module 9

Question 1

__________: DNA > mRNA
_________: mRNA > Polypeptide

Answer 1

transcription
translation

Question 2

Boundaries of translation
are defined by ________ start codon that corresponds to the ___-terminus of the protein and a stop codon that
corresponds to the ___-terminus.

Answer 2

mRNA
N-terminus
C-terminus

Question 3

What are the segments of mRNA
outside of the translated regions referred to as?

Answer 3

5’ and 3’ untranslated regions
(5’ and 3’ UTR)

Question 4

What are the initiation sequences of bacteria called? eukaryotes?

Answer 4

Shine-Dalgarno (bacteria)
Kozak (eukaryotes

Question 5

mRNA is read 5ʹ to 3ʹ by the ___________

___________has N-terminus and C-terminus

Answer 5

ribosomes
polypeptides

Question 6

4 bases (AUCG) ╳ 3 bases per codon results in 4^3 which equals how many codons?

T/F Code is non-overlapping and universal

64 codons for how many standard amino acids?

Each codon specifies how many amino acids?

AUG is the start or stop codon?

UAG, UAA, and UGA start or stop codons?

code is ___________, but not ____________

Answer 6

64

TRUE

20

only a single amino acid

start codon (AUG)

stop (UAG, UAA, and UGA)

redundant; ambiguous

Question 7

Nirenberg and Matthaei, 1961, identified which codons?

Answer 7

Phe, Lys, Gly, Pro

Question 8

Khorana, 1961-1963 identified what?

Answer 8

identified additional codons, but ambiguous due to reading frame shifts

Question 9

What did Nirenberg and Leder, 1964 do?

Answer 9

tested and identified all 64 possible codons

Question 10

coding strand of DNA:
5ʹ - A T G G G G C C C T T T A A A T A G – 3ʹ

non-coding/template strand of DNA?
?ʹ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - ?ʹ

mRNA complement?
?ʹ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - ?ʹ

Polypeptide?
?-terminus - _ _ _ _ _ _ - ?-terminus

Answer 10

coding strand of DNA:
5ʹ - A T G G G G C C C T T T A A A T A G – 3ʹ

non-coding/template strand of DNA?
3ʹ - T A C C C C G G G A A A T T T A T C – 5ʹ

mRNA complement?
5ʹ - A U G G G G C C C U U U A A A U A G – 3ʹ

Polypeptide?
N-terminus - MET GLY PRO PHE LYS STOP - C-terminus

Question 11

a large molecule that contacts several points on the tRNA
in the recognition process

Answer 11

tRNA synthetase

Question 12

order these

separate tRNA synthetase for each of
the 20 amino acids

the acceptor stem of the correct tRNA fits
into the active site of the enzyme

▪ ATP provides the energy for amino acid
attachment

▪ the active site contains the amino acid
to be added to the tRNA

Answer 12

▪ the acceptor stem of the correct tRNA fits
into the active site of the enzyme

▪ the active site contains the amino acid
to be added to the tRNA

▪ ATP provides the energy for amino acid
attachment

▪ separate tRNA synthetase for each of
the 20 amino acids

Question 13

Third base wobble occurs through what at the 3’ most nucleotide of the codon and the 5’-most nucleotide of the
anticodon?

Answer 13

flexible pairing

Question 14

Most synonymous codons can
be grouped into pairs when?

pyrimidines base pair w?

Answer 14

differ only in third base

purines

Question 15

How many ribosomal proteins are in human, rat, and chicken?

Answer 15

67-74

Question 16

_______________________:
binds a new tRNA molecule
containing an amino acid to
be added to the chain

_______________: holds
the tRNA to which the
polypeptide is attached

__________________:
provides an avenue for exit of the
uncharged tRNA

Answer 16

Aminoacyl (A site)

Peptidyl (P Site)

Exit (E site)

Question 17

What forms when the 16s rRNA (of small subunit)
pairs with Shine–Dalgarno sequence on mRNA

Answer 17

preinitiation complex

Question 18

What forms the 30S initiation complex?

Answer 18

ssuRNA, mRNA and
initiator tRNA

Question 26

the initiator tRNA binds to what?

Answer 26

the start codon

Question 27

1. The amino acid on the initiator tRNA is what modified amino acid? 2. The charged initiator tRNA is called?

Answer 27

1. N formylmethionine (fMet); t 2. tRNAfMe

Question 28

together with several other initiation factors, the ssuRNA, mRNA and initiator tRNA form what?

Answer 28

the 30S initiation complex

Question 29

What joins the small (30S) subunit to form the intact ribosome?

Answer 29

large (50S) subunit

Question 30

The dissociation of initiation factors accompanies joining of the subunits to create what?

Answer 30

70S initiation complex

Question 31

What forms the pre-initiation complex?

Answer 31

small (40S) subunit complexes with eukaryotic initiation factor (eIF) proteins and initiator tRNA (tRNAMet

Question 32

What joins to form the initiation complex?

Answer 32

mRNA

Question 33

__________ moves the small subunit along the 5' UTR in search of the ________ codon

Answer 33

scanning; start codon

Question 34

~90% of eukaryotic mRNAs use what as the first start codon?

Answer 34

AUG

Question 35

start codon is embedded in a consensus sequence known as what?

Answer 35

Kozak sequence: 5'-ACCAUGG-3'

Question 36

The large (60S) subunit to the complex is recruited, using energy from what?

Answer 36

GTP hydrolysis, and dissociation of the eIF proteins

Question 37

In both prokaryotic and eukaryotic translation initiation, which is the last piece to ‘join the party’? a) small subunit of the ribosome b) 16S rRNA c) mRNA d) tRNA e) large subunit of the ribosome

Question 38

16S rRNA in bacterial small ribosomal subunits forms complementary base-pairing with which of the following during initiation of translation? a) Kozak sequence b) TATA box c) Shine-Dalgarno sequence d) 18S rRNA 31 e) large subunit of the ribosome

Question 39

What catalyzes peptide bond formation between amino acids at the P and A sites? What does this result in?

Answer 39

1. Peptidyl transferase (part of the ribosome, an rRNA ribozyme) 2. elongating the polypeptide and transferring it to the tRNA at the A site

Question 40

What do all organisms use to bind a stop codon in the A site?

Answer 40

protein release factors (RF)

Question 41

__________: RF1 → UAG, UAA; RF2 → UAA, UGA; RF3 recycles RF1 Archaea: aRF1 → all _____ codons Eukarya: ____ → all stop codons; extra release factor recycles eRF1

Answer 41

bacteria stop eRF1

Question 42

Which of the following is not a stop codon? a) UGA b) UAG c) AUG d) UAA e) all of these are stop codons

Question 43

protein sequence is ________ conserved across animals but, still significant variation in parts of amino acid sequence?

Answer 43

highly

Question 44

what gene is a critical gene in early development of the eye and brain?

Answer 44

The pax6 gene