Campbell Biology; Chapter 11: Worksheet – Flashcards
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The basis of cellular differentiation is A) selective gene expression. B) the operon. C) cloning. D) mutation.
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selective gene expression.
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Adult stem cells have limited therapeutic potential A) because their developmental potential is limited to certain tissues. B) due to their excessive numbers in tissues. C) because they lack a complete set of genes. D) because they are fully differentiated.
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because their developmental potential is limited to certain tissues.
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In plants, most differentiated cells retain A) only a tiny fraction of their original set of genes. B) the ability to dedifferentiate, but then cannot return to their original differentiated state. C) a complete set of their genes, but lose the ability to express most of those genes. D) a complete set of their genes, and retain the ability to express those genes under certain circumstances.
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a complete set of their genes, and retain the ability to express those genes under certain circumstances.
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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.
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plasma membrane.
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Which of the following processes occurs when a salamander regenerates a lost limb? A) The homeotic genes of the regenerating cells turn off. B) A new salamander develops from the lost limb. C) Oncogenes that cause accelerated cell division are turned on. D) Certain cells in the limb dedifferentiate, divide, and then redifferentiate to form a new limb.
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Certain cells in the limb dedifferentiate, divide, and then redifferentiate to form a new limb.
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In multicellular organisms, the coordination of cellular activities relies on A) operons. B) the availability of certain "key" nutrients as cells divide. C) cell receptors that detect transcription factors. D) cell-to-cell signaling and signal transduction pathways.
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cell-to-cell signaling and signal transduction pathways.
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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.
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a repressor that is active when it binds to tryptophan.
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Which of the following statements about proto-oncogenes is false? A) Proto-oncogenes are normal genes with the potential to become oncogenes. B) A mutation in a tumor-suppressor gene can stop cell division immediately. C) A mutation must occur in a cell's DNA for a proto-oncogene to become an oncogene. D) Many proto-oncogenes code for growth factors.
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A mutation in a tumor-suppressor gene can stop cell division immediately.
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In a prokaryote, a group of genes with related functions, along with their associated control sequences, defines A) a locus. B) an operon. C) an allele. D) a transposon.
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an operon.
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The tortoiseshell pattern on a cat A) usually occurs in males. B) results from X chromosome inactivation. C) is the result of a homozygous recessive condition. D) is a result of alleles on the Y chromosome.
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results from X chromosome inactivation.
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The genes for the enzymes of glycolysis A) and the genes for all specialized proteins are expressed in all embryonic cells. B) and the genes for all specialized proteins are expressed in all metabolizing cells. C) are inactive in all metabolizing cells, but the genes for specialized proteins are expressed in all cell types. D) are active in all metabolizing cells, but the genes for specialized proteins are expressed only in particular cell types.
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are active in all metabolizing cells, but the genes for specialized proteins are expressed only in particular cell types.
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Which of the following is not a factor that contributes to normal cells becoming cancerous? A) one or more of the cell's genes being removed by a virus B) damage to a tumor-suppressor gene C) excessive replication of proto-oncogenes D) the conversion of a proto-oncogene to an oncogene
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one or more of the cell's genes being removed by a virus
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A homeotic gene A) determines which end of the egg will become the head and which end will become the tail. B) represses gene transcription and promotes mRNA translation. C) is found only in adult somatic cells. D) serves as a master control gene that functions during embryonic development by controlling the developmental fate of groups of cells.
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serves as a master control gene that functions during embryonic development by controlling the developmental fate of groups of cells.
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Mutations in the p53 gene can lead to cancer by A) increasing the production of growth hormones, which trigger faster cell cycles. B) causing the production of excessive amounts of relay proteins. C) causing the production of a faulty protein that is no longer able to inhibit cell division. D) promoting the expression of mRNA that can interact with DNA, resulting in new mutations.
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causing the production of a faulty protein that is no longer able to inhibit cell division.
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The relationship between DNA and chromosomes is most like A) an egg yolk inside of an egg. B) the candy shell surrounding the chocolate in a piece of M & M candy. C) a spoon cradling some peas. D) thread wrapped around a spool.
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thread wrapped around a spool.
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Enhancers are A) required to turn on gene expression when transcription factors are in short supply. B) required to facilitate the binding of DNA polymerases. C) DNA sequences to which activator proteins bind. D) adjacent to the gene that they regulate.
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DNA sequences to which activator proteins bind.
