From DNA to RNA

Question 1

DNA does not direct protein synthesis directly, instead it copies into RNA:

Answer 1

transcription

Question 2

RNA copies of DNA segments direct synthesis of protein:

Answer 2

translation

Question 3

what is the Central Dogma aka fundamental process?

Answer 3

DNA to RNA to protein

Question 4

what is rna?

Answer 4

linear polymer made of 4 diff nucleotides

Question 5

on uracil, the absence of its methyl group has no effect on base pairing but can affect what?

Answer 5

DNA repair

Question 6

what are mRNAs?

Answer 6

messenger RNAs, code for proteins

Question 7

rRNAs?

Answer 7

ribosomal RNAs, form the basic structure of the ribosome; catalyze protein synthesis

Question 8

tRNAs?

Answer 8

transfer RNAs, central to protein synthesis as the adaptors bw mRNA and amino acids

Question 9

telomerase RNA?

Answer 9

serves as the template for telomerase enzyme that extends the ends of chromosomes

Question 10

snRNAs?

Answer 10

small nuclear RNAs, function in a variety of nuclear processes, including splicing of pre-mRNAs

Question 11

snoRNAs?

Answer 11

small nuclear RNAs, help to process and chemically modify rRNAs

Question 12

IncRNAs

Answer 12

long encoding RNAs, not all of which have a function; some serve as scaffolds and regulate diverse cell processes, including X-chromosome inactivation

Question 13

miRNAs?

Answer 13

microRNAs, regulate gene expression by blocking translation of specific mRNAs and causing their degradation

Question 14

siRNAs

Answer 14

small interfering RNAs, turn off gene expression by directing the degradation of selective mRNAs and helping to establish repressive chromatin structures

Question 15

piRNAs

Answer 15

Piwi-interacting RNAs, bind to piwi proteins and protect the germ line from transposable elements

Question 16

what is a transcription unit?

Answer 16

a transcribed segment of DNA; info in just one gene for just one RNA molecule or single protein

Question 17

what 3 RNA polymerases are involved in transcription?

Answer 17

RNA pol I,II, III

Question 18

what are general transcription factors?

Answer 18

proteins that initiate transcription

Question 19

sequence of DNA nucleotides that signal the starting point for RNA synthesis

Answer 19

promoter

Question 20

how are introns removed?

Answer 20

splicing

Question 21

how are exons joined?

Answer 21

with help of small nuclear RNAs (snRNAs)

Question 22

how much RNA in eukaryotic cells is rRNA?

Answer 22

80%

Question 23

why are general transcription factors used?

Answer 23

RNA polymerases require them to initiate transcription; DNA packaging into nucleosomes is a problem

Question 24

how does a supercoil form?

Answer 24

for every 10 nucleotides open, a supercoil forms

Question 25

what causes a dna supercoil to form?

Answer 25

elongation, bc of the need to unwind the helix

Question 26

what helps remove the tension in transcription to help prevent coiling?

Answer 26

DNA topoisomerase

Question 27

where do transcriptional activators bind?

Answer 27

“enhancer” sequences

Question 28

what is required so that activators can communicate with transcription complex?

Answer 28

mediator

Question 29

when are chromatin and remodeling proteins/enzymes recruited?

Answer 29

with mediator

Question 30

what determines when RNA pol will dissociate from the helix?

Answer 30

elongation factors

Question 31

proteins that decrease the likelihood that RNA pol will dissociate before it reaches end of a gene

Answer 31

elongation factors

Question 32

what two impediments does transcription elongation face?

Answer 32

nucleosomes and DNA supercoiling

Question 33

in what direction is transcription?

Answer 33

5’ to 3’ (like replication)

Question 34

how many strands are used as template in transcription?

Answer 34

one

Question 35

RNA pol II is also known as what?

Answer 35

rna synthesis and processing machine

Question 36

only exons are transcribed into RNA. T or F?

Answer 36

false, both introns and exons are transcribed

Question 37

how are introns removed?

Answer 37

by splicing

Question 38

Exons are joined with help of what? (these recognize splice sequence)

Answer 38

small nuclear RNAs (snRNAs)

Question 39

what do snRNPs form?

Answer 39

form the core of the “spliceosome”

Question 40

splicing is flexible if alternative proteins need to be made / mutations present in the gene

Answer 40

alternative splicing

Question 41

what are the 3 ways alternative splicing occurs in disease?

Answer 41

exon skipping, activating cryptic splice site, creates new splice site

Question 42

what happens to mature mRNAs?

Answer 42

transported from nucleus to cytoplasm

Question 43

most abundant type of RNA (80%)

Answer 43

rRNA

Question 44

what transcribes rRNAs?

Answer 44

rna pol I