MOLECULAR BIOLOGY OF THE CELL, SIXTH EDITION f f f f f f
CHAPTER 1: CELLS AND GENOMES f f f f f
© Garland Science 2015
f f f
1 Scientists discover more than ten thousand new species of living organisms every year.
f f f f f f f f f f f f
fWhat is shared between all of these organisms?
f f f f f f f
A. They are made of cells, whose nuclei enclose their DNA.
f f f f f f f f f
B. They obtain their energy from sunlight.
f f f f f
C. They produce and use adenosine triphosphate (ATP).
f f f f f f
D. Their genome contains at least 1000 genes.
f f f f f f
E. All of the above.
f f f
2 All cells … f f
A. have membrane transport proteins.f f f
B. synthesize proteins on the ribosome. f f f f
C. replicate their genome by DNA polymerization. f f f f f
D. transcribe their genetic information by RNA polymerization. f f f f f f
E. All of the above. f f f
3 Imagine a segment of DNA (within a gene) encoding a certain amount of information in its
f f f f f f f f f f f f f f f
nucleotide sequence. When this segment is fully transcribed into mRNA and then translated into
f f f f f f f f f f f f f f
protein, in general, …
f f f f
A. the protein sequence would carry more information compared to the DNA and mRNA
f f f f f f f f f f f f
sequences, because its alphabet has 20 letters.
f f f f f f f
f B. the protein sequence would carry less information compared to the DNA and mRNA
f f f f f f f f f f f f f
sequences, because several codons can correspond to one amino acid.
f f f f f f f f f f
C. the amount of information in the mRNA sequence is lower, because the mRNA has
f f f f f f f f f f f f f
been transcribed using only one of the DNA strands as the template.
f f f f f f f f f f f f
D. the amount of information in the mRNA sequence is higher, because several mRNA
f f f f f f f f f f f f
molecules can be transcribed from one DNA molecule.
f f f f f f f f
4 Which of the following processes that happens inside a cell DOES NOT normally require
f f f f f f f f f f f f f
consumption of free energy by the cell?
f f f f f f f
, A. Replication of the genetic material f f f f
B. Import of nutrients from the environment f f f f f
C. Diffusion of small molecules within the cell f f f f f f
D. Regulation of gene expression f f f
E. Synthesis of enzymes that catalyze cellular reactions f f f f f f
5 Which of the following would you N OT expect to find in a bacterial cell?
f f f f f f f f f f f f f f
A. Swimming using flagella f f
B. Having a cell wall around the plasma membrane f f f f f f f
f C. ATP production in mitochondria
f f f f
D. Protein production on the ribosome f f f f
E. Sexual exchange of DNA with other bacteria f f f f f f
6 To trace family relationships between distantly related organisms such as humans, algae,
f f f f f f f f f f f
bacteria, and archaea, one should compare their genomes in regions …
f f f f f f f f f f f
A. that evolve rapidly. f f
B. that have a higher mutation rate.
f f f f f
C. that code for proteins. f f f
D. where mutations are hardly tolerated. f f f f
E. where most mutations are selectively neutral. f f f f f
7 Laboratory strains of the model organism Escherichia coli that are resistant to antibiotics f f f f f f f f f f f f
are very often used in research laboratories as well as in the biotechnology industry. If cultures of
f f f f f f f f f f f f f f f f f
such bacteria were allowed to contaminate the environment uncontrollably, it is possible that at
f f f f f f f f f f f f f f
some point, pathogenic bacteria such as Neisseria meningitidis (which causes meningitis and can
f f f f f f f f f f f f f
cause death, especially in children) could acquire the same antibiotic-resistance gene, causing a
f f f f f f f f f f f f f
meningitis outbreak that is difficult to treat. In this scenario, which of the following mechanisms is
f f f f f f f f f f f f f f f f
a more likely source of the antibiotic-resistance gene in N. meningitidis?
f f f f f f f f f f f
A. Random new gene generation f f f
B. Intragenic mutation f
C. Gene duplication f
D. DNA segment shuffling f f
E. Horizontal gene transfer f f
8 A virus …f f
A. is a type of cell. f f f f
, B. has genetic material made of proteins.
