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Chapter 19: Eukaryotic Genomes: Organization, Regulation, and Evolution
 
Chapter Quiz
 

Chapter Quiz


1 .       There are thought to be about _____ genes in a human cell. (Overview E-Book) [Hint]

 30
 300
 3,000
 30,000
 300,000
2 .       The chromatin of a eukaryotic nucleus consists mainly of _____. (Concept 19.1E-Book) [Hint]

 pigments that function in aerobic respiration
 masses of ribosomal RNA that are condensing into ribosomes
 linear strands of DNA complexed with large amounts of protein
 amphipathic proteins with toxic hydrophobic regions
 none of the above
3 .       In eukaryotes, the structures consisting of associations of histones and DNA are called _____. (Concept 19.1E-Book) [Hint]

 histosomes
 nucleosomes
 ribosomes
 genetosomes
 dinasomes
4 .       Nucleosomes are structures in the nucleus that are used to _____. (Concept 19.1E-Book) [Hint]

 bind to and help process mRNA after it has been synthesized
 plug the nuclear pores except when specifically recognized molecules pass through
 wrap the DNA to organize it and make it more compact
 synthesize ribosomes
 do all of these
5 .       Nucleosomes include all of the following histone proteins except _____. (Concept 19.1E-Book) [Hint]

 H1
 H2A
 H2B
 H3
 H4
6 .       During interphase, chromatin can exist in the form of _____. (Concept 19.1E-Book) [Hint]

 10-nm fiber only
 30-nm fiber only
 looped domains only
 10-nm fiber or 30-nm fiber
 10-nm fiber, 30-nm fiber, or looped domains
7 .       During interphase, _____ can be seen with a light microscope. (Concept 19.1E-Book) [Hint]

 nucleosomes
 introns
 heterochromatin
 transposons
 euchromatin
8 .       Active genes are associated with the loosely packed chromatin called _____. (Concept 19.1E-Book) [Hint]

 euchromatin
 heterochromatin
 leucine zippers
 zinc fingers
 heterodimers
9 .       Gene expression in animals is regulated primarily by _____. (Concept 19.2E-Book) [Hint]

 controlling gene packing and unpacking
 controlling the transcription of genes into mRNA
 controlling the translation of mRNA into protein
 transcription factors encoded for by mitochondrial DNA
 selectively breaking down the proteins encoded by the genes
10 .       The control of gene expression is more complex in multicellular eukaryotes than in prokaryotes because _____. (Concept 19.2E-Book) [Hint]

 eukaryotic cells are much smaller
 in a multicellular eukaryote, different cells are specialized for different functions
 prokaryotes are restricted to stable environments
 eukaryotic chromosomes have fewer nucleotides; therefore, each nucleotide sequence must do several jobs
 the genes of eukaryotes provide information for making proteins
11 .       Which of the following is true of gene regulation in both eukaryotes and prokaryotes? (Concept 19.2E-Book) [Hint]

 Packing of DNA in chromosomes is elaborate.
 Transcription is the usual point at which gene expression is regulated.
 A cap and a tail are added to mRNA.
 Genes are organized into operons.
 Noncoding portions of RNA are removed in the making of mRNA.
12 .       In eukaryotes, DNA packing seems to affect gene expression primarily by _____. (Concept 19.2E-Book) [Hint]

 controlling access to DNA
 positioning related genes near each other
 protecting DNA from mutations
 enhancing the recombination of genes
 allowing unpacked genes to be eliminated from the genome
13 .       A scientist clones a regulatory gene that is involved in controlling the expression of other genes, and discovers that the regulatory gene encodes a histone deacetylase enzyme. It is likely that this enzyme regulates gene expression by _____. (Concept 19.2E-Book) [Hint]

 causing tighter packing of the chromatin at the target gene, thereby inhibiting transcription
 causing looser packing of the chromatin at the target gene, thereby inhibiting transcription
 causing tighter packing of the chromatin at the target gene, thereby enhancing transcription
 causing looser packing of the chromatin at the target gene, thereby enhancing transcription
 causing tighter packing of the chromatin at the target gene, thereby inhibiting translation
14 .       In a eukaryote, activating transcription factors may stimulate gene expression by binding to a DNA site called a(n) _____. (Concept 19.2E-Book) [Hint]

 operon
 histone
 enhancer
 promoter
 silencer
15 .       Enhancers _____. (Concept 19.2E-Book) [Hint]

 increase the rate of transcription
 are found in eukaryotic genomes
 may be located upstream or downstream from the genes they regulate
 may be located thousands of base pairs away from the promoter
 all of the above
16 .       Dioxin, produced as a by-product of various industrial chemical processes, is suspected of causing cancer and birth defects in animals and humans. It apparently acts by entering cells and binding to specific proteins, which then enter the nucleus and alter the pattern of gene expression. Therefore, dioxin acts by mimicking the action of _____. (Concept 19.2E-Book) [Hint]

 proteins of the mitochondria
 DNA polymerase
 steroid hormones
 enhancers
 histones
17 .       Post-transcriptional controls _____. (Concept 19.2E-Book) [Hint]

 can include translational controls
 can affect mRNA stability
 may regulate the rate at which a molecule is translated
 can regulate mRNA splicing
 all of the above
18 .       Which one of the following is not a means of controlling eukaryotic gene expression? (Concept 19.2E-Book) [Hint]

