poly-A Tail (increase in length)
Euchromatin (gene relaxes, more accessible)
Activators (modifies the amount of gene product)
Multiple copies
Enhancers

Question 2

Identify the type of mutation:
unmutated 3’ TAC GCG CCC ATG AGG 5’
mutated 3’ TAC GCC GCC CAT GAG 5’

Answer 2

Frameshift insertion : inserting/adding 1 nucleotide the causes a frameshift in the rest of the mRNA

Question 3

Identify the type of mutation:
unmutated 3’ TAC GCG CCC ATG AGG 5’
mutated 3’ TAC GCA CCC ATG AGG 5’

Answer 3

Silent mutation: only one change of nucleotide but same amino acid

Question 4

Identify the type of mutation:
unmutated 3’ TAC GCG CCC ATG AGG 5’
mutated 3’ TAC GCG ACC ATG AGG 5’

Answer 4

Missense mutation: only one change of nucleotide but change in amino acid

Question 5

Select all situation that would produce B-galactosidase:
A E. coli with lactose no glucose
B E.coli with lactose and glucose
C E. coli with mutant i gene with lactose and glucose
D E. coli with mutant i gene with lactose and no glucose
E E. coli with mutant i gene without lactose or glucose

Answer 5

A E. coli with lactose no glucose
D E. coli with mutant i gene with lactose and no glucose
E E. coli with mutant i gene without lactose or glucose
Gene I is the the coding gene for the repressor protein, transcription will be continuous with or without lactose but if glucose is there, lactose ignored so no transcription

Question 6

Which mutations would have the most harmful effect on the organism?
A Base pair substitution
B Deletion of 3 bases near the middle of an intron
C Single base deletion near the middle of an intron
D Single base deletion close to the end of the coding seq.
E Single base insertion near the start of the coding seq.

Answer 6

E Single base insertion near the start of the coding seq.

Because at beginning of DNA, will change the rest of the chain, changes all the amino acids in the frameshift

Question 7

Rank the worst effect on DNA to least effect on DNA
A Base pair substitution
B Deletion of 3 bases near the middle of an intron
C Single base deletion near the middle of an intron
D Single base deletion close to the end of the coding seq.
E Single base insertion near the start of the coding seq.

Answer 7

E (frameshift, changes almost all aa) - D (only changes the end of the chain, might still be readable) - A (Might change 1 aa or not) - C (changes half the aa) - B (missing one aa in the middle, no frameshift, might still be readable)

Question 8

Activators in eye lens cell are required to initiate production of the protein, crystallin. Which regulation is it?

Answer 8

Transcriptional Regulation (transcription factors) 
Activators take affect in transcription (proteins influences transcription)

Question 9

Each neuron in the Drosophilia brain has a unique version of cell recognition protein, all which are coded by the same gene. Which regulation is it?

Answer 9

Post-transcriptional regulation (alternative splicing)

1 gene = many proteins, gene product

Question 10

The inactivated X-chr in mammals is very methylated. Which Regulation is it?

Answer 10

Transcriptional regulation (DNA methylation)
added CH3 groups to cytosine in DNA can turn off the gene

Question 11

In response to light, proteins in potatoes are phosphorylated which initiates the production of green shoots. Which Regulation is it?

Answer 11

Post-translational control (modification to polypeptide, proteins are present translation is over, added phosphate groups can turn an inactive protein into an active one)

Question 12

The half-life of the mRNA for the milk protein, casein, doubles in the presence of the hormone prolactin. Which Regulation is it?

Answer 12

Post-transcriptional regulation (affects mRNA, not talking about ribosomes of tRNA)

Question 13

When the hormone testosterone binds to its receptor, the growth factor genes are activated. Which Regulation is it?

Answer 13

Transcriptional regulation (genes are activated = transcription)

Question 14

Which nucleotide of a codon (3 nu.) has the least chance of changing the amino acid linked ?

Answer 14

3rd (2nd and 1st have equal chance very high)

Question 15

Which type of Regulation could turn off a gene?

Answer 15

Chromatin remodeling (heterochromatin very condensed)
DNA methylation
RNA interference
Repressors ( transcription factors)

Question 16

An experiment is performed where bacterial cells are placed in a medium with lactose to be observed. No lactose is found in the cell Which genetic elements would mutation cause this result ?

Answer 16

Mutant Lac Y gene (permease no transport into cell)
Mutant lac promoter (binding site non-functional)
Mutant CAP (activator for RNA polymerase to attach)

Question 17

Which E. coli will produce B-galactosidase with a mutated Y lac gene, no glucose.

Answer 17

None (with/without lactose). Lac Y codes for permease which permits the transport of lactose to the cell.

Question 18

Which E. coli will produce B-galactosidase with a mutated operon promoter, no glucose.

Answer 18

None (with/without lactose). RNA polymerase won’t attach to mRNA = no translation

Question 19

Which E. coli will produce B-galactosidase with a mutated operator, no glucose.

Answer 19

With or Without lactose. The operator is where the repressor binds, if operator non-functional, can’t repress translation. It will translate continuously without the need of lactose.

Question 20

Which E. coli will produce B-galactosidase with a mutated Lac I, no glucose.

Answer 20

With or Without lactose. Lac I gene code for the repressor protein, non-functional lac I gene = no repressor = nothing stops translation. It will translate continuously without the need of lactose.