Campbell Biology: Concepts and Connections, 8e (Reece et al.)
Chapter 11 How Genes Are Controlled
11.1 Multiple-Choice Questions
1) The term “gene expression” refers to the
A) fact that each individual of a species has a unique set of genes.
B) fact that individuals of the same species have different phenotypes.
C) process by which genetic information flows from genes to proteins.
D) flow of information from parent to offspring.
2) A gene operon consists of
A) a transcribed gene only.
B) a promoter only.
C) a regulatory gene only.
D) transcribed genes, an operator, and a promoter.
3) In a prokaryote, a group of genes with related functions, along with their associated control
sequences, defines
A) an allele.
B) an operon.
C) a locus.
D) a transposon.
4) The lac operon in Escherichia coli
A) prevents lactose-utilizing enzymes from being expressed when lactose is absent from the
environment.
B) prevents lactose intolerance.
C) prevents lactose-utilizing enzymes from being expressed when lactose is present in the
environment.
D) promotes the expression of lactose-utilizing enzymes when lactose is absent from the
environment.
5) Proteins that bind to DNA and turn on operons by making it easier for RNA polymerase to
bind to a promoter are called
A) regulators.
B) operators.
C) activators.
D) repressors.
6) The lac operon of E. coli is ________ when the repressor is bound to lactose.
A) active
B) inactive
C) cloned
D) unregulated
7) The expression of the tryptophan operon is controlled by
A) a repressor that is active when it is alone.
B) a repressor that is inactive when it binds to lactose.
C) a repressor that is active when it binds to tryptophan.
D) an activator that turns the operon on by binding to DNA.
8) Which of the following is likely to occur in E. coli cells that are grown in skim milk?
A) The lac operon is shut off, and the cells will not produce lactose-utilizing enzymes.
B) The trp repressor is activated, and the cells will produce lactose-utilizing enzymes.
C) The trp operon is turned on, but the bacteria will not produce lactose-utilizing enzymes.
D) The trp operon and the lac operon are both switched off.
9) A single cell, the zygote, can develop into an entirely new organism with many different
specialized cells. Which of the following statements about this process is false?
A) Additional genetic information for the formation of specialized cells is passed on to the
developing embryo via the mother.
B) The descendant cells specialize by a process known as differentiation.
C) The zygote contains all of the genetic information required for the development of many
different cell types.
D) Differentiation of the zygote into a multicellular organism results from selective gene
expression.
10) The basis of cellular differentiation is
A) the operon.
B) selective gene expression.
C) cloning.
D) mutation.
11) The genes for the enzymes of glycolysis
A) are active in all metabolizing cells, but the genes for specialized proteins are expressed only
in particular cell types.
B) are inactive in all metabolizing cells, but the genes for specialized proteins are expressed in
all cell types.
C) and the genes for all specialized proteins are expressed in all metabolizing cells.
D) and the genes for all specialized proteins are expressed in all embryonic cells.
12) Which of the following statements regarding DNA packing is false?
A) A nucleosome consists of DNA wound around a protein core of eight histone molecules.
B) DNA packing tends to promote gene expression.
C) Highly compacted chromatin is generally not expressed at all.
D) Prokaryotes have proteins analogous to histones.
13) The relationship between DNA and chromosomes is most like
A) an egg yolk inside of an egg.
B) a spoon cradling some peas.
C) thread wrapped around a spool.
D) the candy shell surrounding the chocolate in a piece of M&M candy.
14) In female mammals, the inactive X chromosome in each cell
A) can be activated if mutations occur in the active X chromosome.
B) is broken down, and its nucleotides are degraded and reused.
C) is absorbed and used in energy production.
D) becomes a Barr body.
15) The tortoiseshell pattern on a cat
A) usually occurs in males.
B) is the result of a homozygous recessive condition.
C) results from X chromosome inactivation.
D) is a result of alleles on the Y chromosome.
16) Both prokaryotic and eukaryotic cells use ________ to turn certain genes on or off.
A) RNA transcriptase
B) intron segments
C) proteins
D) nucleosome packing
17) Enhancers are
A) adjacent to the gene that they regulate.
B) required to turn on gene expression when transcription factors are in short supply.
C) DNA sequences to which activator proteins bind.
D) required to facilitate the binding of DNA polymerases.
