RNA and transcription W4

Question 1

three main differences between RNA and DNA

Answer 1

RNA is single stranded
it contains Uracil instead of thymine
it contains ribose instead of deoxyribose

Question 2

three main RNA species

Answer 2

messenger RNA (mRNA)
ribosomal RNA (rRNA)
transfer RNA (tRNA)

Question 3

primary role of mRNA

Answer 3

directs amino acid sequence for proteins

Question 4

primary role of tRNA

Answer 4

transports amino acids to site of protein synthesis

Question 5

primary role of rRNA

Answer 5

part of ribosome, involved in protein synthesis

Question 6

how is RNA made

Answer 6

via RNA polymerase

Question 7

what directs the transcription process

Answer 7

DNA sequence

Question 8

what is a promoter

Answer 8

start signal - TATA box: 5’TATAAA3’

Question 9

what is the start signal recognised by

Answer 9

TATA protein (TBP)

Question 10

what is the terminator

Answer 10

stop signal- 5’ AATAAA 3’ signals polymerase to stop

Question 11

what controls the rate of transcription

Answer 11

transcription factors

Question 12

what do transcription factors do

Answer 12

regulate the rate of transcription

Question 13

how do transcription factors regulate the rate of transcription

Answer 13

by binding to specific DNA sequences in promter regions (DNA BINDING DOMAIN) and interract with proteins that are required for transcription to alter rate (ACTIVATION/REPRESSION DOMAIN)

Question 14

what are the two types of transcription factors

Answer 14

general

specific

Question 15

what is the difference between general and specific transcription factors

Answer 15

general - needed for transcription to occur, same ones required for all genes and cells

specific- not needed for transcription to occur, but they increase/decrease the rate`

Question 16

specific transcription factors may be involved in …… or…..

Answer 16

activation or repression

Question 17

specific transcription factors can be regulated by (3)

Answer 17

• cell specific expression
• translocation
• modification or binding interactions with other proteins

Question 18

example of specific transcription factor

Answer 18

steroid hormone receptor -

only prompters with steroid responsive element will respond

Question 19

specific example of specific transcription factors (2)

Answer 19

androgen prompter

estrogen prompter

Question 20

two examples of chemical modification of RNA

Answer 20

%’ cappin: methylated guanine cap prevents immediate degradation

addition of poly-A-tail prevents immediate

Question 21

what’s the difference between pre mRNA and mature mRNA

Answer 21

mature RNA is only composed of exons

Question 22

what is splicing

Answer 22

the removal of non-coding introns

Question 23

whats alternative splicing

Answer 23

splicing where particular exons are excluded or included

Question 24

how can different mRNA (and hence proteins) be formed from the a single gene

Answer 24

through alternative splicing (the inclusion or exclusion of specific exons

Question 25

how does a cell know where an intron starts and ends ??

Answer 25

intron concensus sequence | GU....AG

Question 26

intron consensus sequence, GU end is called .... | AG end is called ,,,

Answer 26

donor site acceptor site

Question 27

what does it stand for: snRNPs

Answer 27

small nuclear ribonucleoproteins

Question 28

what do snRNPs do?

Answer 28

they pull exons together, forming intronic loop which is cleaved and therefore the exons are spliced together

Question 29

what is an intronic loop

Answer 29

loop made from the intron section of pre mRNA which is then cleaved to form mature mRNA

Question 30

DNA- 4 main problems that lead to disease

Answer 30

- mutation in non-coding regions - alterations in transcriptional activity - non coding RNAs - splice variants

Question 31

how do mutations in non coding regions lead to disease

Answer 31

mutations in transcription factor binding sites may lead to an increase/decrease in protein production

Question 32

how do non coding RNAs lead to disease

Answer 32

bind to complementary sequence and target mRNA for degradation which may impact the leves of protein

Question 33

how can splice variants lead to disease

Answer 33

can cause proteins with altered functions

Question 34

example of disease resulting from alternative splicing

Answer 34

hutchinson-guilford pregoria syndrome