Question 1

What does it mean when we say the genetic code is redundant?

Accepted Answer

A)  A single codon can specify the addition of more than one amino acid. 
B)  The genetic code is different for different domains of organisms. 
C)  The genetic code is universal (the same for all organisms). 
D)  More than one codon can specify the addition of the same amino acid. 
A)  A single codon can specify the addition of more than one amino acid. 
B)  The genetic code is different for different domains of organisms. 
C)  The genetic code is universal (the same for all organisms). 
D)  More than one codon can specify the addition of the same amino acid. D

Question 2

Which one of the following is TRUE? A codon ________.

Accepted Answer

A)  consists of four nucleotides 
B)  can code for up to four different amino acids 
C)  extends from one end of a tRNA molecule 
D)  is the basic unit of the genetic code 
A)  consists of four nucleotides 
B)  can code for up to four different amino acids 
C)  extends from one end of a tRNA molecule 
D)  is the basic unit of the genetic code D

Question 3

The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?

Accepted Answer

A)  A gene from an organism can theoretically be expressed by any other organism. 
B)  All organisms have experienced convergent evolution. 
C)  DNA was the first genetic material. 
D)  The same codons in different organisms translate into different amino acids. 
E)  Different organisms have different types of amino acids. 
A)  A gene from an organism can theoretically be expressed by any other organism. 
B)  All organisms have experienced convergent evolution. 
C)  DNA was the first genetic material. 
D)  The same codons in different organisms translate into different amino acids. 
E)  Different organisms have different types of amino acids. A

Question 4

The following question(s) refer to this table of codons.  
-What amino acid sequence will be generated, based on the following mRNA codon sequence?
5' AUG-UCU-UCG-UUA-UCC-UUG 3'

Accepted Answer

A)  met-arg-glu-arg-glu-arg 
B)  met-glu-arg-arg-glu-leu 
C)  met-ser-leu-ser-leu-ser 
D)  met-ser-ser-leu-ser-leu 
E)  met-leu-phe-arg-glu-glu 
A)  met-arg-glu-arg-glu-arg 
B)  met-glu-arg-arg-glu-leu 
C)  met-ser-leu-ser-leu-ser 
D)  met-ser-ser-leu-ser-leu 
E)  met-leu-phe-arg-glu-glu

Question 5

A frameshift mutation could result from ________.

Accepted Answer

A)  a base insertion only 
B)  a base deletion only 
C)  a base substitution only 
D)  deletion of three consecutive bases 
E)  either an insertion or a deletion of a base 
A)  a base insertion only 
B)  a base deletion only 
C)  a base substitution only 
D)  deletion of three consecutive bases 
E)  either an insertion or a deletion of a base

Question 6

Which of the following DNA mutations is most likely to damage the protein it specifies?

Accepted Answer

A)  a base-pair deletion 
B)  an addition of three nucleotides 
C)  a substitution in the last base of a codon 
D)  a codon deletion 
A)  a base-pair deletion 
B)  an addition of three nucleotides 
C)  a substitution in the last base of a codon 
D)  a codon deletion

Question 7

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in ________.

Accepted Answer

A)  a base-pair substitution 
B)  a nucleotide mismatch 
C)  a frameshift mutation 
D)  a polypeptide missing an amino acid 
E)  a nonsense mutation 
A)  a base-pair substitution 
B)  a nucleotide mismatch 
C)  a frameshift mutation 
D)  a polypeptide missing an amino acid 
E)  a nonsense mutation

Question 8

Given the DNA template shown in the associated figure, which of the following bases would you find in a complementary RNA strand and where would they be synthesized?

Accepted Answer

A)  A-A-A-A-A; nucleus 
B)  U-U-U-U-U; nucleus 
C)  A-A-A-A-A; ribosome 
D)  U-U-U-U-U; ribosome 
A)  A-A-A-A-A; nucleus 
B)  U-U-U-U-U; nucleus 
C)  A-A-A-A-A; ribosome 
D)  U-U-U-U-U; ribosome

Question 9

Beadle and Tatum discovered that metabolic pathways are studied most effectively using which of the following techniques?

Accepted Answer

A)  using multiple gene mutations resulting in nonfunctional enzymes specific to a metabolic pathway 
B)  adding intermediates to a metabolic pathway 
C)  removing all intermediates of a metabolic pathway 
D)  using single gene mutations resulting in nonfunctional enzymes specific to a metabolic pathway 
A)  using multiple gene mutations resulting in nonfunctional enzymes specific to a metabolic pathway 
B)  adding intermediates to a metabolic pathway 
C)  removing all intermediates of a metabolic pathway 
D)  using single gene mutations resulting in nonfunctional enzymes specific to a metabolic pathway

Question 10

A nonsense mutation in a gene ________.

