ch 5

Question 1

Central Dogma of Molecular Biology

Answer 1

DNA used as instructions for RNA
RNA used as instructions for proteins

Question 2

main steps of trasnscription

Answer 2

1. initiation
2. elongation
3. termination

Question 3

initiation (transcription)

Answer 3

proteins attach to DNA and open the two strands

transcription factors bind gene at promoter
attracts RNA polymerase

Question 4

elongation (transcription)

Answer 4

new RNA polymer is produced and extended

Question 5

termination (transcription)

Answer 5

RNA molecule gets detached and process is over

Question 6

promotor region

Answer 6

broad term, DNA sequence that shows RNA polymerase where to initiate transcription

contains promoter elements

Question 7

T/F: different genes have different promoter elements

Answer 7

true

Question 8

promoter elements

Answer 8

nucleotide sequence that attracts a specific transcription factor

Question 9

transcription factors ultimately recruit _______

Answer 9

RNA polymerase

Question 10

how many RNA polymerases do humans have

Answer 10

4

3 in nucleus
1 in mitochondria

Question 11

function of RNA polymerase

Answer 11

transcribe different gene types

Question 12

what brings RNA Pol II to promoters

Answer 12

transcription factors called TFIID
TFIID recruits TFIIB
TFIIB recruits RNA Pol II

Question 13

function of TFIIH

Answer 13

helicase function
opens DNA so transcription can begin

Question 14

mediator complex

Answer 14

multiple proteins
helps hold everything together
helps release RNA Pol II to begin elongation

Question 15

pre-initiation complex

Answer 15

full complex of factors necessary to start transcription
all the components in the circle

Question 16

what causes RNA Pol II to be released

Answer 16

mediator enables RNA Pol II to be phosphorylated

Question 17

antisense strand

Answer 17

template strand of DNA
RNA is complementary to it

Question 18

sense strand

Answer 18

other strand of DNA (not template)
RNA is the same as it

Question 19

what direction does RNA polymerase add nucleotides

Answer 19

5’ to 3’

Question 20

carboxyl terminal region

Answer 20

long intrinsically disordered trail on RNA polymerase

Question 21

polyadenylation signal

Answer 21

DNA sequence that initiates termination in transcription

Question 21

function of carboxyl region on RNA polymerase

Answer 21

platform for other proteins to bind
helps with elongation factors (helps with RNA processing)

Question 22

termination steps

Answer 22

1. Pol II transcribes polyadenylation signal
2. signal recruits endonuclease

Question 23

exonuclease

Answer 23

degrades RNA after polyadenylation signal

during termination of transcription

Question 23

endonuclease

Answer 23

enzyme that cuts mRNA in transcription

Question 24

torpedo model

Answer 24

exonuclease runs into and detaches polymerase during termination of transcription

Question 25

T/F: new RNAs must undergo maturation/processing

Answer 25

true

Question 26

precursor RNA

Answer 26

initial RNA before RNA processing not ready to do its job

Question 27

mature RNA

Answer 27

RNA after maturation/processing ready to function

Question 28

4 main events of processing mRNA

Answer 28

1. addition of 5' cap 2. 3' polyadenylation 3. splicing 4. editing/modification

Question 29

RNA capping

Answer 29

inverted guanine added to 5' end of new RNA prevents RNA from being degraded by nucleases

Question 30

3' polyadenylation

Answer 30

~200 adenines added to 3' end of mRNA helps stabilize mRNA regulate translation

Question 31

poly-A tail

Answer 31

~200 adenines added to 3' end of mRNA

Question 32

RNA splicing

Answer 32

process that removes unnecessary segments

Question 33

introns

Answer 33

regions that are removed

Question 34

exons

Answer 34

regions that are retained

Question 35

how much of the typical human gene is introns

Answer 35

~90%

Question 36

in mRNAs, only _______ will be translated

Answer 36

exons

Question 37

alternative splicing

Answer 37

exons spliced together in different combinations

Question 38

isoforms

Answer 38

different versions of a protein that are produced from the same gene via alternative splicing

Question 39

Dscam

Answer 39

gene involved in brain function in drosophila

Question 40

T/F: introns can contain sequences that regulate transcription

Answer 40

true

Question 41

spliceosome

Answer 41

complex that removes introns made up of multiple RNA-protein complexes

Question 42

RNA modification

Answer 42

some nucleotides are chemically modified

Question 43

another name for RNA modification

Answer 43

post-transcriptional modification influences RNA functions

Question 44

RNA degradation

Answer 44

break down of RNA molecules via nucleases

Question 45

how long does an RNA molecule last in cells

Answer 45

about 12 hours