Question 1

Ribozymes in the large ribosomal subunit catalyze peptidyl transferase activity during elongation. What is the immediate result?

Accepted Answer

A)  The tRNA in the P site falls off the ribosome. 
B)  The ribosome shifts by one codon toward the 3' end of the mRNA. 
C)  A new charged tRNA moves into the A site. 
D)  The bond is broken between the tRNA at the P site and its amino acid, and a peptide bond is formed between this amino acid and the one attached to the tRNA in the A site. 
E)  The elongation factor EF-Tu is recycled. 
A)  The tRNA in the P site falls off the ribosome. 
B)  The ribosome shifts by one codon toward the 3' end of the mRNA. 
C)  A new charged tRNA moves into the A site. 
D)  The bond is broken between the tRNA at the P site and its amino acid, and a peptide bond is formed between this amino acid and the one attached to the tRNA in the A site. 
E)  The elongation factor EF-Tu is recycled. D

Question 2

In eukaryotes, the AUG initiation codon is located in the ________ sequence.

Accepted Answer

A)  Shine-Dalgarno 
B)  Pribnow 
C)  Kozak 
D)  Goldberg-Hogness 
E)  Khorana 
A)  Shine-Dalgarno 
B)  Pribnow 
C)  Kozak 
D)  Goldberg-Hogness 
E)  Khorana C

Question 3

Why is it that a carrot plant can express a bacterial gene?

Accepted Answer

A)  Because the bacterial gene hijacks the carrot's cellular machinery 
B)  Because of the degeneracy of the genetic code 
C)  Because the genetic code is the same in both organisms 
D)  Because of the wobble phenomenon 
E)  A carrot cannot express a bacterial gene. 
A)  Because the bacterial gene hijacks the carrot's cellular machinery 
B)  Because of the degeneracy of the genetic code 
C)  Because the genetic code is the same in both organisms 
D)  Because of the wobble phenomenon 
E)  A carrot cannot express a bacterial gene. C

Question 4

How many naturally occurring amino acids are used by ribosomes to construct proteins?

Accepted Answer

A)  64 
B)  10 
C)  20 
D)  46 
E)  3 
A)  64 
B)  10 
C)  20 
D)  46 
E)  3

Question 5

What is the role of tRNA in translation?

Accepted Answer

A)  It catalyzes peptidyl transferase activity. 
B)  It binds to an mRNA codon and carries the corresponding amino acid. 
C)  It helps fold up the finished polypeptide chain. 
D)  It couples an amino acid with aminoacyl-tRNA synthetase. 
E)  It brings together two subunits of a ribosome. 
A)  It catalyzes peptidyl transferase activity. 
B)  It binds to an mRNA codon and carries the corresponding amino acid. 
C)  It helps fold up the finished polypeptide chain. 
D)  It couples an amino acid with aminoacyl-tRNA synthetase. 
E)  It brings together two subunits of a ribosome.

Question 6

With absolutely no exception, all organisms utilize the same genetic code for the production of proteins.

Accepted Answer

A) True 
 B)False

Question 7

What signals the termination of translation?

Accepted Answer

A)  The ribosome reaches a start codon. 
B)  The ribosome runs out of charged tRNAs. 
C)  The ribosome reaches a stop codon. 
D)  The ribosome reaches the end of the mRNA. 
E)  The polypeptide chain folds into a protein. 
A)  The ribosome reaches a start codon. 
B)  The ribosome runs out of charged tRNAs. 
C)  The ribosome reaches a stop codon. 
D)  The ribosome reaches the end of the mRNA. 
E)  The polypeptide chain folds into a protein.

Question 8

A mutation causes a G to be inserted after the first base of the codon for tryptophan. How will this affect the growing polypeptide chain?

Accepted Answer

A)  It will not be affected. 
B)  The reading frame will be shifted to the left, and the wrong amino acids will be added from this point on. 
C)  There will be a single amino acid substitution. 
D)  Elongation will stop prematurely. 
E)  None of the above 
A)  It will not be affected. 
B)  The reading frame will be shifted to the left, and the wrong amino acids will be added from this point on. 
C)  There will be a single amino acid substitution. 
D)  Elongation will stop prematurely. 
E)  None of the above

Question 9

What is the wobble hypothesis, and what implications does it have for base-pairing rules and selective pressure on codons?

Accepted Answer

The wobble hypothesis refers to the dege

Question 10

Would a two-letter code with four different nucleotides be sufficient to encode the 20 amino acids found in cells? Why or why not? What does the three-letter code imply about the nature of the genetic code?

Accepted Answer

A two-letter code would only encode 16 (

Question 11

Which of the following statements is correct?

