Chapter 17

Question 1

transcription

Answer 1

transcribe DNA into RNA

Question 2

prompter

Answer 2

signal to start transcribing
- codon of 3 nucleotides

Question 3

how many types of RNA polymerase do bacteria and eukaryotes have

Answer 3

bacteria= 1
eukaryotes- 3 (I, II, III)

Question 4

initiation (transcription)

Answer 4

RNA polymerase attaches to promoter

Question 5

elongation (transcription)

Answer 5

RNA grows longer
- RNA polymerase moves along DNA

Question 6

as RNA peels away, what happens (transcription)

Answer 6

DNA strand rejoins

Question 7

termination (transcription)

Answer 7

RNA polymerase reaches sequence of based in DNA template to signal end of gene

Question 8

what happens after termination in transcription

Answer 8

polymerase detaches from RNA molecule & gene

Question 9

mRNA

Answer 9

encodes amnio acid sequences
- conveys genetic message from DNA

Question 10

what does eukaryotic mRNA have

Answer 10

introns- interrupting sequences that separate
exons- coding regions

Question 11

what does transcription end with

Answer 11

termination

Question 12

what are introns considered

Answer 12

white noise

Question 13

terminator

Answer 13

signals end of gene

Question 14

sigma

Answer 14

protein that must bind promoter first & form holoenzyme
- recognizes & binds to promoter

Question 15

core enzyme

Answer 15

RNA polymerase because it has active site

Question 16

how are introns removed

Answer 16

splicing

Question 17

spliceosome & splicing

Answer 17

cut out extra information that isn’t needed
- allows different mRNAs & proteins to be produced from single gene

Question 18

in eukaryotes, what does splicing do

Answer 18

remove introns & joins exons

Question 19

pre-mRNA

Answer 19

primary transcript
- in bacteria mRNA are translated immediately & transcript is an immature primary transcript before transcription is complete

Question 20

ribosomes

Answer 20

site of protein synthesis
- where translation happens

Question 21

polyribosome

Answer 21

multiple ribosomes attached to an mRNA

Question 22

in eukaryotes, how are mature mRNAs transported to cytoplasm

Answer 22

by ribosomes

Question 23

where does translation occur

Answer 23

on surface of ribosome

Question 24

what are the two subunits of ribosomes

Answer 24

small- holds mRNA in place
large- where peptide bonds form

Question 25

what is the structure of ribosomes

Answer 25

contain many proteins, ribosomal RNA (rRNA), and can be separated into 2 subunits

Question 26

what lines up with ribosomes during translation

Answer 26

three tRNAs

Question 27

what are the 3 sites in the ribosome

Answer 27

- A site - P site - E site

Question 28

A site

Answer 28

acceptor site for aminoacyl tRNA

Question 29

P site

Answer 29

peptidyl site where a peptide bond forms

Question 30

E site

Answer 30

where tRNAs without amino acids exit the ribosome

Question 31

transfer RNA (tRNA)

Answer 31

function as language interpreter - convert genetic message of mRNA into language of proteins

Question 32

how does tRNA perform the interpreter task

Answer 32

pick up appropriate amino acid using an anticodon to recognize the appropriate codons in the mRNA

Question 33

aminoacyl tnRNA

Answer 33

tRNA linked to its amino acid

Question 34

what is the structure of tRNA

Answer 34

- relatively short - can form secondary structure by folding - CCA sequence at 3' end is binding site for amino acids

Question 35

aminoacyl-tRNA synthetases

Answer 35

enzymes that "charge" the tRNA by catalyzing the addition of amino acids to tRNAs - adds amino acids onto tRNA

Question 36

for 61 different codons, how many tRNA are there

Answer 36

about 40 tRNAs

Question 37

wobble hypothesis

Answer 37

- Crick - tRNA can grab more than 1 ingredient - anticodon of tRNAs can still bind successfully to a codon whose third position doesn't follow traditional base pair rules

Question 38

what do ribosomes provide for mRNA and tRNA

Answer 38

binding sites - subunits and binding sites come together

Question 39

anticodon

Answer 39

figures out what amino acid codons are coding for

Question 40

ribosomal RNA (rRNA)

Answer 40

involved in protein synthesis - helps align mRNA & tRNA on ribosome & catalyzes the formation of peptide bonds

Question 41

polypeptide chain

Answer 41

strand of amino acids linked by peptide bonds

Question 42

ribosome binding site

Answer 42

where the small ribosomal subunit bind to the mRNA

Question 43

initiation factors

Answer 43

control whether initiation can begin or not

Question 44

translocation

Answer 44

occurs when ribosome slides one codon toward the 3' end of mRNA

Question 45

release factor

Answer 45

- protein - enters the A site - does not carry an amino acid - hydrolyzes the bond linking the P-site tRNA to polypeptide chain - binds to stop codon in terminating translation

Question 46

molecular chaperones

Answer 46

speed protein folding

Question 47

what are the three phases of translation

Answer 47

initiation- gets translation to start elongation- going through A, P, & E to build out chain termination- stop codon

Question 48

how is translation initiated in bacteria

Answer 48

- mRNA binds to small ribosomal unit - initiator tRNA bearing f-Met binds to start codon - large ribosomal subunit binds so initiator tRNA is in P site

Question 49

what are the stages of transcription

Answer 49

initiation elongation RNA peels away termination

Question 50

transcription in bacteria

Answer 50

sigma protein mist bind prompter first RNA polymerase & sigma form a holoenzyme

Question 51

what happens in bacteria before transcription is complete

Answer 51

ribosomes being translating an mRNA