5-Regulation of transcription

Question 1

what do cis elements do?

Answer 1

they regulate the DNA close to them by binding gene-regulatory proteins

Question 2

what do trans elements do?

Answer 2

regulate DNA further from them as they must be expressed as a gene-regulatory protein to act

Question 3

Give the 3 Cis acting elements:

Answer 3

promoters,operators and enhancers

Question 4

What is an enhancer?

Answer 4

a nucleotide sequence that increases the rate of genetic transcription by preferentially increasing the activity of the nearest promoter on the same DNA molecule

Question 5

what is an operator?

Answer 5

a segment of DNA to which a transcription factor binds to regulate gene expression. The transcription factor is typically a repressor, which can bind to the operator to prevent transcription.

Question 6

what is a promoter? And where are they located?

Answer 6

a region of DNA that initiates transcription of a particular gene. Promoters are located near the transcription start sites of genes, on the same strand and upstream on the DNA (towards the 5’ region of the sense strand).

Question 7

What are the trans elements that encode regulatory proteins?

Answer 7

TFs,repressors and inducers (these bind to cis acting elements)

Question 8

what is a repressor?

Answer 8

blocks the attachment of RNA polymerase to the promoter, thus preventing transcription of the genes into messenger RNA. An RNA-binding repressor binds to the mRNA and prevents translation of the mRNA into protein

Question 9

what is an inducer?

Answer 9

An inducer can bind to repressors or activators. Inducers function by disabling repressors. The gene is expressed because an inducer binds to the repressor.

Question 10

what is an activator?

Answer 10

a protein (transcription factor) that increases gene transcription of a gene or set of genes. Most activators are DNA-binding proteins that bind to enhancers or promoter-proximal elements.

Question 11

do TF bind to DNA sequences named low level sequences and high-level assemblies?

Answer 11

yes

Question 12

Are transcription factors dna binding proteins?

Answer 12

yes

Question 13

what do transcription factors do?

Answer 13

involved in the process of converting, or transcribing, DNA into RNA

Question 14

what does TBF stand for and what is i?

Answer 14

TATA binding protein, it is a transcription factor (has b scaffold which is unusual for TF)

Question 15

What does AP-1 stand for and what is it?

Answer 15

Activator protein 1 (has a leucine zipper that generally binds in the major groove)

Question 16

Name 4 TFs:

Answer 16

TBF,AP-1,CAP,EGR-1

Question 17

what does the transcription factor catabolite activator protein possess (structurally)?

Answer 17

CAP has helix turn helix

Question 18

what does EGR-1 stand for?

Answer 18

Early growth response protein 1

Question 19

can prokaryotes have promoters with several response elements forming pile of transcription factors ON the promotor?

Answer 19

No but eukaryotes can

Question 20

what low level sequences do bacteria have?

Answer 20

A pribnow box

Question 21

what low level sequences do eukaryotes have? (3)

Answer 21

TATA box CAAT box and BRE

Question 22

what high level assemblies do bacteria have?

Answer 22

operator

Question 23

what high level assemblies do eukaryotes have?

Answer 23

enhancer,silencer,insulator

Question 24

what is this the definition for? a DNA sequence capable of binding transcription regulation factors, called repressors.

Answer 24

silencers

Question 25

what does this describe?a genetic boundary element that blocks the interaction between enhancers and promoters.

Answer 25

insulators

Question 26

where must an insulator reside?

Answer 26

must reside between the enhancer and promoter to inhibit their subsequent interactions. Insulators therefore determine the set of genes an enhancer can influence

Question 27

what control does the lac operon have?

Answer 27

negative and positive inducible control

Question 28

what control does the trp operon have?

Answer 28

negative respressible control

Question 29

is trancription and translation separate in prokaryotes?

Answer 29

No it is concurrent in prokaryotes