Accepted Answer

A)  For every amino acid, there is one codon. 
B)  For every codon, there is one amino acid. 
C)  A codon may signify more than one amino acid. 
D)  All of these are correct. 
E)  None of these are correct. 
A)  For every amino acid, there is one codon. 
B)  For every codon, there is one amino acid. 
C)  A codon may signify more than one amino acid. 
D)  All of these are correct. 
E)  None of these are correct.

Question 12

Protein synthesis begins when ribosomes bind to the UGA codon.

Accepted Answer

A) True 
 B)False

Question 13

Where does translation take place?

Accepted Answer

A)  In the centriole 
B)  In the nucleus 
C)  Anywhere in the cell 
D)  In the nucleolus 
E)  In the cytoplasm 
A)  In the centriole 
B)  In the nucleus 
C)  Anywhere in the cell 
D)  In the nucleolus 
E)  In the cytoplasm

Question 14

Part of a DNA gene sequence reads CAT. If a mutation occurs changing the T to A, will the final protein be affected?

Accepted Answer

Both CAT and CAA enc

Question 15

Describe the basic structure of an amino acid.

Accepted Answer

The structure consists of a ce

Question 16

There are 64 sense codons in the genetic code and 61 different types of tRNA molecules.

Accepted Answer

A) True 
 B)False

Question 17

Why is methionine the first amino acid to be added to every polypeptide chain?

Accepted Answer

Because the start codon, AUG,

Question 18

In the genetic code, when the first two nucleotides of a triplet are identical and the third letter is U or C, the codon always codes for the same amino acid.

Accepted Answer

A) True 
 B)False

Question 19

How did von Ehrenstein et al. demonstrate that the specificity of codon recognition lies in the tRNA molecule, not in the amino acid it carries?

Accepted Answer

In vitro, they chemically converted the

Question 20

In a gene sequence, the DNA codon for tryptophan experiences a mutation at the first base position, changing it to T. What will be the resulting amino acid?

Accepted Answer

A)  Arginine 
B)  Tryptophan (no change) 
C)  Threonine 
D)  Serine 
E)  A stop codon will halt translation. 
A)  Arginine 
B)  Tryptophan (no change) 
C)  Threonine 
D)  Serine 
E)  A stop codon will halt translation.

Exam 13: Regulation of Gene Expression in Eukaryotes

Ribozymes in the large ribosomal subunit catalyze peptidyl transferase activity during elongation. What is the immediate result?

In eukaryotes, the AUG initiation codon is located in the ________ sequence.

Why is it that a carrot plant can express a bacterial gene?

How many naturally occurring amino acids are used by ribosomes to construct proteins?

What is the role of tRNA in translation?

With absolutely no exception, all organisms utilize the same genetic code for the production of proteins.

What signals the termination of translation?

A mutation causes a G to be inserted after the first base of the codon for tryptophan. How will this affect the growing polypeptide chain?

What is the wobble hypothesis, and what implications does it have for base-pairing rules and selective pressure on codons?

Would a two-letter code with four different nucleotides be sufficient to encode the 20 amino acids found in cells? Why or why not? What does the three-letter code imply about the nature of the genetic code?

Which of the following statements is correct?

Protein synthesis begins when ribosomes bind to the UGA codon.

Where does translation take place?

Part of a DNA gene sequence reads CAT. If a mutation occurs changing the T to A, will the final protein be affected?

Describe the basic structure of an amino acid.

There are 64 sense codons in the genetic code and 61 different types of tRNA molecules.

Why is methionine the first amino acid to be added to every polypeptide chain?

In the genetic code, when the first two nucleotides of a triplet are identical and the third letter is U or C, the codon always codes for the same amino acid.

How did von Ehrenstein et al. demonstrate that the specificity of codon recognition lies in the tRNA molecule, not in the amino acid it carries?

In a gene sequence, the DNA codon for tryptophan experiences a mutation at the first base position, changing it to T. What will be the resulting amino acid?

Genetics of Bacteria and Bacteriophages

Variations in Chromosome Structure and Number

Advanced Gene Mapping in Eukaryotes

Gene Mapping in Eukaryotes

Quantitative Genetics

Extensions of Mendelian Genetic Principles

Chromosomal Basis of Inheritance

Molecular Evolution

Population Genetics

Non-Mendelian Inheritance

Genetics of Cancer

Genetic Analysis of Development

Mendelian Genetics

Regulation of Gene Expression in Bacteria and Bacteriophages

Genomics

Applications of Recombinant DNA Technology

Recombinant DNA Technology

DNA Mutation, DNA Repair, and Transposable Elements

Gene Expression: Translation

Gene Expression: Transcription

Gene Control of Proteins

DNA Replication

DNA: The Genetic Material

Genetics: an Introduction

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