Chapter 12 Gene Transcription and RNA Modification

Question 1

What is transcription?

Answer 1

making a copy. Synthesizing RNA from a DNA sequence

Question 2

What are structural Genes?

Answer 2

Genes that encode amino acids of polypeptides.

Question 3

What is a promoter?

Answer 3

provides site for start of transcription. Short sequence of DNA that is necessary to initiate transcription.

Question 4

What is a terminator?

Answer 4

provides site for stop of transcription

Question 5

what are coding strands?

Answer 5

non-template strands

Question 6

What are transcription factors?

Answer 6

factors that recognize base sequences and control transcription

Question 7

Regulatory sequences?

Answer 7

Regulators of transcription. Increase or decrease rate of transcription

Question 8

What is ribosome binding site?

Answer 8

short sequence on mRNA that binds and begins translation

Question 9

Codon

Answer 9

located in mRNA read in groups of three nucleotides

Question 10

What are the three stages of transcription?

Answer 10

Initiation, Elongation, Termination

Question 11

How are promoters numbered

Answer 11

in relation to transcriptional start site. (first base used as template for RNA). Numbered in negative direction with no zero

Question 12

What are subunits of core enzymes?

Answer 12

5 subunits (sixth is sigma)

Question 13

What do alpha subunits do?

Answer 13

there are two and they help properly assemble haloenzymes in process of binding DNA

Question 14

What do Beta and Beta’ do?

Answer 14

needed for binding DNA and carrying out synthesis

Question 15

What does omega do?

Answer 15

Reconginzes promoter

Question 16

what do haloenzymes do?

Answer 16

inititatie transcription

Question 17

Initiation in detail:

Answer 17

Loosley bound haloenzymes slide down DNA strand. recogniezes the promoter and -35 and -10 region. Omega has helix turn helix motif structure that binds tightly to promoter. Alpha helixace fit into grooves and form hydrogen bonds. Forming a closed complex. Double stranded DNA unwound and -10 region.

Question 18

what is p dependent termination?

Answer 18

termination requiring protein p(rho)

Question 19

What does p(rho) create?

Answer 19

Stem loops which stop transcription

Question 20

What does RNA poly 1 do in eukaryotic transcription?

Answer 20

Trancribes all genes that encode ribosomal RNA (rRNA)

Question 21

What does RNA poly 2 do in eukaryotic transcription?

Answer 21

cellular transcription because it transcribes all structural genes (sRNA)

Question 22

What does RNA Polly 3 do in eukaryotic transcritption

Answer 22

Transcribes tRNA

Question 23

What is core promter composed of?

Answer 23

Promter, tata box, trascriptional start site

Question 24

Cis Elements

Answer 24

Exert effect over super close genes

Question 25

Trans

Answer 25

Can be far from gene they control

Question 26

When is the transcription of Eukaryotic Structural genes inititated?

Answer 26

When RNA Poly II and general transcription factors bind to promoter

Question 27

What is allosteric model

Answer 27

After transcription poly II is destabalized due to release of elongation factors

Question 28

Torpedo Model

Answer 28

Endonucleus binds to 5 end and starts degrading 5 to 3

Question 29

What is colinearity?

Answer 29

one to one ration btw sequences of codons

Question 30

Exons

Answer 30

Regions within mRNA

Question 31

Introns

Answer 31

found btw exxons

Question 32

RNA splicing

Answer 32

introns removed exons connected

Question 33

Self Splicing

Answer 33

occurs btw groups 1 and 2

Question 34

Pre-mRNA

Answer 34

located in nucleus altered by splicing but needs splicosomes to occur

Question 35

Spliceosomes

Answer 35

composed of snurps which are made of RNA and protein

Question 36

What is the function of spliceosomes?

Answer 36

Find to introns hold pre-mRNA in correct config cataylze reacction that removes intron

Question 37

What is alternative splicing and is it advantageous?

Answer 37

variation in splicing do to multiple introns. And YES

Question 38

what is 5' cap and what is its function?

Answer 38

1) recognizes binding proteins required for proper exit of mRNA from nucleus 2) Cap binding recognized by initiation factors needed for first step of translatoin 3) efficient splicing of introns

Question 39

Poly A Tail

Answer 39

Important in eukaryotes string of adenine nuclteotides important for mRNA stability and synthesis of polypeptides