 DNA packing
 transcriptional regulation
 mRNA processing
 methylation of DNA
 All of the above play a role in the regulation of gene expression.
19 .       RNA interference (RNAi) refers to the _____. (Concept 19.2E-Book) [Hint]

 destruction of RNA molecules having a sequence complementary to an introduced double-stranded RNA
 ability of mRNA to hybridize to the DNA template and inhibit DNA replication
 inhibition of the activity of certain enzymes by RNA molecules mimicking their normal substrates
 tendency of mRNA to get stuck in the nuclear pores, blocking all movement of molecules into and out of the nucleus
 hijacking of most cellular functions by retroviruses upon infection
20 .       What is the role of proteasons? (Concept 19.2E-Book) [Hint]

 They are giant protein complexes that recognize ubiquitin and degrade the tagged proteins.
 They inject double-stranded RNA into a cell, turning off a gene with the same sequence.
 They encode for products that help prevent uncontrolled cell growth.
 They are segments of noncoding DNA that help regulate transcription by binding certain proteins.
 None of the above.


21 .       A cancer cell _____. (Concept 19.3E-Book) [Hint]

 is typically more than 10 times larger than a normal cell
 usually does not contain a nucleus
 does not respond to the chemical signals that control cell division
 requires less nutrients than a normal cell
 is correctly described by all of the above
22 .       In the human genome, oncogenes _____. (Concept 19.3E-Book) [Hint]

 stimulate cell division
 slow cell division
 suppress tumors
 promote cell adhesion
 enhance DNA repair
23 .       DNA damage acts as an intracellular signal passed via protein kinases that leads to inactivation of the _____, which through various mechanisms prevents a cell from passing on mutations due to DNA damage. (Concept 19.3E-Book) [Hint]

 ras gene
 p53 gene
 p21 gene
 the Ras protein
 a proto-oncogene
24 .       Most human cancers are _____. (Concept 19.3E-Book) [Hint]

 caused by the accumulation of somatic mutations
 caused by viruses
 inherited from one parent, like an autosomal dominant allele
 inherited from both parents, like an autosomal recessive allele
 caused by radiation
25 .       There is about 1,000 times as much DNA in a human cell as in an E. coli cell, but only about 10 times as many genes. What accounts for this discrepancy? (Concept 19.4E-Book) [Hint]

 A human cell has much more noncoding DNA.
 The DNA packing is much more complex in a prokaryotic cell.
 Most of the genes in a human cell are turned off.
 E. coli bacteria are less able to respond to their environment than humans.
 Human cells are much larger than E. coli cells.
26 .       The eukaryotic genome is much less tidy and compact than the genomes of prokaryotes. Eukaryotes, but not prokaryotes, have _____. (Concept 19.4E-Book) [Hint]

 a large proportion of their DNA that is never expressed
 introns, some of which are bigger than the genes they interrupt
 short sequences of nucleotides that may be repeated thousands of times
 all of the above
 none of the above
27 .       Who discovered "jumping genes" (transposons)? (Concept 19.4E-Book) [Hint]

 Chase
 Tatum
 McClintock
 Crick
 Pauling
28 .       Segments of eukaryotic DNA that can move from one site to another in the genome by means of an RNA intermediate are called _____. (Concept 19.4E-Book) [Hint]

 alleles
 plasmids
 transposons
 introns
 retrotransposons
29 .       Multigene families arise as a result of _____. (Concept 19.4E-Book) [Hint]

 transformation
 errors during DNA replication and recombination
 RNA splicing
 protein degradation
 the action of restriction enzymes
30 .       Genomic sequences that resemble functional genes, but which are nonfunctional because of numerous mutations in their promoters or coding regions, are called _____. (Concept 19.4E-Book) [Hint]

 pseudogenes
 false genes
 genetic remnants
 quasigenes
 garbage genes
31 .       Gene duplication can ultimately give rise to all of the following except _____. (Concept 19.5E-Book) [Hint]

 pseudogenes
 structurally related genes with entirely different functions
 two closely related versions of a gene that are expressed in different tissues, or at different times during development
 groups of genes with identical functions, but entirely unrelated sequences
 groups of identical genes that are expressed together
32 .       Alu elements can contribute to genomic evolution by _____. (Concept 19.5E-Book) [Hint]

 introducing new splice sites into introns, leading to the production of novel proteins
 integrating into promoters, leading to increased transcription rates
 hybridizing to mRNAs and targeting them for degradation
 promoting pairing between telomeres, dramatically increasing the efficiency of the telomerase enzyme
 stimulating oncogene expression





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