Chapter 14

Question 1

Transcription

Answer 1

DNA sequence is copied to a complementary
RNA sequence

Question 2

Translation

Answer 2

RNA sequence is template for an amino acid sequence

Question 3

mRNA (messenger RNA)

Answer 3

one strand of DNA is copied to a complementary mRNA strand, moves to cytoplasm in eukaryotes

Question 4

rRNA (ribosomal RNA)

Answer 4

catalyzes peptide bond formation between amino acids to form a polypeptide

Question 5

tRNA (transfer RNA)

Answer 5

binds specific amino acids and recognizes specific
sequences in mRNA

Question 6

4 things needed for transcription

Answer 6

1. DNA template for base pairings
2. ATP, GTP, UTP, CTP (ribonucleoside phosphates)
3. RNA polymerase
4. Salts and pH buffer (test tube only)

Question 7

RNA polymerase

Answer 7

catalyzes RNA synthesis

Question 8

processive

Answer 8

one enzyme‐template binding results in polymerization of hundreds of RNA bases

Question 9

steps of Transcription

Answer 9

1. initiation
2. elongation
3. termination

Question 10

promotor

Answer 10

tell enzyme where to start and which strand of DNA to
transcribe

Question 11

initiation site

Answer 11

where transcription begins

Question 12

Sigma Factors (prokaryotes) /transcription factors (eukaryotes)

Answer 12

proteins that bind to DNA sequences and RNA polymerase, helping
direct polymerase onto the promoter

Question 13

Describe initiation in transcription

Answer 13

RNA polymerase binds to a DNA promotor sequence

Question 14

Describe elongation in transcription

Answer 14

RNA polymerase unwinds DNA about 10 base pairs at a time;
reads template DNA strand in 3’ to 5’ direction

Question 15

describe termination in transcription

Answer 15

where transcription stops; specified by a specific DNA
sequence

Question 16

Intron

Answer 16

noncoding regions that are
transcribed but then spliced out of
pre‐mRNA in the nucleus

Question 17

Exons

Answer 17

coding sequences; reach the
ribosome

Question 18

RNA splicing

Answer 18

removes introns
and splices exons together

Question 19

Small nuclear
ribonucleoprotein particles
(snRNPs)

Answer 19

remove introns from pre-mRNA and splice the exons together

Question 20

5’ cap

Answer 20

facilitates binding to the ribosome

Question 21

poly A tail

Answer 21

a long chain of adenine nucleotides that is added to a messenger RNA to increase stability

Question 22

Genetic code

Answer 22

specifies which amino acids will be used to build a protein

Question 23

codon

Answer 23

sequence of three bases, each specifying a particular amino acid

Question 24

How to read a codon chart

Answer 24

first letter on the left, seconded on top, third on the right

Question 25

Start codon

Answer 25

initiation signal for translation

Question 26

stop codon

Answer 26

termination signal

Question 27

Wobble

Answer 27

specificity for the base at the 3’ end of the codon is not always observed

Question 28

Aminoacyl‐tRNA synthetases

Answer 28

enzymes that charge tRNA

Question 29

steps of Translation

Answer 29

1. initiation 2. elongation 3. termination

Question 30

initiation complex

Answer 30

a charged tRNA and small ribosomal subunit, both bound to mRNA

Question 31

describe initiation in translation

Answer 31

small ribosomal subunit binds to mRNA, a tRNA charged with methionine (with anticodon UAC), binds to start codon (AUG), large subunit joins, charged tRNA in now in the P site

Question 32

describe elongation in translation

Answer 32

another charged tRNA enters the A site, while at the p site, the methionine is transferred to the end of the next charged amino acid on the tRNA in the A site, then the first tRNA is moved to the e site where it is ejected, and the A site tRNA moves to P site and the cycle continues

Question 33

describe termination in translation

Answer 33

translation ends when a stop codon enters the A site, Stop codons bind a protein release factor, which hydrolyzes the bond between the polypeptide and the tRNA in the P site, then the polypeptide separates from the ribosome.

Question 34

elongation factors

Answer 34

protein that assists in repeating elongation steps

Question 35

polyribosome

Answer 35

a strand of mRNA with associated ribosomes