Transcription

Question 1

DNA–>mRNA–>Polypeptide

(transcribed) (translated)

Answer 1

Central Dogma of Molecular Biology

Question 2

Label nucleotides with (-) numbers

Answer 2

Upstream of the +1 site

Question 3

Label nucleotides with (+) numbers

Answer 3

Downstream of the +1 site

Question 4

Place where transcription starts

-NOT the start codon

Answer 4

+1 site

Question 5

Where transcription stops

-NOT stop codon

Answer 5

Stop

Question 6

Molecules involved in transcription

Answer 6

mRNA
DNA
transcription factors
RNA polymerase
nTPs (ATP, CTP, GTP, UTP)

Question 7

Strand involved with transcription

Answer 7

DNA template strand

Question 8

Strand not involved with transcription

Answer 8

DNA coding strand

Question 9

1. DNA is locally ______.

Answer 9

denatured

Question 10

2. ______assembles NTPs completemtary to the template strand

Answer 10

RNA polymerase

Question 11

• Reads the template 3’ to 5’
• no primer needed
• synthesizes 5’ to 3’

Answer 11

RNA polymerase

Question 12

3. RNA/DNA duplex ________ when bigger than ______ base pairs.

Answer 12

dissociates; 20.

Question 13

4. ____________ template reannealed behind bubble.

Answer 13

Coding

Question 14

RNA transcript is the same as _______ strand except it has uracil instead of thymine

Answer 14

coding

Question 15

Major steps in transcription

Answer 15

1. Initiation
2. Elongation
3. Termination

Question 16

Sequence with a specific function

Answer 16

consensus sequence

Question 17

• It is a bacterial transcription initiation factor that enables specific binding of RNA polymerase to gene promoters.
• Positions polymerase in the correct location

Answer 17

sigma subunit of bacterial RNA polymerase

Question 18

Step 1: Initiation in E. coli

Answer 18

1. Sigma binds to 2 consensus sequences -10 box and -35 box.
   - this orients polymerase at the +1 site.
2. RNA polymerase synthesizes RNA
   - no primer is needed

Question 19

The sigma subunit of bacterial RNA pol. ______.

a. binds to a bacterial gene’s promoter
b. is composed of both polypeptide and RNA molecules
c. is required for RNA polymerization
d. is required for termination of transcription
e. is required for ribosomal binding

Answer 19

a. binds to a bacterial gene’s promoter

Question 20

“new strand”

Answer 20

nascent strand

Question 21

______ in mRNA causes RNA to stop transcribing.

Answer 21

Hairpin

Question 22

Step that occurs when RNA/DNA duplex is dissociated by a helicase called Rho

Answer 22

termination

Question 23

Differences between prokarytoic and eukaryotic transcription

Answer 23

prokaryotes:

• 1 RNA pol.
• no RNA processing
• Coupled transcription and translation
• polycistronic RNA

Eukaryotes:

• 3 RNA
• Introns removed
• Transcription and translation not coupled
• Nuclear export (due to nuclear envelope & membrane)
• Capping
• Polyadenlation
• monocistronic RNA

Question 24

Many genes encoded in same RNA molecule.

prokaryotes

Answer 24

Polycistronic

Question 25

One gene encoded in same RNA molecule. | eukaryotes

Answer 25

Monocistronic

Question 26

RNA pol I in Eukaryotes

Answer 26

RNA in nucleolus

Question 27

RNA pol II in Eukaryotes

Answer 27

mRNA + snRNA | -found in nucleoplasm

Question 28

small nuclear RNA - their primary function is in the processing of pre-mRNA in the nucleus. - They have been shown to aid in the regulation of transcription factors, and maintaining the telomeres.

Answer 28

snRNA

Question 29

RNA pol III in Eukaryotes

Answer 29

tRNA + one kind of rRNA | found in nucleoplasm

Question 30

Polymerases in Eukaryotes

Answer 30

1. RNA pol I 2. RNA pol II 3. RNA pol III - none can bind directly to DNA, need txn factors

Question 31

Major steps in transcription

Answer 31

1. Initiation 2. Elongation 3. Termination

Question 32

Step 1: Initiation in Eukaryotes

Answer 32

- general transcription factors bind to the core promoter | - GTFs recruit polymerase to form the preinitiation complex (PIC)

Question 33

Are name according to the polymerase the recruit. | ex TF II A where II= RNA pol II interacion and A=1st to be discovered

Answer 33

General Transcription Factors

Question 34

Recruitment of polymerase by GTFs is __________.

Answer 34

increased by activators bound to enhancer sequences.

Question 35

A region of DNA that recognizes the transcription machinery and binds one or more proteins that regulate transcription initiation. - are necessary for transcription to be initiated accurately and at a basal level. - located immediately adjacent to the genes they regulate.

Answer 35

Promoter

Question 36

Subcategories within Eukaryotic promoter

Answer 36

1. Core Promoter | 2. Proximal Promoter Elements

Question 37

Determines the accurate initiation of transcription by RNA pol. II

Answer 37

Core promoter

Question 38

Modulate the efficinecy of basal levels of transcription.

Answer 38

Proximal promoter elements

Question 39

These proteins bind to genes at sites known as enhancers and speed the rate of transcription

Answer 39

Activators

Question 40

These proteins bind to selected sets of genes at all sites known as silencers and thus slow transcription

Answer 40

Repressors

Question 41

These "adapter" molecules integrate signals from activators and perhaps repressors

Answer 41

Coactivators

Question 42

In response to injunctions from activators, these factors position RNA pol. at the start of transcription and initiate the transcription process.

Answer 42

Basal transcription factors

Question 43

Step 2: Elongation in Eukaryotes

Answer 43

- RNA pol. II can denature DNA to form a transcription bubble * catalyzes NTP addition to 3' end of RNA * during transcription (cotranscriptionally): 1. 5' methyl G cap added to RNA 2. Splicing of introns

Question 44

Short nucleotide sequences that bind specific regulatory factors

Answer 44

Promoter Elements

Question 45

Sequence that is located on the same chromosome as the gene that it regulates

Answer 45

Cis-acting sequence

Question 46

Can regulate a gene on any chromosome | -ex. DNA-binding protein

Answer 46

Trans-acting factors

Question 47

- Protect RNA from exonucleases - Correct position of ribosome during translation - Exonucleases cannot work with this 5' to 5' linkage

Answer 47

5' methyl G capping

Question 48

Many eukaryotic genes contain long insertions of non-coding sequences called ________. - intervening - transcribed but not translated

Answer 48

Introns

Question 49

Expressed sequence | -transcribed and often times translated

Answer 49

Exons

Question 50

Complex of proteins and RNA that performs the removal of introns

Answer 50

Spliceosome

Question 51

Step 3: Termination in Eukaryotes through polyadenylation

Answer 51

- mRNA is cleaved at a polyA site - mRNA released - 50 to 250 adenine nucleotides added to the 3' end by polyA polymerase * protection from 3' to 5' exonucleases * aids in translation

Question 52

Structure of a mature eukaryotic mRNA

Answer 52

5' cap-------5' UTR-------protein coding region--------3' UTR-------3' polyA tail * UTR= untranslated region * translational start site btwn 5' UTR and protein coding region * translational stop site btwn 3' UTR and protein coding region

Question 53

The polyA tail of mRNAs __________. a. is added to the 3' end of mRNAs b. is found on mature eukaryotic mRNAs c. is added at the end of transcription d. helps prevent degradation of eukaryotic mRNAs e. all of the above are correct

Answer 53

e. all of the above are correct