Accepted Answer

A)  changes an amino acid in the encoded protein 
B)  has no effect on the amino acid sequence of the encoded protein 
C)  introduces a premature stop codon into the mRNA 
D)  alters the reading frame of the mRNA 
E)  prevents introns from being excised 
A)  changes an amino acid in the encoded protein 
B)  has no effect on the amino acid sequence of the encoded protein 
C)  introduces a premature stop codon into the mRNA 
D)  alters the reading frame of the mRNA 
E)  prevents introns from being excised

Question 11

Refer to the metabolic pathway illustrated in the associated figure. If A, B, and C are all required for growth, a strain mutant for the gene encoding enzyme B would be able to grow on medium supplemented with ________.

Accepted Answer

A)  nutrient A only 
B)  nutrient B only 
C)  nutrient C only 
D)  nutrients A and C 
A)  nutrient A only 
B)  nutrient B only 
C)  nutrient C only 
D)  nutrients A and C

Question 12

Which of the following mutations is likely to cause the most dramatic phenotypic change?

Accepted Answer

A)  a duplication of all or most introns 
B)  a large inversion whose ends are each in the same region between genes 
C)  a nucleotide substitution in an exon coding for a transmembrane domain 
D)  a single nucleotide deletion in an exon coding for an active site 
E)  a frameshift mutation one codon away from the 3' end of the nontemplate strand 
A)  a duplication of all or most introns 
B)  a large inversion whose ends are each in the same region between genes 
C)  a nucleotide substitution in an exon coding for a transmembrane domain 
D)  a single nucleotide deletion in an exon coding for an active site 
E)  a frameshift mutation one codon away from the 3' end of the nontemplate strand

Question 13

All three domains (Bacteria, Archaea, and Eukarya) follow the same genetic code. Therefore, which of the following statements would most likely be correct?

Accepted Answer

A)  The genetic code evolved three times. 
B)  The genetic code evolved before DNA replaced RNA as the unit of genetic information. 
C)  There were no mutations following the evolution of the genetic code. 
D)  The genetic code evolved before the different domains diverged. 
A)  The genetic code evolved three times. 
B)  The genetic code evolved before DNA replaced RNA as the unit of genetic information. 
C)  There were no mutations following the evolution of the genetic code. 
D)  The genetic code evolved before the different domains diverged.

Question 14

The "universal" genetic code is now known to have exceptions. Evidence for this can be found if which of the following is TRUE?

Accepted Answer

A)  if UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only) in a different organism 
B)  if one stop codon, such as UGA, is found to have a different effect on translation than another stop codon, such as UAA 
C)  if prokaryotic organisms are able to translate a eukaryotic mRNA and produce the same polypeptide 
D)  if several codons are found to translate to the same amino acid, such as serine 
E)  if a single mRNA molecule is found to translate to more than one polypeptide when there are two or more AUG sites 
A)  if UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only) in a different organism 
B)  if one stop codon, such as UGA, is found to have a different effect on translation than another stop codon, such as UAA 
C)  if prokaryotic organisms are able to translate a eukaryotic mRNA and produce the same polypeptide 
D)  if several codons are found to translate to the same amino acid, such as serine 
E)  if a single mRNA molecule is found to translate to more than one polypeptide when there are two or more AUG sites

Question 15

The associated figure shows a diagram of blocks of genes on human chromosome 16 and the locations of blocks of similar genes on four chromosomes of the mouse.
The movement of these blocks suggests that ________.

Accepted Answer

A)  during evolutionary time, these sequences have separated and have returned to their original positions 
B)  DNA sequences within these blocks have become increasingly divergent 
C)  sequences represented have duplicated at least three times 
D)  chromosomal translocations have moved blocks of sequences to other chromosomes 
E)  higher mammals have more convergence of gene sequences related in function 
A)  during evolutionary time, these sequences have separated and have returned to their original positions 
B)  DNA sequences within these blocks have become increasingly divergent 
C)  sequences represented have duplicated at least three times 
D)  chromosomal translocations have moved blocks of sequences to other chromosomes 
E)  higher mammals have more convergence of gene sequences related in function

Question 16

Which of the following nucleotide triplets best represents a codon?

