Deck 12: Translation And The Genetic Code

Question 1

Which of the following is a secondary structure often observed in proteins?

A) a helix
B) b sheet
C) s subunit
D) a helix and b sheet
E) All of these

Answer 1

D

Question 2

All of the amino acids,except Proline,contain:

A) A free amine group
B) A free carboxyl group
C) A free R group
D) A free amine group and a free carboxyl group
E) A free carboxyl group and a free R group

Answer 2

D

Question 3

Amino acids differ from one another by the _________ that are present.

A) Amino group
B) Carboxyl group
C) R group
D) R plasmid
E) Core group

Answer 3

C

Question 4

Proteins that help nascent polypeptides form the correct three dimensional structure are known as:

A) Guide proteins
B) Chaperone proteins
C) Folding proteins
D) Tertiary proteins
E) Scaffold proteins

Question 5

When a mRNA molecule is simultaneously translated by several ribosomes,the result is the formation of a/an:

A) Polysome
B) Polypeptie
C) Ribosome
D) Charged tRNA
E) None of these

Question 6

In which part of a eukaryotic cell does translation take place?

A) Nucleus
B) Ribosomes
C) Lysosome
D) Nucleolus
E) Smooth ER

Question 7

A compound composed of two or more amino acids is known as a/an:

A) Peptide
B) Amino
C) Nucleotide
D) Peptide and Amino
E) All of these

Question 8

How many different amino acids can be used in the composition of proteins?

A) 5
B) 10
C) 15
D) 20
E) 30

Question 9

Which of the following non-covalent bonds is not involved in the tertiary structure formation of proteins?

A) Ionic bonds
B) Hydrogen bonds
C) Disulfide bridges
D) Hydrophobic interactions
E) Van der Waal interactions

Question 10

Which of the following is a type of R group?

A) Hydrophobic
B) Hydrophilic
C) Acidic
D) Basic
E) All of these

Question 11

Of the 64 possible nucleotide codon triplets,how many specify polypeptide chain termination?

A) 61
B) 1
C) 2
D) 3
E) 64

Question 12

Which of the following statements is correct about RNA involvement in translation?

A) Aminoacyl-tRNA synthetases are responsible for attaching amino acids to the appropriate tRNAs.
B) The nucleolus is responsible for the synthesis of tRNAs catalyzed by RNA Pol II.
C) Eukaryotes, because of the complexity of their genome, are able to maintain multiple copies of rRNA genes. In contrast, the highly simplified genome of E. coli maintains a single copy.
D) The adapter molecule of protein synthesis, the rRNA, recognizes the anticodons of the mRNA molecule to direct protein synthesis.
E) None of these is correct.

Question 13

The process by which the genetic information stored in mRNA nucleotide sequences is used to specify the amino acid sequences in polypeptide gene products is known as:

A) Replication
B) Transcription
C) Translation
D) Transcription and Translation
E) None of these

Question 14

Amino acids in polypeptides are joined by what type of bond?

A) Hydrogen
B) Peptide
C) Covalent
D) Ionic
E) Weak

Question 15

Which set of enzymes is responsible for attaching the correct amino acid to an appropriate tRNA molecule during the charging process?

A) RNA gyrases
B) RNA polymerases
C) Amino-acyl transacetylases
D) Aminoacyl tRNA synthetases
E) All of these

Question 16

Which of the following statements about protein structure is correct?

A) The primary structure of a protein does not dictate the final shape of the protein.
B) Two common types of secondary structure are a helices and b sheets, both of which are held in place via hydrogen bonds.
C) Tertiary protein structure is maintained primarily by covalent disulfide bridges.
D) All peptides exhibit four levels of structural organization: primary, secondary, tertiary, and quaternary.
E) Ionic bonds in tertiary structure maintain a strong attraction between amino acids in the interior of living cells.

Question 17

Which of the following statements is not correct about amino acids and proteins?