f f f f f
C. can only infect a single host species.
f f f f f f
D. can act as a vector for gene transfer.
f f f f f f f
E. cannot persist in its host for more than one cell generation.
f f f f f f f f f f
9 Which of the following does NOT typically involve horizontal gene transfer?
f f f f f f f f f f
A. Sexual reproduction in humans f f f
B. Bacteriophage infection of bacteria f f f
C. The evolutionary history of the eukaryotic cell
f f f f f f
D. The accidental duplication of a small region of a bacterial chromosome followed by
f f f f f f f f f f f f
cell division f f
E. Introduction of plasmids into bacteria in a laboratory f f f f f f f
10 Gene duplication can give rise to homologous genes that are part of gene families. For
f f f f f f f f f f f f f f
example, there are six actin genes in the genome of most mammalian species. In humans, the ACTB
f f f f f f f f f f f f f f f f f
gene, which encodes a cytoskeletal actin, is expressed ubiquitously, while ACTC1 is expressed
f f f f f f f f f f f f f
mainly in cardiac cells. Although bacteria lack the eukaryotic cytoskeletal organization, the
f f f f f f f f f f f f
bacterial MreB gene bears recognizable sequence similarity to mammalian actin genes and codes
f f f f f f f f f f f f f
for a protein that is similar to actin in structure and function. Which of the following statements is
f f f f f f f f f f f f f f f f f f
true about these genes?
f f f f
A. ACTB is homologous to ACTC1 but not to MreB. f f f f f f f f
B. ACTB is orthologous to ACTC1 but not to MreB. f f f f f f f f
C. ACTB is paralogous to ACTC1 but not to MreB. f f f f f f f f
D. MreB is orthologous to ACTB but not to ACTC1. f f f f f f f f
E. ACTB is paralogous to both ACTC1 and MreB. f f f f f f f
11 Out of nearly 5000 protein-coding gene families, there is a set of nearly 300 conserved gene
f f f f f f f f f f f f f f f
families that are found in species from all domains of life. When one looks at the general functions
f f f f f f f f f f f f f f f f f f
f assigned to these gene families, it is found that …
f f f f f f f f f
A. the majority of them function in cell-to-cell signaling.
f f f f f f f
B. the majority of them are poorly characterized. f f f f f f
C. more than one-third of them are involved in translation or amino acid transport
f f f f f f f f f f f f
and m etabolism. f f f
D. more than one-half of the shared families are involved in DNA replication
f f f f f f f f f f f
and transcription.
f f
E. Nearly all of them are involved in energy production and carbohydrate metabolism.
f f f f f f f f f f f
, 12 Which of the following is true regarding Escherichia coli?
f f f f f f f f
A. Most of our understanding about mitosis comes from studies on this model organism.
f f f f f f f f f f f f
B. It is a rod-shaped bacterium that can only grow in the gut of humans and
f f f f f f f f f f f f f f
other vertebrates.
f f
C. Two strains of E. coli can differ by up to 0.1% in their genomes. D
f f f f f f f f f f f f f f
. E. coli strain K-12 encodes about 4300 proteins.
f f f f f f f f f
E. The E. coli (strain K-12) genome is about 430 million nucleotide pairs long.
f f f f f f f f f f f f f
13 Which of the following is NOT true regarding the tree of life?
f f f f f f f f f f f
A. Most bacteria and archaea have 1000 to 6000 genes in their genomes.
f f f f f f f f f f f
B. Eukaryotes are more similar to archaea than to bacteria with respect to the f f f f f f f f f f f f
proteins that act on their DNA.
f f f f f f
C. Most bacteria and archaea have genome sizes between one and ten million nucleotide
f f f f f f f f f f f f
pairs, whereas eukaryotic genomes can be millions of times larger.
f f f f f f f f f f
D. Archaeal species were thought to belong to the eukaryotic world before f f f f f f f f f f
sequence analysis placed them in a separate domain of life.
f f f f f f f f f f
E. Photosynthetic bacteria are thought to be the ancestors of the eukaryotic chloroplasts. f f f f f f f f f f f
14 A mutation in the cdc28 gene in the budding yeast Saccharomyces cerevisiae causes cell-
f f f f f f f f f f f f f
cycle arrest, giving rise to unbudded cells that look like “dumbbells.” Treatment of wild-type cells
f f f f f f f f f f f f f f f
with nocodazole, a drug that destabilizes some cytoskeletal polymers, leads to a similar phenotype.
f f f f f f f f f f f f f f
Based only on these observations, which statement is true regarding cdc28?
f f f f f f f f f f f
A. cdc28 codes for a master regulatory kinase that phosphorylates other proteins.
f f f f f f f f f f
B. Nocodazole binds to the protein coded by the cdc28 gene. f f f f f f f f f
C. The product of the cdc28 gene is responsible for resistance to nocodazole.
f f f f f f f f f f f
D. The product of the cdc28 gene is involved in cell cycle regulation.
f f f f f f f f f f f
E. The product of cdc28 destabilizes the same cytoskeletal polymers that
f f f f f f f f f
nocodazole also destabilizes.