Accepted Answer

A)  a triplet separated spatially from other triplets 
B)  a triplet in the middle of a ribosomal RNA molecule 
C)  a triplet at the opposite end of tRNA from the attachment site of the amino acid 
D)  a triplet in the same reading frame as an upstream AUG 
E)  a sequence in tRNA at the 3' end 
A)  a triplet separated spatially from other triplets 
B)  a triplet in the middle of a ribosomal RNA molecule 
C)  a triplet at the opposite end of tRNA from the attachment site of the amino acid 
D)  a triplet in the same reading frame as an upstream AUG 
E)  a sequence in tRNA at the 3' end

Question 17

According to the table and the figure associated with this question, which enzyme is defective in the strain with the arg2 mutation?

Accepted Answer

A)  the enzyme that converts the precursor to ornithine 
B)  the enzyme that converts ornithine to citrulline 
C)  the enzyme that converts citrulline to arginine 
D)  the enzyme that converts the precursor to citrulline 
A)  the enzyme that converts the precursor to ornithine 
B)  the enzyme that converts ornithine to citrulline 
C)  the enzyme that converts citrulline to arginine 
D)  the enzyme that converts the precursor to citrulline

Question 18

Which of the following contradicts the one-gene, one-enzyme hypothesis?

Accepted Answer

A)  A mutation in a single gene can result in a defective protein. 
B)  Alkaptonuria results when individuals lack a single enzyme involved in the catalysis of homogentisic acid. 
C)  Sickle cell anemia results in defective hemoglobin. 
D)  A single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally. 
A)  A mutation in a single gene can result in a defective protein. 
B)  Alkaptonuria results when individuals lack a single enzyme involved in the catalysis of homogentisic acid. 
C)  Sickle cell anemia results in defective hemoglobin. 
D)  A single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally.

Question 19

Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?

Accepted Answer

A)  a base substitution 
B)  a base deletion near the start of a gene 
C)  a base deletion near the end of the coding sequence, but not in the terminator codon 
D)  deletion of three bases near the start of the coding sequence, but not in the initiator codon 
E)  a base insertion near the end of the coding sequence, but not in the terminator codon 
A)  a base substitution 
B)  a base deletion near the start of a gene 
C)  a base deletion near the end of the coding sequence, but not in the terminator codon 
D)  deletion of three bases near the start of the coding sequence, but not in the initiator codon 
E)  a base insertion near the end of the coding sequence, but not in the terminator codon

Question 20

The statement "DNA → RNA → Proteins" ________.

Accepted Answer

A)  is known as the central dogma 
B)  depicts the regulation of gene expression 
C)  is the same in all organisms, as well as viruses and prions 
D)  describes a series of catalytic reactions 
A)  is known as the central dogma 
B)  depicts the regulation of gene expression 
C)  is the same in all organisms, as well as viruses and prions 
D)  describes a series of catalytic reactions

Exam 16: How Genes Work

What does it mean when we say the genetic code is redundant?

Which one of the following is TRUE? A codon ________.

The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?

The following question(s) refer to this table of codons. -What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'

A frameshift mutation could result from ________.

Which of the following DNA mutations is most likely to damage the protein it specifies?

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in ________.

Given the DNA template shown in the associated figure, which of the following bases would you find in a complementary RNA strand and where would they be synthesized?

Beadle and Tatum discovered that metabolic pathways are studied most effectively using which of the following techniques?

A nonsense mutation in a gene ________.

Refer to the metabolic pathway illustrated in the associated figure. If A, B, and C are all required for growth, a strain mutant for the gene encoding enzyme B would be able to grow on medium supplemented with ________.

Which of the following mutations is likely to cause the most dramatic phenotypic change?

All three domains (Bacteria, Archaea, and Eukarya) follow the same genetic code. Therefore, which of the following statements would most likely be correct?

The "universal" genetic code is now known to have exceptions. Evidence for this can be found if which of the following is TRUE?

The associated figure shows a diagram of blocks of genes on human chromosome 16 and the locations of blocks of similar genes on four chromosomes of the mouse. The movement of these blocks suggests that ________.

Which of the following nucleotide triplets best represents a codon?

According to the table and the figure associated with this question, which enzyme is defective in the strain with the arg2 mutation?

Which of the following contradicts the one-gene, one-enzyme hypothesis?

Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?

The statement "DNA → RNA → Proteins" ________.

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Ecosystems and Global Ecology

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes: an Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cellcell Interactions

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Genes, Development, and Evolution

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioral Ecology

Population Ecology

Community Ecology

Biodiversity and Conservation Biology

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