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Which of the following mechanisms of controlling gene expression occurs outside of the nucleus? A) adding a cap and tail to RNA B) RNA splicing C) translation D) DNA packing/unpacking
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translation
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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 operon is turned on but the bacteria will not produce lactose-utilizing enzymes. C) The trp operon and the lac operon are both switched off. D) The trp repressor is activated and the cells will produce lactose-utilizing enzymes.
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The trp repressor is activated and the cells will produce lactose-utilizing enzymes.
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Transcription factors attach to A) mRNA. B) DNA. C) plasma membrane receptors. D) signal molecules.
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DNA
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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) addition of different types of caps and tails to the final version of the mRNA strands C) genetic differentiation D) alternative RNA splicing
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alternative RNA splicing
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The lac operon in E. coli A) coordinates the production of tryptophan-utilizing enzymes when it is present. B) prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment. C) allows the bacterium to resist antibiotics in the penicillin family. D) regulates the rate of binary fission.
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prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment.
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Silencers A) bind to promoters to promote the start of transcription. B) bind to activators to inhibit the start of transcription. C) bind to enhancers to promote the start of transcription. D) bind to DNA sequences and inhibit the start of transcription.
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bind to DNA sequences and inhibit the start of transcription.
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Which of the following statements regarding stem cells is false? A) Adult stem cells are partway along the road to differentiation. B) Adult stem cells are present in adult tissues. C) Adult, but not embryonic, stem cells can be grown in laboratory culture. D) Embryonic stem cells can give rise to all the different specialized cells in the body.
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Adult, but not embryonic, stem cells can be grown in laboratory culture.
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Small pieces of RNA that can regulate translation of mRNA are called A) minuteRNA. B) monoRNA. C) miniRNA. D) microRNA.
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microRNA.
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Signal transduction pathways A) are mechanisms of communication that probably evolved in ancient prokaryotes. B) are found strictly in multicellular organisms, which require cell-to-cell communication. C) originally evolved in vertebrates. D) are limited for use in sexual identification.
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are mechanisms of communication that probably evolved in ancient prokaryotes.
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Mutations in the proto-oncogene ras and the tumor suppressor gene p53 A) disrupt normal regulation of the cell cycle. B) can enhance further mutations, which can develop into cancer. C) can improve the chance of avoiding cancer as one ages. D) increase protein synthesis by the cell.
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disrupt normal regulation of the cell cycle.
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Proteins that bind to DNA and turn on operons by making it easier for RNA polymerase to bind to a promoter are called A) operators. B) repressors. C) regulators. D) activators.
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activators
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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) The zygote contains all of the genetic information required for the development of many different cell types. B) Differentiation of the zygote into a multicellular organism results from selective gene expression. C) The descendant cells specialize by a process known as differentiation. D) Additional genetic information for the formation of specialized cells is passed on to the developing embryo via the placenta.
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Additional genetic information for the formation of specialized cells is passed on to the developing embryo via the placenta.
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Cancer of the colon is caused by A) the proto-oncogene, lac. B) exposure of colon cells to a mutagen. C) a single gene mutation. D) several somatic cell mutations.
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several somatic cell mutations.
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The use of cloning to produce special embryonic stem cells is called A) therapeutic cloning. B) reproductive cloning. C) regenerative cloning. D) transplantational cloning.
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therapeutic cloning.
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A gene that can cause cancer when present in a single copy in a cell is called a(n) A) enhancer gene. B) oncogene. C) carcinogen. D) proto-oncogene.
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oncogene.
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Which of the following possible uses of reproductive cloning is still considered by most to be an unresolved ethical issue? A) the production of organs in cloned pigs for transplant into humans B) cloning mammals for the production of potentially valuable drugs C) the production of genetically identical animals for experimentation D) the reproductive cloning of humans
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the reproductive cloning of humans
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A gene operon consists of A) a transcribed gene only. B) a regulatory gene only. C) a promoter only. D) transcribed genes, an operator, and a promoter.
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transcribed genes, an operator, and a promoter.
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The coding regions of a gene (the portions that are expressed as polypeptide sequences) are called A) introns. B) exons. C) proto-oncogenes. D) redundant coding sections.
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exons.
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The lac operon of E. coli is ________ when the repressor is bound to lactose. A) unregulated B) cloned C) inactive D) active
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active
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Both prokaryotic and eukaryotic cells use ________ to turn certain genes on or off. A) intron segments B) nucleosome packing C) proteins D) RNA transcriptase
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proteins
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The carcinogen known to cause the most cases and types of cancer is A) tobacco. B) ultraviolet light. C) plutonium. D) alcohol.
