Genetic and Epigenetic Regulation

Question 1

Uncoiling of chromatin

Answer 1

Histone Acetyltransferase adds an acetyl to histone proteins on lysine residues, histone protein tails.

Question 2

Repackaging of chromatin

Answer 2

Histone deacetylation complexes take the acetyl off the histone

Question 3

Methylation of DNA

Answer 3

Heavy methylation of the CpG island inhibits transcription
Cytosine bases in DNA are changed by enzymes, into 5-methyl cytosines

Question 4

CpG island

Answer 4

Located in the promoter region

Question 6

Dosage Compensation

Answer 6

The idea of differential regulation between the sexes in regards to the X-chromosome

Question 7

Random X-inactivation

Answer 7

Occurs at about the time of implantation, and the same X remains X-inactivated in a person as cells divide, however which X is inactivated in a person originally is random.

Question 8

Enhancer and Silencer regions

Answer 8

Can promote and inhibit gene transcription based on what proteins are bound to them.

Question 9

Alternative Splicing

Answer 9

Different proteins can be generated from the same chain of nucleotides, depend on which exons are included/excluded

Question 10

RNA Editing

Answer 10

Deamination of adenosine makes inosine, of cytosine can make uracil. Can be tissue specific, ex edited to make a stop codon.

Question 11

Small Regulatory RNA

Answer 11

Forms a hairpin, processed in cytoplasm, small fragments (miRNA) or (siRNA) are denatured and incorporated into an RNA-indicuing silencing complex (RISC). Will bind to mRNA and prevent translation.

Question 12

Positive Transcriptional regulation

Answer 12

RNA polymerase can bind to the promoter only in an activator protein binds to a site near the promoter.

Question 13

Negative transcriptional regulation

Answer 13

The native state of the DNA allows the RNA polymerase to be recruited and transcription takes palce, if repressor binds, it won’t happen.

Question 14

lacI

Answer 14

The gene for the repressor protein

Question 15

lacZ and lacY

Answer 15

Code for primary structure of proteins

Question 16

lacO

Answer 16

Operator site

Question 17

Lac Operon

Answer 17

Without lactose the repressor protein binds to the operator and prevents transcription from taking place, cells don’t usually use lactose

Question 18

When lactose levels are high….

Answer 18

cAMP levels are high, and gene is expressed at a fast rate