A) There are 20 different amino acids
B) Structures of the amino acids can be modified
C) Side chains are designated R-groups, which can belong to one of four classes: hydrophobic, hydrophilic, acidic, and basic
D) Peptide bonds are formed between the amino groups of two amino acids
E) All of these are correct

Question 18

The association of two or more polypeptides in a multimeric protein is know as the:

A) Primary structure
B) Secondary structure
C) Tertiary structure
D) Quaternary structure
E) None of these

Question 19

The amino acid sequence of a polypeptide is the:

A) Primary structure
B) Secondary structure
C) Tertiary structure
D) Quaternary structure
E) None of these

Question 20

Which type(s)of RNA molecules are involved in the translation process?

A) mRNA
B) tRNA
C) rRNA
D) mRNA and tRNA
E) All of these

Question 21

What type of bond occurs between the nucleotide bases in the codon and the anticodon?

A) Ionic
B) Covalent
C) Hydrogen
D) Disulfide bridges
E) Peptide

Question 22

Which of the following is a difference in the process of initiation of translation between prokaryotes and eukaryotes? 1.The amino group of the methionine on the initiator tRNA is not formylated in eukaryotes as it is in prokaryotes.
2)The initiation complex forms at the 5¢ terminus of the mRNA,not at the Shine-Dalgarno/AUG translation start site as in prokaryotes.
3)The process takes place at the ribosome in prokaryotes but not in eukaryotes.

A) 1
B) 2
C) 3
D) 1 and 3
E) All of these

Question 23

Eukaryotic initiation of translation is similar to prokaryotes in which of the following ways?

A) There is a formyl group on the initiation methionine
B) Initiation complex forms at the Shine-Dalgarno/AUG translation start site
C) After binding, the ribosome scans the mRNA and begins translation at the first available AUG
D) The initiator methionyl-tRNA interacts with a soluble initiation factor and enters the P-site directly
E) All of these

Question 24

Which of the following is not directly required for chain elongation during translation?

A) Ef-Tu
B) A site on the ribosome
C) GTP
D) IF2
E) All of these are required

Question 25

The genetic code is:

A) Composed of triplet codons
B) Non-overlapping
C) Degenerate
D) Universal
E) All of these

Question 26

Which of the following is a chain termination codon?

A) UAA
B) UAG
C) UGA
D) UAA and UAG
E) All of these

Question 27

Which of the following is a tRNA binding site on a ribosome?

A) P
B) A
C) E
D) P and A
E) All of these

Question 28

Which of the following codons is most often recognized as the start codon for translation?

A) GUA
B) AUG
C) CUG
D) UUG
E) AAG

Question 29

Which of the following is an unusual nucleoside that is only found in tRNA?

A) Adenine
B) Inosine
C) Proline
D) Phenylalanine
E) Guanine

Question 30

Which of the following is the correct anti-codon sequence that corresponds with the codon sequence AUG?

A) AUG
B) GUA
C) TAC
D) UAC
E) CAU

Question 31

During translocation the peptidyl-tRNA present in the A site of the ribosome is translocated to the P site,and the uncharged tRNA in the P site is translocated to the E site,as the ribosome moves three nucleotides toward the 3¢ end of the mRNA molecule.Which of the following soluble factors is required for this process to occur?

A) IF-1
B) EF-Tu
C) EF-G
D) IF-2
E) IF-3

Question 32

The reaction in which the growing chain from the tRNA in the P site covalently joins the chain to the tRNA in the A site is catalyzed by which of the following enzymes?