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tobacco
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Which of the following statements regarding DNA packing is false? A) Highly compacted chromatin is generally not expressed at all. B) Prokaryotes have proteins analogous to histones. C) DNA packing tends to promote gene expression. D) A nucleosome consists of DNA wound around a protein core of eight histone molecules.
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DNA packing tends to promote gene expression.
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Why can some plants be cloned from a single cell? A) Plant cells can dedifferentiate and give rise to all of the specialized cells required to produce an entire plant. B) Plant cells do not differentiate even when mature, so any cell can grow into an entire plant. C) Plant cells are capable of self-renewal by utilizing cellular components from adjacent cells. D) Plant cells can produce genes to replace those lost during development.
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Plant cells can produce genes to replace those lost during development.
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All of the following mechanisms are used to regulate protein production except A) the breakdown of mRNA. B) protein activation. C) DNA editing. D) protein breakdown.
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DNA editing.
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RNA splicing involves the A) addition of a nucleotide "tail" to the molecule. B) removal of exons from the molecule. C) removal of introns from the molecule. D) addition of a nucleotide "cap" to the molecule.
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removal of introns from the molecule.
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The term "gene expression" refers to the A) fact that each individual of a species has a unique set of genes. B) flow of information from parent to offspring. C) process by which genetic information flows from genes to proteins. D) fact that individuals of the same species have different phenotypes.
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process by which genetic information flows from genes to proteins.
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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 have to wait until new blood vessels grow into the area, which takes much time. B) most cancer mutations interfere with mitosis, so cell division occurs more slowly. C) four or more somatic mutations must occur to give rise to the cancer, which takes time. D) cancer cells don't have mitochondria, so they grow slowly.
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four or more somatic mutations must occur to give rise to the cancer, which takes time.
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miRNA can be used by A) cells to prevent infections from double-stranded RNA viruses. B) viruses to stop the production of new proteins. C) researchers to induce the production of more mRNA. D) researchers to artificially turn on gene expression.
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cells to prevent infections from double-stranded RNA viruses.
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Yeast are able to communicate with each other A) only if they can touch each other and have merged cell walls. B) with pseudopodia. C) through chemical signaling. D) by close cell-to-cell contact.
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through chemical signaling.
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Which of the following statements about fruit fly development is false? A) The location of the head and tail ends of the egg is primarily determined by the location of sperm entry during fertilization. B) Homeotic genes regulate batteries of other genes that direct the anatomical identity of body parts. C) Cascades of gene expression routinely direct fruit fly development. D) One of the earliest development events is the determination of the head and tail ends of the egg.
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The location of the head and tail ends of the egg is primarily determined by the location of sperm entry during fertilization.
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The cloning of Dolly the sheep A) demonstrated that differentiated cells contain only a fraction of their full genetic potential. B) demonstrated, for the first time, that eggs are haploid and body cells are diploid. C) revealed that cloned mammals most resemble the egg donor. D) demonstrated that the nuclei from differentiated mammalian cells can retain their full genetic potential.
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demonstrated that the nuclei from differentiated mammalian cells can retain their full genetic potential.
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A signal outside a cell triggers changes in the transcription and translation inside the cell through A) protein activation. B) signal transduction pathways. C) post-translational editing. D) protein breakdown. 2
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signal transduction pathways.
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Which of the following statements about microarrays is false? A) Microarrays use fluorescently labeled cDNA molecules to identify particular genes expressed at a particular time. B) Microarrays are used to determine which genes are active in different tissues or in tissues of different states of health. C) Microarrays use tiny portions of double-stranded RNA fragments from a large number of genes. D) Microarrays enable scientists to determine the activity of thousands of genes at once.
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Microarrays use tiny portions of double-stranded RNA fragments from a large number of genes.
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In female mammals, the inactive X chromosome in each cell A) is absorbed and used in energy production. B) is broken down, and its nucleotides are degraded and reused. C) can be activated if mutations occur in the active X chromosome. D) becomes a Barr body.
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becomes a Barr body.
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Which of the following mammals has not yet been cloned and brought through the complete gestation cycle? A) pig B) human C) cow D) cat
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human
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Which of the following statements regarding cancer risk factors is false? A) Mutagens are usually not carcinogens. B) Factors that alter DNA and make cells cancerous are called carcinogens. C) Eating 20-30 grams of plant fiber daily and reducing the intake of animal fat can reduce your risk of developing colon cancer. D) X-rays and ultraviolet radiation are two of the most potent carcinogens.
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Mutagens are usually not carcinogens.
