Question 1

How might a single base substitution in the sequence of a gene affect the amino acid sequence of a protein encoded by the gene, and why?

Accepted Answer

A)  The amino acid sequence would be substantially altered, because the reading frame would change with a single base substitution. 
B)  It is not possible for a single base substitution to affect protein structure, because each codon is three bases long. 
C)  Only a single amino acid could change, because the reading frame is unaffected. 
D)  All amino acids following the substitution would be affected, because the reading frame would be shifted. 
A)  The amino acid sequence would be substantially altered, because the reading frame would change with a single base substitution. 
B)  It is not possible for a single base substitution to affect protein structure, because each codon is three bases long. 
C)  Only a single amino acid could change, because the reading frame is unaffected. 
D)  All amino acids following the substitution would be affected, because the reading frame would be shifted.

Question 2

Once researchers identified DNA as the unit of inheritance, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. What is the mechanism of information transfer?

Accepted Answer

A)  Lipids are soluble in the nuclear membrane and serve to transfer information from the DNA to the cytoplasm, where protein synthesis takes place. 
B)  Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place. 
C)  Proteins transfer information from the nucleus to the ribosome, where protein synthesis takes place. 
D)  DNA from a single gene is replicated and transferred to the cytoplasm, where it serves as a template for protein synthesis. 
A)  Lipids are soluble in the nuclear membrane and serve to transfer information from the DNA to the cytoplasm, where protein synthesis takes place. 
B)  Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place. 
C)  Proteins transfer information from the nucleus to the ribosome, where protein synthesis takes place. 
D)  DNA from a single gene is replicated and transferred to the cytoplasm, where it serves as a template for protein synthesis.

Question 3

What is a codon?

Accepted Answer

A)  the amino acetyl tRNA synthase that ensures that the correct amino acid is added to the right tRNA 
B)  the complementarity of DNA and RNA 
C)  the three- base sequence of mRNA that specifies the addition of a specific amino acid 
D)  the base sequence of the tRNA that brings the correct amino acid to the ribosome where protein synthesis will take place 
A)  the amino acetyl tRNA synthase that ensures that the correct amino acid is added to the right tRNA 
B)  the complementarity of DNA and RNA 
C)  the three- base sequence of mRNA that specifies the addition of a specific amino acid 
D)  the base sequence of the tRNA that brings the correct amino acid to the ribosome where protein synthesis will take place

Question 4

Figure 16.3
Above is a metabolic pathway for the synthesis of an amino acid E), without which an organism could not live. Enzymes are represented by numbers, and substrates by letters. Use this figure for the next  questions.
-According to the figure above, if enzyme 3 was nonfunctional in an organism, which of the following outcomes would you predict?

Accepted Answer

A)  The cell would die because of a lack of the essential amino acid. 
B)  Substrate C would accumulate, and there would be no substrate D formed. 
C)  Lack of enzyme 3 would result in a cessation halt) of the entire metabolic pathway. 
D)  Another enzyme would be able to catalyze the reaction and the pathway would proceed. 
A)  The cell would die because of a lack of the essential amino acid. 
B)  Substrate C would accumulate, and there would be no substrate D formed. 
C)  Lack of enzyme 3 would result in a cessation halt) of the entire metabolic pathway. 
D)  Another enzyme would be able to catalyze the reaction and the pathway would proceed.

Question 5

All three domains Bacteria, Archaea, and Eukarya) follow the same genetic code. Which of the following statements would most likely be accurate given that information?

Accepted Answer

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

Question 6

The proteome is all the proteins produced by an organism. The genome is the totality of all genes of an organism. If the proteome is much larger than the genome, which of the following statements would be accurate?

Accepted Answer

A)  The number of monomeric subunits found in proteins is fewer than the number of monomeric subunits found in genes. 
B)  Noncoding DNA is important in determining the proteome. 
C)  This finding lends support to the one gene-one enzyme hypothesis. 
D)  At least in some cases, a single gene must code for more than one protein. 
A)  The number of monomeric subunits found in proteins is fewer than the number of monomeric subunits found in genes. 
B)  Noncoding DNA is important in determining the proteome. 
C)  This finding lends support to the one gene-one enzyme hypothesis. 
D)  At least in some cases, a single gene must code for more than one protein.