18) There is a mutation in the operator of the trp operon in a cell such that the trp repressor is
unable to bind to the operator. If tryptophan is added to the cell, what will happen?
A) Tryptophan will bind to the repressor, and trp enzymes will be produced.
B) Tryptophan will bind to the repressor, and trp enzymes will not be produced.
C) Tryptophan will not bind to the repressor, and trp enzymes will be produced.
D) Tryptophan will bind to the operator, and trp enzymes will be produced.
19) RNA splicing involves the
A) addition of a nucleotide “cap” to the molecule.
B) addition of a nucleotide “tail” to the molecule.
C) removal of introns from the molecule.
D) removal of exons from the molecule.
20) The coding regions of a gene are called
A) introns.
B) exons.
C) promoters.
D) enhancers.
21) Which of the following permits a single gene to code for more than one polypeptide?
A) retention of different introns in the final version of the different mRNA strands
B) alternative RNA splicing
C) genetic differentiation
D) addition of different types of caps and tails to the final version of the mRNA strands
22) Small pieces of RNA that can regulate translation of mRNA are called
A) microRNA.
B) interfering RNA.
C) transfer RNA.
D) messenger RNA.
23) RNA interference (RNAi) can be used by
A) researchers to induce the production of more mRNA.
B) researchers to artificially turn on gene expression.
C) viruses to stop the production of new proteins.
D) cells to prevent infections from double-stranded RNA viruses.
24) All of the following mechanisms are used to regulate protein production except
A) protein activation.
B) protein breakdown.
C) DNA replication.
D) the breakdown of mRNA.
25) Which of the following mechanisms of controlling gene expression occurs outside of the
nucleus?
A) adding a cap and tail to RNA
B) DNA packing/unpacking
C) RNA splicing
D) translation
26) Which of the following statements about fruit fly development is false?
A) One of the earliest development events is the determination of the head and tail ends of the
egg.
B) The location of the head and tail ends of the egg is primarily determined by the location of
sperm entry during fertilization.
C) Homeotic genes regulate batteries of other genes that direct the anatomical identity of body
parts.
D) Cascades of gene expression routinely direct fruit fly development.
27) A homeotic gene
A) determines which end of the egg will become the head and which end will become the tail.
B) serves as a master control gene that functions during embryonic development by controlling
the developmental fate of groups of cells.
C) represses gene transcription and promotes mRNA translation.
D) is found only in adult somatic cells.
28) Which of the following statements about microarrays is false?
A) Microarrays enable scientists to determine the activity of thousands of genes at once.
B) Microarrays use tiny portions of double-stranded RNA fragments from a large number of
genes.
C) Microarrays are used to determine which genes are active in different tissues or in tissues of
different states of health.
D) Microarrays use fluorescently labeled cDNA molecules to identify particular genes expressed
at a particular time.
29) In multicellular organisms, the coordination of cellular activities relies on
A) cell receptors that detect transcription factors.
B) the availability of certain “key” nutrients as cells divide.
C) operons.
D) cell-to-cell signaling and signal transduction pathways.
30) To initiate a signal transduction pathway, a signal binds to a receptor protein usually located
in the
A) nucleus.
B) plasma membrane.
C) ER.
D) cytoplasm.
31) Transcription factors attach to
A) DNA.
B) signal molecules.
C) plasma membrane receptors.
D) mRNA.
32) A signal outside a cell triggers changes in the transcription and translation inside the cell
through
A) post-translational editing.
B) signal transduction pathways.
C) protein activation.
D) protein breakdown.
33) Yeast are able to communicate with each other
A) by close cell-to-cell contact.
B) through chemical signaling.
C) only if they can touch each other and have merged cell walls.
D) with pseudopodia.
34) Signal transduction pathways
A) are found strictly in multicellular organisms which require cell–to-cell communication.
B) are limited for use in sexual identification.
C) originally evolved in vertebrates.
D) are mechanisms of communication that probably evolved in ancient prokaryotes.
35) In plants, most differentiated cells retain
A) only a tiny fraction of their original set of genes.
B) a complete set of their genes but lose the ability to express most of those genes.
C) a complete set of their genes and retain the ability to express those genes under certain
circumstances.
D) the ability to dedifferentiate but then cannot return to their original differentiated state.
36) Why can some plants be cloned from a single cell?
