Deck 11: From DNA to Protein- Translation

Question 1

Which of the following amino acid is encoded by the LARGEST number of codons?

A)ARG
B)MET
C)PHE
D)VAL
E)GLY

Answer 1

A

Question 2

How many different amino acid sequences can be encoded by the sequence of 9 nucleotides long (ignore the possibility of stop codons)?

A)9
B)180
C)900
D)4000
E)8000

Answer 2

E

Question 3

Which of the following statements about translation is CORRECT?

A)A special tRNA that does not have an attached amino acid binds to stop codons to terminate translation.
B)The first three bases at the 5'end of an mRNA are the AUG at which translation begins.
C)The codon for methionine appears only at the beginning of the mRNA for a protein, not in the middle or in the end.
D)In eukaryotes, the 5' cap and the 3' poly(A)tail are involved in translation initiation.
E)Ribosomes move along an mRNA in the 3'to 5' direction.

Answer 3

In eukaryotes, the 5' cap and the 3' poly(A)tail are involved in translation initiation.

Question 4

If the bottom strand of the DNA serves as the template, the amino acid sequence of the protein produced from the RNA would be:

A)MET-LEU-SER.
B)ARG-VAL-HIS.
C)THR-ILE-PHE.
D)PRO-GLY-TRP.
E)LYS-VAL-HIS.

Question 5

How many reading frames are encoded by the sense nucleotide strand?

A)One
B)Two
C)Three
D)Six
E)Ten

Question 6

If the bottom strand of the DNA from the diagram above serves as the template strand, the RNA sequence, left to right 5' to 3', is:

A)AUAGGCAGU.
B)UCCCAGGUG.
C)CACCUGGGA.
D)AGGGUCCAC.
E)GACAUUAGA.

Question 7

Which of the following amino acids is NOT encoded by the synonymous codons?

A)MET
B)VAL
C)GLY
D)ARG
E)SER

Question 8

Which of the following is NOT required during the process of tRNA charging?

A)Amino acid
B)tRNA
C)GTP
D)ATP
E)Aminoacyl-tRNA synthetase

Question 9

During initiation of translation:

A)the initiator tRNAmet binds to the A site of a ribosome.
B)specific rRNA base pairs with a sequence in mRNA to position a ribosome at the start codon.
C)IF-3 must be recruited to the 30S ribosome in order for the 70S initiation complex to assemble.
D)there is no energy expenditure as the tRNA binding to mRNA is via complementary base pairing.
E)both 70S and 30S ribosome subunits must simultaneously recognize an mRNA to bind.

Question 10

The amino acids in proteins are joined together by _____ bonds.

A)peptide
B)hydrogen
C)ionic
D)acetyl
E)oxygen

Question 11

Which amino acid is encoded by four synonymous codons?

A)MET
B)VAL
C)PHE
D)CYS
E)ILE

Question 12

If the bottom strand of the DNA is the template, the tRNA anticodon sequence, left to right 5' to 3', for the first RNA codon is:

A)GGA.
B)AUG.
C)CAC.
D)UCC.
E)CCU.

Question 13

Which of the following is observed in prokaryotes but not in eukaryotes?

A)UGG is an example of a stop codon only found in prokaryotes.
B)An mRNA can be translated by only one ribosome at a time in prokaryotes.
C)The 5' end of a prokaryotic mRNA can be translated while the 3'end is still being transcribed.
D)Translation does not require any protein factors in prokaryotes.
E)In prokaryotes, ribosomes move along an mRNA in the 3' to 5' direction.

Question 14

Which amino acid is coded by the stop codons in most organisms?

A)MET
B)PRO
C)TRP
D)CYS
E)No amino acid is coded.

Question 15

An anticodon would be found on which of these molecules?

A)Amino acid
B)mRNA
C)DNA
D)tRNA
E)rRNA

Question 16

If the sequence contains 4 nucleotides (4-nu long), how many different nucleotide sequences can be encoded by it?

A)16
B)24
C)64
D)128
E)256

Question 17

For a sequence of nucleotides, how many reading frames are possible?

A)One
B)Two
C)Three
D)Six
E)Ten

Question 18

Process 2 represents:

A)replication.
B)transcription.
C)translation.
D)RNA processing.
E)RNA interference.

Question 19

Which codon from the list below, codes a different amino acid than the others?