Question 7

According to the central dogma, what molecule should go in the blank? DNA - _ - Proteins

Accepted Answer

A)  chaperone molecules 
B)  complementary DNA 
C)  transport molecules 
D)  mRNA 
A)  chaperone molecules 
B)  complementary DNA 
C)  transport molecules 
D)  mRNA

Question 8

Use the figure to answer the following questions).
   Figure 16.5
-Refer to Figure 16.5. A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence Phe- Leu- Ile- Val would be

Accepted Answer

A)  3' AAA- GAA- TAA- CAA 5'. 
B)  5' TTG- CTA- CAG- TAG 3'. 
C)  3' AAC- GAC- GUC- AUA 5'. 
D)  3' AAA- AAT- ATA- ACA 5'. 
E)  5' AUG- CTG- CAG- TAT 3'. 
A)  3' AAA- GAA- TAA- CAA 5'. 
B)  5' TTG- CTA- CAG- TAG 3'. 
C)  3' AAC- GAC- GUC- AUA 5'. 
D)  3' AAA- AAT- ATA- ACA 5'. 
E)  5' AUG- CTG- CAG- TAT 3'.

Question 9

The term "point" in point mutation is in reference to which of the following?

Accepted Answer

A)  If affects only one nucleotide. 
B)  It affects only one type of chromosome 
C)  It affects an organism once during its lifespan. 
D)  It affects only one protein in the body. 
A)  If affects only one nucleotide. 
B)  It affects only one type of chromosome 
C)  It affects an organism once during its lifespan. 
D)  It affects only one protein in the body.

Question 10

Which of the following observations may have resulted in the hypothesis that a codon is made up of three bases?

Accepted Answer

A)  A codon of 2 bases in length, from 4 different bases, would code for a maximum of 16 different amino acids; therefore, 2 are too few. 
B)  A codon of 3 bases in length, from 4 different bases, would code for a maximum of 12 different amino acids; therefore 3 are too few. 
C)  A codon of 4 bases in length, from 4 different bases, could code for a maximum of 24 different amino acids; therefore, 4 is likely. 
D)  A codon of 3 bases in length, from 4 different bases, would code for a maximum of 64 different amino acids; therefore, 3 is possible. 
A)  A codon of 2 bases in length, from 4 different bases, would code for a maximum of 16 different amino acids; therefore, 2 are too few. 
B)  A codon of 3 bases in length, from 4 different bases, would code for a maximum of 12 different amino acids; therefore 3 are too few. 
C)  A codon of 4 bases in length, from 4 different bases, could code for a maximum of 24 different amino acids; therefore, 4 is likely. 
D)  A codon of 3 bases in length, from 4 different bases, would code for a maximum of 64 different amino acids; therefore, 3 is possible.

Question 11

The synthesis of RNA through complementary base pairing is known as

Accepted Answer

A)  transcription. 
B)  translation. 
C)  semiconservative replication. 
D)  dispersive polymerization. 
A)  transcription. 
B)  translation. 
C)  semiconservative replication. 
D)  dispersive polymerization.

Question 12

Figure 16.1
 $\begin{array}{|l|l|l|l|l|}
\hline \text { Mutant Strain } & \text { Medium with: } & \text { Medium with: } & \text { Medium with: } & \text { Medium with: } \
& \text { No ornithine } & \text { Ornithine } & \text { No ornithine } & \text { No ornithine } \
& \text { No citrulline } & \text { No citrulline } & \text { Citrulline } & \text { No citrulline } \
& \text { No arginine } & \text { No arginine } & \text { No Arginine } & \text { Arginine } \
\hline \text { argl } & \text { no growth } & \text { GROWTH } & \text { GROWTH } & \text { GROWTH } \
\hline \text { arg2 } & \text { no growth } & \text { no growth } & \text { GROWTH } & \text { GROWTH } \
\hline \text { arg3 } & \text { no growth } & \text { no growth } & \text { no growth } & \text { GROWTH } \
\hline
\end{array}$   
-According to the table and Figure 16.1, which enzyme is defective in the strain with the arg2 mutation?

