Lecture 15 - Transcription

Question 1

What two types of structures does RNA have?

Answer 1

Primary and Secondary

Question 2

What does two distinct 3’ and 5’ ends signify in RNA

Answer 2

Polarity

Question 3

What does a primary structure look like for RNA?

Answer 3

linear

Question 4

What does the secondary structure look like for RNA?

Answer 4

folded

Question 5

Where is the hydroxyl group located in RNA?

Answer 5

2’ carbon

Question 6

What direction does synthesis go for RNA?

Answer 6

5’ –> 3’

Question 7

True or false: DNA is more stable than RNA

Answer 7

True

Question 8

What types of RNA is found in both Prokaryotes and Eukaryotes?

Answer 8

mRNA, rRNA, tRNA

Question 9

What does rRNA do?

Answer 9

It’s the functional and structural components of a ribosome

Question 10

What does mRNA do?

Answer 10

Carries genetic code for proteins

Question 11

What does tRNA do?

Answer 11

Helps incorporate amino acids into polypeptide chain

Question 12

What cell is a snRNA found in?

Answer 12

Eukaryotic

Question 13

What do snRNAs do?

Answer 13

process pre-mRNA

Question 14

Where are lncRNAs found?

Answer 14

Eukaryotic

Question 15

Where is crRNA and what does it do?

Answer 15

Prokaryotic and assists in detecting foreign DNA

Question 16

What do snoRNA do?

Answer 16

process and assemble rRNA

Question 17

What do siRNA do?

Answer 17

trigger degradation of other RNA molecules

Question 18

What do piRNA do?

Answer 18

suppress transcription of transposable elements in reproductive cells

Question 19

Which of the following is not found in eukaryotes?
a. snRNA
b. snoRNA
c. miRNA
d. crRNA
e. piRNA
f.lncRNA

Answer 19

d. crRNA

Question 20

What does the “brush” represent in this EM image?

Answer 20

RNA molecules

Question 21

What does the spine represent in this EM image?

Answer 21

DNA molecules

Question 22

What is the transcribed strand called?

Answer 22

template

Question 23

What strand does the RNA use as a template and what direction is it read?

Answer 23

The lower strand (3’ –> 5’)

Question 24

What can the upper, nontemplate strand also be referred to as?

Answer 24

coding strand or sense strand

Question 25

What is the coding strand identical to?

Answer 25

sequence in the transcript (except T is U)

Question 26

What is the lower, template strand also referred to as?

Answer 26

noncoding strand or antisense strand

Question 27

True or false: RNA molecules are added 3 at a time

Answer 27

False, they are individually added to the 3' end of the RNA

Question 28

What does the transcription unit not contain?

Answer 28

promoter

Question 29

In what order do pieces of the 5', nontemplate strand go?

Answer 29

promoter --> transcription start site --> RNA coding region --> terminator --? transcription termination site

Question 30

What is a ribonucleoside triphosphate (rNTPs)?

Answer 30

building blocks of RNA

Question 31

What are the 5 subunits in RNAP

Answer 31

alpha(2), beta(1), beta prime(1), omega(1)

Question 32

What does the sigma factor do?

Answer 32

Controls the binding to the promoter so initiation begins at the transcription initiation site.

Question 33

What three classes of RNA polymerases (RNAPs) are found in all eukaryotes?

Answer 33

RNAP I, RNAP II, RNAP III

Question 34

What RNAPs are only found in plants?

Answer 34

RNAP IV, RNAP V

Question 35

What are the accessory proteins in RNAP polymerase classes called?

Answer 35

Transcription Factors

Question 36

What gene to RNAP I transcribe?

Answer 36

Large rRNAs

Question 37

What gene do RNAP II transcribe?

Answer 37

pre-mRNA, snRNAs, snoRNAs, miRNAs

Question 38

What gene do RNAP III transcribe?

Answer 38

tRNAs, small rRNAs, snRNAs, miRNAs

Question 39

What gene do RNAP IV transcribe?

Answer 39

siRNA

Question 40

What gene do RNAP V transcribe?

Answer 40

RNA molecules taking part in heterochromatin formation

Question 41

What are the three steps involved in bacterial transcription?

Answer 41

Initiation, Elongation, Termination

Question 42

What happens in the initiation step?

Answer 42

The transcription apparatus assembles at the promoter (INITIATES RNA SYNTHESIS)

Question 43

What happens in the elongation step?

Answer 43

DNA is threaded through RNA polymerase, RNAP unwind DNA and add new ribonucleotides (ONE AT A TIME TO THE 3' END)

Question 44

What happens during the termination step?

Answer 44

The termination site is recognized and releases RNA product from DNA template

Question 45

When does the transcription bubble form?

Answer 45

Initiation in bacterial transcription

Question 46

When are the first phosphodiester bonds formed between rNTPs?

Answer 46

initiation

Question 47

What do promoters determine?

Answer 47

Where, when and the extent that genes get transcribed

Question 48

True or False: Promoters contain consensus sequences

Answer 48

True

Question 49

What serves as a binding site for RNAP

Answer 49

promoters

Question 50

How many consensus sequences are found in bacterial promoters?

Answer 50

2

Question 51

TATAAT has how many consensus sequences?

Answer 51

-10, 10 bp upstream of start site

Question 52

TTGACA has how many consensus sequences?

Answer 52

-35

Question 53

What are TTGACA recognized by?

Answer 53

RNAP holoenzymes and sigma factors

Question 54

What does the spacing of the consensus sequence determine?

Answer 54

Which DNA strand serves as a template, the direction of synthesis

Question 55

What is the transcription initiation site determined by?

Answer 55

the position of the consensus sequences

Question 56

How many nucleotides are are transcription bubbles?

Answer 56

~18 nucelotides are unwound

Question 56

How many nucleotides are are transcription bubbles?

Answer 56

~18 nucelotides are unwound

Question 57

When is supercoiling introduced into the DNA?

Answer 57

as the transcription bubble moves

Question 58

True or False: Transcriptional pausing occurs in primary structures

Answer 58

False, it occurs in secondary structures or specific sequences

Question 59

What does RNAP do when misincorporation occurs?

Answer 59

It backtracks, cleaves out the last 2 nucleotides and proceeds transcribing forward

Question 60

When and how does the hairpin structure form?

Answer 60

During Rho-Termination and by inverted repeats and a line of uracil

Question 61

What is polycistronic mRNA

Answer 61

Bacteria that frequently transcribed a group of genes in a single RNA molecule