Lippincott - RNA Structure, Synthesis, Processing

Question 1

3 major types of RNA participating in protein synthesis

Answer 1

tRNA
mRNA
rRNA

Question 2

difference of RNA from DNA

Answer 2

[1] contain ribose instead of deoxyribose
[2] contain uracil instead of thymine
[3] exist as single strands
[4] capable of folding into complex structure

Question 3

rRNA

Answer 3

components of ribosomes

Question 4

rRNA species in eukaryotic cells

Answer 4

28S, 18S, 5.8S, 5S

Question 5

tRNA

Answer 5

carries amino acids to be used in translation

Question 6

mRNA

Answer 6

[1] carries genetic information from nuclear DNA to the cytosol
[2] used as a template for protein synthesis

Question 7

steps in RNA synthesis

Answer 7

[1] initiation
[2] elongation
[3] termination

Question 8

important event in initiation

Answer 8

binding of RNA polymerase to promoter

Question 9

direction of transcription

Answer 9

5’–>3’

Question 10

3 types of RNA polymerase in eukaryotes

Answer 10

RNA polymerase I, II, III

Question 11

RNA polymerase I

Answer 11

synthesizes precursor of 28S, 18S, 5.8S rRNA

Question 12

RNA polymerase II

Answer 12

synthesizes mRNA precursors

Question 13

RNA polymerase III

Answer 13

synthesizes tRNA, 5S rRNA, snRNA, snoRNA

Question 14

promoter and consensus sequence for RNA polymerase II

Answer 14

TATA box, CAAT box

Question 15

other name for TATA box

Answer 15

Hogness box

Question 16

TFIID

Answer 16

recognizes and binds the TATA box

Question 17

TFIIF

Answer 17

brings polymerase to promoter

Question 18

TFIIH

Answer 18

[1] helicase activity melts DNA

[2] kinase activity phosphorylates polymerase, allowing it to clear the promoter

Question 19

GC box

Answer 19

found in genes that are constituitively expressed

Question 20

enhancers

Answer 20

[1] cis-acting DNA sequences that increase the rate of initiation of transcription by RNA polymerase II
[2] contain response elements that bind specific TFs that are transcription activators

Question 21

posttranscriptional modifiers of rRNA [2]

Answer 21

[1] ribonucleases

[2] exonucleases

Question 22

enzyme that adds CCA sequence to tRNA

Answer 22

nucleotidyltransferase

Question 23

where is the CCA sequence in tRNA attached?

Answer 23

3’ end

Question 24

major posttranscriptional modifications to mRNA [3]

Answer 24

[1] 5’ capping
[2] addition of poly A tail
[3] splicing

Question 25

composition of 5’ cap

Answer 25

7-methylguanosine

Question 26

linkage of 5’ cap

Answer 26

5’–>5’ triphosphate linkage

Question 27

enzymes in addition of 5’ cap

Answer 27

[1] guanylyltransferase - adds GMP

[2] guanine-7-methyltransferase - methylates GMP

Question 28

composition of poly A tail

Answer 28

40-200 adenosine nucleotides attached to 3’ end

Question 29

enzymes in addition of poly A tail

Answer 29

polyadenylate polymerase

Question 30

function of poly A tail [3]

Answer 30

[1] stabilize the mRNA
[2] facilitate exit from nucleus
[3] aid in translation

Question 31

correlation of poly A tail length and lifespan of the mRNA

Answer 31

longer poly-A-tails –> longer lifespan

Question 32

process of removing introns and joining exons

Answer 32

splicing

Question 33

responsible for splicing

Answer 33

spliceosome

Question 34

role of snRNAs in posttranscriptional modification of mRNA

Answer 34

snRNAs facilitate removal of introns by forming base pairs with the consensus sequences at each end of the intron, bringing the sequences of the neighboring exons into the correct alignment for splicing

Question 35

alternative splicing

Answer 35

formation of different isoforms through various splicing combinations