Accepted Answer

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

Question 13

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

Accepted Answer

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

Question 14

The original DNA has the base sequence AGCGTTACCGT; a mutation in the DNA strand results in the base sequence AGGCGTTACCGT. What does this tell you about the mutation?

Accepted Answer

A)  It was caused by radiation poisoning. 
B)  It may result in a single amino acid change in the protein being coded for by this base sequence. 
C)  It is a frameshift mutation. 
D)  There is no mutation. 
A)  It was caused by radiation poisoning. 
B)  It may result in a single amino acid change in the protein being coded for by this base sequence. 
C)  It is a frameshift mutation. 
D)  There is no mutation.

Question 15

Use the figure to answer the following questions).
   Figure 16.5
-Refer to Figure 16.5. If the codon CAC was present in the ribosome A site, which amino acid would be added?

Accepted Answer

A)  methionine 
B)  histidine 
C)  phenylalanine 
D)  aspartic acid 
A)  methionine 
B)  histidine 
C)  phenylalanine 
D)  aspartic acid

Question 16

Figure 16.4
-A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is

Accepted Answer

A)  3' UCA 5'. 
B)  3' UGS 5'. 
C)  3' ACU 5'. 
D)  5' TCA 3'. 
E)  either UCA or TCA, depending on wobble in the first base. 
A)  3' UCA 5'. 
B)  3' UGS 5'. 
C)  3' ACU 5'. 
D)  5' TCA 3'. 
E)  either UCA or TCA, depending on wobble in the first base.

Question 17

What feature makes organisms less vulnerable to small mutations in DNA replication that are not corrected?

Accepted Answer

A)  redundancy in the genetic code 
B)  pleiotropy 
C)  differential gene expression 
D)  alternative splicing 
A)  redundancy in the genetic code 
B)  pleiotropy 
C)  differential gene expression 
D)  alternative splicing

Question 18

The statement, DNA -RNA -Proteins,

Accepted Answer

A)  describes a series of catalytic reactions. 
B)  is reversible in most living organisms. 
C)  has become known as the central dogma. 
D)  depicts the regulation of gene expression. 
A)  describes a series of catalytic reactions. 
B)  is reversible in most living organisms. 
C)  has become known as the central dogma. 
D)  depicts the regulation of gene expression.

Question 19

There are three stop codons nonsense codons); all remaining codons specify addition of an amino acid sense codons). How many sense codons are there?

Accepted Answer

A)  20 
B)  45 
C)  61 
D)  72 
A)  20 
B)  45 
C)  61 
D)  72

Exam 16: How Genes Work

How might a single base substitution in the sequence of a gene affect the amino acid sequence of a protein encoded by the gene, and why?

Once researchers identified DNA as the unit of inheritance, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. What is the mechanism of information transfer?

What is a codon?

All three domains Bacteria, Archaea, and Eukarya) follow the same genetic code. Which of the following statements would most likely be accurate given that information?

The proteome is all the proteins produced by an organism. The genome is the totality of all genes of an organism. If the proteome is much larger than the genome, which of the following statements would be accurate?

According to the central dogma, what molecule should go in the blank? DNA - _ - Proteins

Use the figure to answer the following questions). Figure 16.5 -Refer to Figure 16.5. A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence Phe- Leu- Ile- Val would be

The term "point" in point mutation is in reference to which of the following?

Which of the following observations may have resulted in the hypothesis that a codon is made up of three bases?

The synthesis of RNA through complementary base pairing is known as

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

The original DNA has the base sequence AGCGTTACCGT; a mutation in the DNA strand results in the base sequence AGGCGTTACCGT. What does this tell you about the mutation?

Use the figure to answer the following questions). Figure 16.5 -Refer to Figure 16.5. If the codon CAC was present in the ribosome A site, which amino acid would be added?

Figure 16.4 -A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is

What feature makes organisms less vulnerable to small mutations in DNA replication that are not corrected?

The statement, DNA -RNA -Proteins,

There are three stop codons nonsense codons); all remaining codons specify addition of an amino acid sense codons). How many sense codons are there?

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

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes

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

Gene Structure and Development

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

Behavioural Ecology

Population Ecology

Community Ecology

Ecosystems and Global Ecology

Biodiversity and Conservation Biology

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