f f f
15 Which of the following structures is exclusively found in eukaryotic cells?
f f f f f f f f f f
A. Plasma membrane f
B. Cell wall f
C. Chromosome
D. Ribosome
E. Lysosome
CHAPTER 1: CELLS AND GENOMES f f f f f
© Garland Science 2015
f f f
1 Scientists discover more than ten thousand new species of living organisms every year.
f f f f f f f f f f f f
fWhat is shared between all of these organisms?
f f f f f f f
A. They are made of cells, whose nuclei enclose their DNA.
f f f f f f f f f
B. They obtain their energy from sunlight.
f f f f f
C. They produce and use adenosine triphosphate (ATP).
f f f f f f
D. Their genome contains at least 1000 genes.
f f f f f f
E. All of the above.
f f f
2 All cells … f f
A. have membrane transport proteins.f f f
B. synthesize proteins on the ribosome. f f f f
C. replicate their genome by DNA polymerization. f f f f f
D. transcribe their genetic information by RNA polymerization. f f f f f f
E. All of the above. f f f
3 Imagine a segment of DNA (within a gene) encoding a certain amount of information in its
f f f f f f f f f f f f f f f
nucleotide sequence. When this segment is fully transcribed into mRNA and then translated into
f f f f f f f f f f f f f f
protein, in general, …
f f f f
A. the protein sequence would carry more information compared to the DNA and mRNA
f f f f f f f f f f f f
sequences, because its alphabet has 20 letters.
f f f f f f f
f B. the protein sequence would carry less information compared to the DNA and mRNA
f f f f f f f f f f f f f
sequences, because several codons can correspond to one amino acid.
f f f f f f f f f f
C. the amount of information in the mRNA sequence is lower, because the mRNA has
f f f f f f f f f f f f f
been transcribed using only one of the DNA strands as the template.
f f f f f f f f f f f f
D. the amount of information in the mRNA sequence is higher, because several mRNA
f f f f f f f f f f f f
molecules can be transcribed from one DNA molecule.
f f f f f f f f
4 Which of the following processes that happens inside a cell DOES NOT normally require
f f f f f f f f f f f f f
consumption of free energy by the cell?
f f f f f f f
, A. Replication of the genetic material f f f f
B. Import of nutrients from the environment f f f f f
C. Diffusion of small molecules within the cell f f f f f f
D. Regulation of gene expression f f f
E. Synthesis of enzymes that catalyze cellular reactions f f f f f f
5 Which of the following would you N OT expect to find in a bacterial cell?
f f f f f f f f f f f f f f
A. Swimming using flagella f f
B. Having a cell wall around the plasma membrane f f f f f f f
f C. ATP production in mitochondria
f f f f
D. Protein production on the ribosome f f f f
E. Sexual exchange of DNA with other bacteria f f f f f f
6 To trace family relationships between distantly related organisms such as humans, algae,
f f f f f f f f f f f
bacteria, and archaea, one should compare their genomes in regions …
f f f f f f f f f f f
A. that evolve rapidly. f f
B. that have a higher mutation rate.
f f f f f
C. that code for proteins. f f f
D. where mutations are hardly tolerated. f f f f
E. where most mutations are selectively neutral. f f f f f
7 Laboratory strains of the model organism Escherichia coli that are resistant to antibiotics f f f f f f f f f f f f
are very often used in research laboratories as well as in the biotechnology industry. If cultures of
f f f f f f f f f f f f f f f f f
such bacteria were allowed to contaminate the environment uncontrollably, it is possible that at
f f f f f f f f f f f f f f
some point, pathogenic bacteria such as Neisseria meningitidis (which causes meningitis and can
f f f f f f f f f f f f f
cause death, especially in children) could acquire the same antibiotic-resistance gene, causing a
f f f f f f f f f f f f f
meningitis outbreak that is difficult to treat. In this scenario, which of the following mechanisms is
f f f f f f f f f f f f f f f f
a more likely source of the antibiotic-resistance gene in N. meningitidis?
f f f f f f f f f f f
A. Random new gene generation f f f
B. Intragenic mutation f
C. Gene duplication f
D. DNA segment shuffling f f
E. Horizontal gene transfer f f
8 A virus …f f
A. is a type of cell. f f f f
, B. has genetic material made of proteins.