A) Gyrase
B) Topoisomerase
C) Peptidyl transferase
D) Aminoacyl - tRNA synthetase
E) Ligase

Question 33

Unusual nucleosides that are found in mature tRNA molecules are added during:

A) Transcription initiation
B) Transcription elongation
C) Transcription termination
D) Post transcriptional modification
E) It is not currently known when the unusual nucleosides are added

Question 34

Most amino acids are specified by two to four different codons.This means that the genetic code is:

A) Non-overlapping
B) Degenerate
C) Ordered
D) Non-degenerate
E) Universal

Question 35

The initiation of translation with the 30S ribosomal subunit in E.coli does not involve which of the following:

A) tRNAf???
B) Initiation factors IF-1, IF-2, and IF-3
C) ATP
D) GTP
E) mRNA with the appropriate Shine-Dalgarno sequence complementary to a sequence found within the 16S rRNA

Question 36

With few exceptions,all 64 codons have the same meaning in all organisms.This means that the genetic code is:

A) Non-overlapping
B) Degenerate
C) Ordered
D) Non-degenerate
E) Universal

Question 37

In the process of coupling tRNAs to amino acids,which of the following statements is INCORRECT?

A) Amino acids attach to the 3' end of tRNAs.
B) Prior to attachment between tRNA and amino acid, the amino acid becomes linked to AMP by aminoacyl-tRNA synthetase.
C) The amino acid-AMP linkage is broken to attach the amino acid to the tRNA and release AMP by aminoacyl-tRNA synthetase.
D) Aminoacyl-tRNA synthetase is responsible for matching the correct tRNA with the appropriate amino acid.
E) None of these.

Question 38

The initiation complex moves in which direction along the mRNA molecule?

A) 5' ® 3'
B) 3' ® 5'
C) 1'® 4'
D) 5' ® 3' and 3' ® 5'
E) None of these

Question 39

Polypeptide chain elongation and termination of translation differ in prokaryotes and eukaryotes in which of the following ways?

A) Binding of the aminoacyl-tRNA to the A-site
B) Number of release factors
C) Transfer of the growing peptide from the tRNA in the P-site to the tRNA in the A-site
D) Translocation requirement of GTP hydrolysis
E) Translocation of the ribosome along the mRNA to position the next codon in the A-site

Question 40

Which of the following is not a true statement about ribosomes?

A) They are structured into large and small subunits
B) They are comprised of RNA and protein
C) The ribosomes in prokaryotes are typically larger than those found in eukaryotes
D) The ribosome subunits associate during the initiation of translation
E) All of these are false statements

Question 41

Briefly summarize the roles that each of the components play in the process of translation.

Question 42

If a tRNA?l? alters its anticodon from 3'-AUC-5' to the sequence to 3'-AUU-5',which of the following mutations can be suppressed?

A) Missense
B) Missense only if alanine does not adversely affect protein structure
C) Silent
D) Nonsense (only the 5'-UAA-3' codon)
E) None of these

Question 43

Which position on the anticodon is the wobble position?

A) 5' end
B) 3' end
C) Middle of the Anticodon
D) 5' end or 3' end
E) Any position can be the wobble position

Question 44

Explain how chain termination occurs during translation,including the differences between chain termination in prokaryotes and eukaryotes.

Question 45

Summarize the steps in chain elongation during translation.

Question 46

Explain,in detail,how translation is initiated in E.coli.

Question 47

Based upon the Wobble hypothesis,when inosine is present at the 5' end of the anitocodon,with which of the following bases will it base pair?

A) Adenine
B) Uracil
C) Cytosine
D) Adenine and Uracil
E) All of these

Question 48

The hydrogen bonding between the bases in the anticodons of tRNAs and the corresponding codons of mRNAs follows strict base-pairing rules only for the first two bases,while the base-pairing for the third base of the codon is less stringent.This is known as the:

A) Crick hypothesis
B) tRNA hypothesis
C) Wobble hypothesis
D) Central Dogma
E) None of these

Question 49

Explain the Wobble hypothesis and discuss the predictions based upon this hypothesis that have proven true.

Question 50

Which of the following is a type of mutation that can cause altered codon recognition?

A) Suppressor mutations
B) Nonsense mutations
C) Missense mutations
D) Suppressor mutations and Nonsense mutations
E) All of these