Question 1

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

Accepted Answer

Both CAT and CAA encode the amino acid valine,so the final protein will not be affected.

Question 2

A β-pleated sheet is a type of

Accepted Answer

A) primary structure found in a protein. 
B) secondary structure found in a protein. 
C) tertiary structure found in a protein. 
D) quaternary structure found in a protein. 
E) heme structure found in a protein. 
A) primary structure found in a protein. 
B) secondary structure found in a protein. 
C) tertiary structure found in a protein. 
D) quaternary structure found in a protein. 
E) heme structure found in a protein. B

Question 3

Which of the following statements is not true of proteins destined for the ER?

Accepted Answer

A) They have a signal sequence. 
B) The signal sequence for the ER consists of 15-30 amino acids. 
C) The proteins are modified with carbohydrates in the ER. 
D) The signal sequence is subsequently removed from the mature protein. 
E) The SRP binds to the protein and prevents entry into the ER until translation is completed. 
A) They have a signal sequence. 
B) The signal sequence for the ER consists of 15-30 amino acids. 
C) The proteins are modified with carbohydrates in the ER. 
D) The signal sequence is subsequently removed from the mature protein. 
E) The SRP binds to the protein and prevents entry into the ER until translation is completed. E

Question 4

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

Question 5

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 6

During translation,mRNA codons bind to complementary tRNA anticodons.

Accepted Answer

A) True 
 B)False

Question 7

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

Accepted Answer

A) Tryptophan (no change) 
B) Serine 
C) Arginine 
D) Threonine 
E) None (a stop codon will halt translation) 
A) Tryptophan (no change) 
B) Serine 
C) Arginine 
D) Threonine 
E) None (a stop codon will halt translation)

Question 8

What are the two sulfur-containing amino acids that contribute to a protein's tertiary structure?

Accepted Answer

Cysteine a

Question 9

Of the codons AAU,AUG,UAA,and UAU,which is considered a nonsense codon? What does this mean?

Accepted Answer

UAA is a nonsense,or stop,codo

Question 10

Describe and differentiate among the primary,secondary,and tertiary structures of a protein.To which kinds of interactions can each of these stages be ascribed?

Accepted Answer

Primary protein structure refers to the

Question 11

The genetic code is comma-free,nonoverlapping,and almost universal.

Accepted Answer

A) True 
 B)False

Question 12

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 13

Protein synthesis begins when ribosomes bind to the UGA codon.

Accepted Answer

A) True 
 B)False

Question 14

What is the function of a ribosome?

Accepted Answer

A) To direct transcription 
B) To attach amino acids to the appropriate tRNAs 
C) To unwind the double-stranded DNA helix to enable translation 
D) To hold mRNA and tRNAs in the correct positions to enable translation 
E) To make more mRNA 
A) To direct transcription 
B) To attach amino acids to the appropriate tRNAs 
C) To unwind the double-stranded DNA helix to enable translation 
D) To hold mRNA and tRNAs in the correct positions to enable translation 
E) To make more mRNA

Question 15

In the genetic code,both AAU and AAC code for asparagine.For this reason,the code is said to be

Accepted Answer

A) degenerate. 
B) nonspecific. 
C) universal. 
D) ambiguous. 
E) wobbly. 
A) degenerate. 
B) nonspecific. 
C) universal. 
D) ambiguous. 
E) wobbly.

Question 16

The concept that a set of three nucleotides specifies a particular amino acid provides the basis for

Accepted Answer

A) the one-gene-one-enzyme hypothesis. 
B) the one-gene-one-polypeptide hypothesis. 
C) the genetic code. 
D) biochemical reactions among nucleic acids. 
E) All of these 
A) the one-gene-one-enzyme hypothesis. 
B) the one-gene-one-polypeptide hypothesis. 
C) the genetic code. 
D) biochemical reactions among nucleic acids. 
E) All of these

Question 17

What is the basic shape of a tRNA molecule?

Accepted Answer

A) A three-dimensional cloverleaf 
B) A straight strand 
C) A right-handed helix 
D) A globular ball 
E) A β-pleated sheet 
A) A three-dimensional cloverleaf 
B) A straight strand 
C) A right-handed helix 
D) A globular ball 
E) A β-pleated sheet

Question 18

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

Accepted Answer

A) True 
 B)False

Question 19

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

Accepted Answer

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

Question 20

Molecular chaperones

Accepted Answer

A) help guide proteins from the nucleus to the cytoplasm. 
B) help guide proteins from the cytoplasm to the endoplasmic reticulum. 
C) help fold proteins properly. 
D) are proteins with structural function. 
E) are proteins with enzymatic function. 
A) help guide proteins from the nucleus to the cytoplasm. 
B) help guide proteins from the cytoplasm to the endoplasmic reticulum. 
C) help fold proteins properly. 
D) are proteins with structural function. 
E) are proteins with enzymatic function.

Exam 6: Gene Expression: Translation

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

A β-pleated sheet is a type of

Which of the following statements is not true of proteins destined for the ER?

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?

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?

During translation,mRNA codons bind to complementary tRNA anticodons.

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

What are the two sulfur-containing amino acids that contribute to a protein's tertiary structure?

Of the codons AAU,AUG,UAA,and UAU,which is considered a nonsense codon? What does this mean?

Describe and differentiate among the primary,secondary,and tertiary structures of a protein.To which kinds of interactions can each of these stages be ascribed?

The genetic code is comma-free,nonoverlapping,and almost universal.

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.

Protein synthesis begins when ribosomes bind to the UGA codon.

What is the function of a ribosome?

In the genetic code,both AAU and AAC code for asparagine.For this reason,the code is said to be

The concept that a set of three nucleotides specifies a particular amino acid provides the basis for

What is the basic shape of a tRNA molecule?

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

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

Molecular chaperones

Genetics: An Introduction

DNA: The Genetic Material

DNA Replication

Gene Function

Gene Expression: Transcription

Dna Mutation, DNA Repair, and Transposable Elements

Genomics: The Mapping and Sequencing of Genomes

Functional and Comparative Genomics

Recombinant DNA Technology

Mendelian Genetics

Chromosomal Basis of Inheritance

Extensions of and Deviations From Mendelian Genetic Principles

Genetic Mapping in Eukaryotes

Genetics of Bacteria and Bacteriophages

Variations in Chromosome Structure and Number

Regulation of Gene Expression in Bacteria and Bacteriophages

Regulation of Gene Expression in Eukaryotes

Genetic Analysis of Development

Genetics of Cancer

Population Genetics

Quantitative Genetics

Molecular Evolution

Filters