f f f f f
C. can only infect a single host species.
f f f f f f
D. can act as a vector for gene transfer.
f f f f f f f
E. cannot persist in its host for more than one cell generation.
f f f f f f f f f f
9 Which of the following does NOT typically involve horizontal gene transfer?
f f f f f f f f f f
A. Sexual reproduction in humans f f f
B. Bacteriophage infection of bacteria f f f
C. The evolutionary history of the eukaryotic cell
f f f f f f
D. The accidental duplication of a small region of a bacterial chromosome followed by
f f f f f f f f f f f f
cell division f f
E. Introduction of plasmids into bacteria in a laboratory f f f f f f f
10 Gene duplication can give rise to homologous genes that are part of gene families. For
f f f f f f f f f f f f f f
example, there are six actin genes in the genome of most mammalian species. In humans, the ACTB
f f f f f f f f f f f f f f f f f
gene, which encodes a cytoskeletal actin, is expressed ubiquitously, while ACTC1 is expressed
f f f f f f f f f f f f f
mainly in cardiac cells. Although bacteria lack the eukaryotic cytoskeletal organization, the
f f f f f f f f f f f f
bacterial MreB gene bears recognizable sequence similarity to mammalian actin genes and codes
f f f f f f f f f f f f f
for a protein that is similar to actin in structure and function. Which of the following statements is
f f f f f f f f f f f f f f f f f f
true about these genes?
f f f f
A. ACTB is homologous to ACTC1 but not to MreB. f f f f f f f f
B. ACTB is orthologous to ACTC1 but not to MreB. f f f f f f f f
C. ACTB is paralogous to ACTC1 but not to MreB. f f f f f f f f
D. MreB is orthologous to ACTB but not to ACTC1. f f f f f f f f
E. ACTB is paralogous to both ACTC1 and MreB. f f f f f f f
11 Out of nearly 5000 protein-coding gene families, there is a set of nearly 300 conserved gene
f f f f f f f f f f f f f f f
families that are found in species from all domains of life. When one looks at the general functions
f f f f f f f f f f f f f f f f f f
f assigned to these gene families, it is found that …
f f f f f f f f f
A. the majority of them function in cell-to-cell signaling.
f f f f f f f
B. the majority of them are poorly characterized. f f f f f f
C. more than one-third of them are involved in translation or amino acid transport
f f f f f f f f f f f f
and m etabolism. f f f
D. more than one-half of the shared families are involved in DNA replication
f f f f f f f f f f f
and transcription.
f f
E. Nearly all of them are involved in energy production and carbohydrate metabolism.
f f f f f f f f f f f
, 12 Which of the following is true regarding Escherichia coli?
f f f f f f f f
A. Most of our understanding about mitosis comes from studies on this model organism.
f f f f f f f f f f f f
B. It is a rod-shaped bacterium that can only grow in the gut of humans and
f f f f f f f f f f f f f f
other vertebrates.
f f
C. Two strains of E. coli can differ by up to 0.1% in their genomes. D
f f f f f f f f f f f f f f
. E. coli strain K-12 encodes about 4300 proteins.
f f f f f f f f f
E. The E. coli (strain K-12) genome is about 430 million nucleotide pairs long.
f f f f f f f f f f f f f
13 Which of the following is NOT true regarding the tree of life?
f f f f f f f f f f f
A. Most bacteria and archaea have 1000 to 6000 genes in their genomes.
f f f f f f f f f f f
B. Eukaryotes are more similar to archaea than to bacteria with respect to the f f f f f f f f f f f f
proteins that act on their DNA.
f f f f f f
C. Most bacteria and archaea have genome sizes between one and ten million nucleotide
f f f f f f f f f f f f
pairs, whereas eukaryotic genomes can be millions of times larger.
f f f f f f f f f f
D. Archaeal species were thought to belong to the eukaryotic world before f f f f f f f f f f
sequence analysis placed them in a separate domain of life.
f f f f f f f f f f
E. Photosynthetic bacteria are thought to be the ancestors of the eukaryotic chloroplasts. f f f f f f f f f f f
14 A mutation in the cdc28 gene in the budding yeast Saccharomyces cerevisiae causes cell-
f f f f f f f f f f f f f
cycle arrest, giving rise to unbudded cells that look like “dumbbells.” Treatment of wild-type cells
f f f f f f f f f f f f f f f
with nocodazole, a drug that destabilizes some cytoskeletal polymers, leads to a similar phenotype.
f f f f f f f f f f f f f f
Based only on these observations, which statement is true regarding cdc28?
f f f f f f f f f f f
A. cdc28 codes for a master regulatory kinase that phosphorylates other proteins.
f f f f f f f f f f
B. Nocodazole binds to the protein coded by the cdc28 gene. f f f f f f f f f
C. The product of the cdc28 gene is responsible for resistance to nocodazole.
f f f f f f f f f f f
D. The product of the cdc28 gene is involved in cell cycle regulation.
f f f f f f f f f f f
E. The product of cdc28 destabilizes the same cytoskeletal polymers that
f f f f f f f f f
nocodazole also destabilizes.
f f f
15 Which of the following structures is exclusively found in eukaryotic cells?
f f f f f f f f f f
A. Plasma membrane f
B. Cell wall f
C. Chromosome
D. Ribosome
E. Lysosome