A)CUU
B)CUC
C)UUA
D)UUU
E)CUA

Question 20

Which of the following statements describes the "wobble" rules CORRECTLY?

A)There is a flexible pairing between tRNA and amino acid as there are more tRNAs than the number of amino acids.
B)The number of the genetic code exceeds the number of amino acids available in the cell.
C)There are multiple tRNAs that may bind to the same amino acids.
D)There are multiple codons that may code for the same amino acids.
E)The third base pairing between the tRNA and mRNA is relaxed.

Question 21

A bacterial protein is encoded by the following mRNA sequence: 5'-AUGGUGCUCAUGCCCTAA-3'
The second methionine codon (AUG)in this mRNA sequence will:

A)serve as the initiation codon.
B)encode N-formylmethionine.
C)encode methionine that will eventually be removed.
D)encode unformylated methionine.
E)be skipped as the translation progresses.

Question 22

The genetic code is said to be "degenerate" because:

A)there are more codons than amino acids.
B)there are more amino acids than codons.
C)different organisms use different codons to encode the same amino acid.
D)some codons specify more than one amino acid.
E)there are more tRNAs than amino acids.

Question 23

There are _____ different codons, which encode 20 amino acids and three stop codons.

A)16
B)20
C)23
D)61
E)64

Question 24

A tRNA anticodon is 3'-GCU-5'.What amino acid does it carry?

A)Ala
B)Arg
C)Ser
D)Pro
E)Thr

Question 25

The amino acid sequence of a polypeptide is referred to as the _____ sequence of the polypeptide.

A)primary
B)secondary
C)tertiary
D)quaternary

Question 26

During initiation, the _____ subunit is the first part of the ribosome to associate with the mRNA.

A)small
B)large
C)intermediary
D)secondary
E)tertiary

Question 27

After the peptide bond forms, what will happen?

A)tRNA A will be carrying the polypeptide and it will shift to the P site.
B)tRNA A will be carrying the polypeptide and it will shift to the A site.
C)tRNA B will be carrying the polypeptide and it will shift to the P site.
D)tRNA B will be carrying the polypeptide and it will shift to the A site.
E)Ribosome disassembles to release the tRNAs and allow new tRNA to enter.

Question 28

An mRNA has the stop codon 5'UAA 3'.What tRNA anticodon will bind to it?

A)5' ATT 3'
B)5'AUC 3'
C)5'ACU 3'
D)5' UUA 3'
E)None

Question 29

The function of aminoacyl-tRNA synthetases is to:

A)transcribe tRNA genes.
B)match tRNA anticodons and mRNA codons at the ribosome.
C)attach appropriate amino acids to corresponding tRNAs.
D)form the peptide bond between amino acids at the ribosome.
E)synthesize and transport amino acids to the ribosomes.

Question 30

Codons that specify the same amino acid are said to be:

A)wobbly.
B)isoaccepting.
C)hypothetical.
D)synonymous.
E)anonymous.

Question 31

When codons that code for the same amino acid differ in their _____, a single tRNA might bind both of them through wobble base pairing.

A)5' base
B)middle base
C)3' base

Question 32

During elongation, an incoming charged tRNA enters at the _____ site of the ribosome.

A)peptidyl (P)
B)aminoacyl (A)
C)exit (E)
D)Shine-Dalgarno
E)Kozak

Question 33

What is the minimum number of different aminoacyl-tRNA synthetases required by a cell?

A)64, one for each codon
B)61, one for each sense codon
C)30, one for each different tRNA
D)50, one for each different tRNA
E)20, one for each amino acid

Question 34

To translate an mRNA requires two other types of RNA.These are:

A)tRNA and mRNA.
B)tRNA and miRNA.
C)tRNA and rRNA.
D)rRNA and siRNA.
E)snRNA and snoRNA.

Question 35

The next step in the translation of this mRNA will be the formation of a peptide bond between which two amino acids?

A)Amino acid 2 and amino acid 3
B)Amino acid 2 and amino acid 4
C)Amino acid 1 and amino acid 3
D)Amino acid 1 and amino acid 2
E)Amino acid 3 and amino acid 4

Question 36

Wobble base pairing will occur for which one of the following pair of codons?

A)AUG and AUA
B)UUU and UUC
C)CCC and AAA
D)UUU and UUG
E)UUU and UUC and UUU and UUG are both correct.