A) Plant cells do not differentiate even when mature, so any cell can grow into an entire plant.
B) Plant cells can dedifferentiate and give rise to all of the specialized cells required to produce
an entire plant.
C) Plant cells can produce genes to replace those lost during development.
D) Plant cells are capable of self-renewal by utilizing cellular components from adjacent cells.
37) Which of the following processes occurs when a salamander regenerates a lost limb?
A) The homeotic genes of the regenerating limb are expressed.
B) Certain cells in the limb dedifferentiate, divide, and then redifferentiate to form a new limb.
C) A new salamander develops from the lost limb.
D) The homeotic genes of the regenerating cells turn off.
38) The cloning of Dolly the sheep
A) demonstrated that the nuclei from differentiated mammalian cells can retain their full genetic
potential.
B) demonstrated that differentiated cells contain only a fraction of their full genetic potential.
C) demonstrated, for the first time, that eggs are haploid and body cells are diploid.
D) revealed that cloned mammals most resemble the egg donor.
39) The use of cloning to produce special embryonic stem cells is called
A) regenerative cloning.
B) transplantational cloning.
C) reproductive cloning.
D) therapeutic cloning.
40) Which of the following mammals has not yet been cloned and brought through the complete
gestation cycle?
A) cow
B) human
C) pig
D) cat
41) Which of the following possible uses of reproductive cloning is still considered by most to be
an unresolved ethical issue?
A) the production of genetically identical animals for experimentation
B) cloning mammals for the production of potentially valuable drugs
C) the production of organs in cloned pigs for transplant into humans
D) the reproductive cloning of humans
42) Which of the following statements regarding stem cells is false?
A) Embryonic stem cells can give rise to all the different specialized cells in the body.
B) Adult, but not embryonic, stem cells can be grown in laboratory culture.
C) Adult stem cells are present in adult tissues.
D) Adult stem cells are partway along the road to differentiation.
43) Adult stem cells have limited therapeutic potential
A) because they are fully differentiated.
B) because they lack a complete set of genes.
C) due to their excessive numbers in tissues.
D) because their developmental potential is limited to certain tissues.
44) A gene that can cause cancer when present in a single copy in a cell is called a(n)
A) oncogene.
B) enhancer gene.
C) carcinogen.
D) proto-oncogene.
45) Which of the following statements about proto-oncogenes is false?
A) Proto-oncogenes are normal genes with the potential to become oncogenes.
B) Many proto-oncogenes code for growth factors.
C) A mutation must occur in a cell’s DNA for a proto-oncogene to become an oncogene.
D) If a proto-oncogene’s gene product is produced in smaller quantities, a cell may become
cancerous.
46) Which of the following is not a factor that contributes to normal cells becoming cancerous?
A) the conversion of a proto-oncogene to an oncogene
B) damage to a tumor-suppressor gene
C) the production of more effective tumor-suppressor gene products
D) excessive replication of proto-oncogenes
47) Cancer of the colon is caused by
A) a single somatic cell gene mutation.
B) several somatic cell gene mutations.
C) a physical rupture of the colon.
D) a diet high in fiber and low in fat.
48) The development of colon cancer occurs slowly, and colon cancer is more frequently seen in
the elderly than the young. This is most likely because
A) cancer cells don’t have mitochondria, so they grow slowly.
B) usually six or more somatic mutations must occur to give rise to the cancer, which takes time.
C) cancer cells have to wait until new blood vessels grow into the area, which takes much time.
D) most cancer mutations interfere with mitosis, so cell division occurs more slowly.
49) Mutations in the proto-oncogene ras and the tumor suppressor gene p53
A) increase protein synthesis by the cell.
B) can improve the chance of avoiding cancer as one ages.
C) can enhance further mutations, which can develop into cancer.
D) disrupt normal regulation of the cell cycle.
50) Mutations in the p53 gene can lead to cancer by
A) causing the production of excessive amounts of relay proteins.
B) causing the production of a faulty protein that is no longer able to inhibit cell division.
C) promoting the expression of mRNA that can interact with DNA, resulting in new mutations.
D) increasing the production of growth hormones, which trigger faster cell cycles.
51) The carcinogen known to cause the most cases and types of cancer is
A) X-rays.
B) ultraviolet light.
C) alcohol.
D) tobacco.