RNA Synthesis- transcription

Question 1

gene expression

Answer 1

the process by which DNA directs protein synthesis, two stages transcription and translation

Question 2

transcription

Answer 2

synthesis of RNA from DNA (genes)

Question 3

translation

Answer 3

the synthesis of a polypeptide

Question 4

codon

Answer 4

3 bases

Question 5

how is mRNA produced in prokaryotes

Answer 5

by transcription it is immediately translated without processing

Question 6

what happens at same time in bacteria

Answer 6

transcription and translation

Question 7

when does translation start in bacteria

Answer 7

before transcription even stops
the mRNA is translated by ribosomes while it is still being transcribed from DNA by RNA Pol

Question 8

RNA Processing

Answer 8

eukaryotic primary RNA transcripts are modified to yield mRNA

Question 9

how is transcription and translation separated in eukaryotes

Answer 9

in space and time

Question 10

RNA synthesis : transcription in prokaryotes

Answer 10

is the process of generating an RNA molecule from DNA

Question 11

what is RNA synthesis catalysed by ?

Answer 11

RNA polymerase

Question 12

does RNA need a primer

Answer 12

no

Question 13

what is the DNA sequence where RNA polymerase attaches called

Answer 13

the promoter

Question 14

initiation

Answer 14

After RNA Pol binds to the promoter it unwinds and opens short segments of the DNA strands.
RNA pol synthesises ssRNA complementary to the template strand
RNA synthesis starts de novo without the requirement of a primer

Question 15

Elongation

Answer 15

RNA Pol moves along the gene, synthesising RNA
the new RNA forms a helix with the DNA
RNA-DNA hybrid separate
RNA chain exits the enzyme and the DNA chain rejoins
the DNA is unwound ahead and rewound behind by RNA pol

Question 16

what forces the RNA-DNA hybrid to separate ?

Answer 16

the structure within RNA pol

Question 17

Termination

Answer 17

RNA Pol reaches a termination site
RNA pol released
mRNA released
DNA is in its original form

Question 18

can a single gene be transcribed simultaneously by several molecules of RNA pol

Answer 18

yes

Question 19

how many RNA copies are produced from a single gene?

Answer 19

many

Question 20

all RNA is eventually what and replaced

Answer 20

degraded

Question 21

termination sequence

Answer 21

palindromic GC rich followed by a run of adenylates in template strand
hairpin is formed
Poly (A=u) at end of RNA is unstable
RNA-DNA dissociate
RNA released
RNA pol falls off
DNA associates

Question 22

what forms a hairpin

Answer 22

RNA transcripts of the DNA palindromes

Question 23

what does hairpin loop do

Answer 23

causes RNA POl to pause

Question 24

what component is at the start of gene ?

Answer 24

promoter

Question 25

what function does RNA polymerase carry out

Answer 25

It binds to the promoter, It unwinds the DNA locally, It matches RNA nucleotides to the DNA template, It forms the sugar-phosphate bonds between RNA nucleotides.

Question 26

what direction is RNA synthesised

Answer 26

5'-3'

Question 27

what does the termination sequence do when its transcribed

Answer 27

it signals RNA pol to stop

Question 28

name of first molecule translated in a cell ?

Answer 28

primary RNA transcript

Question 29

can we translate primary rna transcript

Answer 29

no, it needs to be processed before it is translated

Question 30

where does translation occur ?

Answer 30

cytoplasm at ribosomes