Question 37

An mRNA has the codon 5' UAC 3'.What tRNA anticodon will bind to it?

A)5'AUG 3'
B)5' GUA 3'
C)5' ATC 3'
D)5'CTA 3'
E)5' CAU 3'

Question 38

The genetic code is universal EXCEPT for:

A)prokaryotes, which use a different genetic code than eukaryotes.
B)a few mitochondrial genes, which substitute one sense codon for another.
C)viruses, which use an entirely different genetic code.
D)archaebacteria, which have their own genetic code.
E)animal species whose cells are more advanced and complex.

Question 39

What level of protein structure is expressed in the following: VAL-LYS-GLY?

A)Primary
B)Secondary
C)Tertiary
D)Quaternary

Question 40

Where does variation exist in the general structure of the amino acid?

A)Amino group
B)Carboxyl group
C)R group
D)Central carbon
E)Hydrogen

Question 41

An auxotrophic E.coli strain requires adenine to grow because of a mutation in a gene for an adenine synthesis enzyme.The following shows part of the wild type and mutant alleles of the gene, including the start codon.The bottom strand is the template for transcription. How does this mutation change the mRNA, and how does it affect the enzyme?

Question 42

Which amino acids are encoded if the reading frame is as shown below, starting from the correct end?
5' ...GGAGCUCGUUGUAUU...3'

Question 43

Describe the events in prokaryotic translation elongation.

Question 44

Can a human gene sequence be transcribed and translated inside an E.coli cell (assume it has a functional promoter sequence)?

A)It can be only translated, not transcribed.
B)No, it cannot be transcribed and translated.
C)Yes, it can be transcribed and translated.
D)It can be only transcribed, not translated.
E)E)coli cells generally lack ribosomes.

Question 45

List three differences between prokaryotic and eukaryotic translation.

Question 46

On polyribosomes, the direction of mRNA transcription is:

A)5'-to-3'.
B)3'-to-5'.
C)both 5'-to-3' and 3'-to-5' directions.
D)each molecule alternates between 5'-to-3'and 3'-to-5F' directions.
E)always already translated polyribosomes.

Question 47

What would be the effect on the below amino acid sequence if the sequence were changed to 5'GGAGACUCGUUGUAUU 3'? Explain why the amino acid sequence changes.
5' ...GGAGCUCGUUGUAUU...3'

Question 48

Describe the events in prokaryotic translation initiation.

Question 49

A yeast strain was exposed to a chemical mutagen.As expected, exposure to the mutagen resulted in DNA sequence change in an essential gene you examined.Yet, this mutation did not result in any lethal phenotype.How could you explain this apparent discrepancy?

Question 50

This DNA sequence represents an open reading frame (ORF)of a transcriptional unit.Transcribe and then translate this gene in the spaces provided below.
5' ATGGGAGCTCGTTGTATTTGA 3'
3' TACCCTCGAGCAACATAAACT 5'

Question 51

Compute how many (different)nucleotide sequences can encode the following tri-peptide, VAL-GLY-ARG?

A)14
B)24
C)48
D)64
E)96

Question 52

List the codon, anticodon, and DNA code for the amino acid TRP.

Question 53

Which of the following codons is often used as an initiation codon?

A)UUU
B)UUA
C)AUU
D)AUG
E)AUC

Question 54

Although the genetic code is nearly universal, some variations do exist.In vertebrate mitochondria, UGA codes for Trp (instead of termination), AUA codes for Met (instead of Ile), and AGA and AGG are stop codons (instead of coding for Arg).Translate the following coding strand DNA sequences using both the standard code and the vertebrate mitochondrial code.
a.5' ATGGCCATAAGATGA 3'
b.5' ATGGGGGATCGCTAA 3'
c.5' ATGTGATGGCATCTTATAAATTGATAA 3'

Question 55

The genetic code uses three bases to encode one amino acid.Why can't the code use only two bases to encode each amino acid?

Question 56

What was Beadle and Tatum's definition of a gene? Give a modern definition and explain how it differs from that of Beadle and Tatum.

Question 57

Is the below sequence RNA or DNA? How can you tell?
5' ...GGAGCUCGUUGUAUU...3'

Question 58

During the elongation step of translation, ribosome translocates so that a specific codon of mRNA effectively transfers between _____ sites.

A)P and E
B)P and A
C)A and P
D)A and E
E)E and P