Chapter 21 Flashcards
(38 cards)
For mapping studies of genomes, most of which were far along before 2000, the three-stage method was often used. Which of the following is the usual order in which the stages were performed, assuming some overlap of the three?
A) genetic map, sequencing of fragments, physical map
B) linkage map, physical map, sequencing of fragments
C) sequencing of entire genome, physical map, genetic map
D) cytogenetic linkage, sequencing, physical map
E) physical map, linkage map, sequencing
B) linkage map, physical map, sequencing of fragments
What is the difference between a linkage map and a physical map?
A) For a linkage map, markers are spaced by recombination frequency, whereas for a physical map they are spaced by numbers of base pairs (bp).
B) For a physical map, the ATCG order and sequence must be achieved; however, it does not for the linkage map.
C) For a linkage map, it is shown how each gene is linked to every other gene.
D) For a physical map, the distances must be calculable in units such as nanometers.
E) There is no difference between the two except in the type of pictorial representation.
A) For a linkage map, markers are spaced by recombination frequency, whereas for a physical map they are spaced by numbers of base pairs (bp).
How is a physical map of the genome of an organism achieved?
A) using recombination frequency
B) using very high-powered microscopy
C) using restriction enzyme cutting sites
D) using sequencing of nucleotides
E) using DNA fingerprinting via electrophoresis
C) using restriction enzyme cutting sites
Which of the following most correctly describes a shotgun technique for sequencing a genome?
A) genetic mapping followed immediately by sequencing
B) physical mapping followed immediately by sequencing
C) cloning large genome fragments into very large vectors such as YACs, followed by sequencing
D) cloning several sizes of fragments into various size vectors, ordering the clones, and then sequencing them
E) cloning the whole genome directly, from one end to the other
D) cloning several sizes of fragments into various size vectors, ordering the clones, and then sequencing them
The biggest problem with the shotgun technique is its tendency to underestimate the size of the genome. Which of the following might best account for this?
A) skipping some of the clones to be sequenced
B) missing some of the overlapping regions of the clones
C) counting some of the overlapping regions of the clones twice
D) having some of the clones die during the experiment and therefore not be represented
E) missing some duplicated sequences
E) missing some duplicated sequences
What is metagenomics?
A) genomics as applied to a species that most typifies the average phenotype of its genus
B) the sequence of one or two representative genes from several species
C) the sequencing of only the most highly conserved genes in a lineage
D) sequencing DNA from a group of species from the same ecosystem
E) genomics as applied to an entire phylum
D) sequencing DNA from a group of species from the same ecosystem
Which procedure is not required when the shotgun approach to sequencing is modified as sequencing by synthesis, in which many small fragments are sequenced simultaneously? A) use of restriction enzymes B) sequencing each fragment C) cloning each fragment into a plasmid D) ordering the sequences E) PCR amplification
C) cloning each fragment into a plasmid
What is bioinformatics?
A) a technique using 3-D images of genes in order to predict how and when they will be expressed
B) a method that uses very large national and international databases to access and work with sequence information
C) a software program available from NIH to design genes
D) a series of search programs that allow a student to identify who in the world is trying to sequence a given species
E) a procedure that uses software to order DNA sequences in a variety of comparable ways
B) a method that uses very large national and international databases to access and work with sequence information
What is proteomics?
A) the linkage of each gene to a particular protein
B) the study of the full protein set encoded by a genome
C) the totality of the functional possibilities of a single protein
D) the study of how amino acids are ordered in a protein
E) the study of how a single gene activates many proteins
B) the study of the full protein set encoded by a genome
Bioinformatics can be used to scan sequences for probable genes looking for start and stop sites for transcription and for translation, for probable splice sites, and for sequences known to be found in other known genes. Such sequences containing these elements are called A) expressed sequence tags. B) cDNA. C) multigene families. D) proteomes. E) short tandem repeats.
A) expressed sequence tags.
A microarray known as a GeneChip, with most now-known human protein coding sequences, has been developed to aid in the study of human cancer by first comparing two to three subsets of cancer subtypes. What kind of information might be gleaned from this GeneChip to aid in cancer prevention?
A) information about whether or not a patient has this type of cancer prior to treatment
B) evidence that might suggest how best to treat a person’s cancer with chemotherapy
C) data that could alert patients to what kind of cancer they were likely to acquire
D) information about which parent might have provided a patient with cancer-causing genes
E) information on cancer epidemiology in the United States or elsewhere
C) data that could alert patients to what kind of cancer they were likely to acquire
What is gene annotation in bioinformatics?
A) finding transcriptional start and stop sites, RNA splice sites, and ESTs
B) describing the functions of protein-coding genes
C) describing the functions of noncoding regions of the genome
D) matching the corresponding phenotypes of different species
E) comparing the protein sequences within a single phylum
A) finding transcriptional start and stop sites, RNA splice sites, and ESTs
Why is it unwise to try to relate an organism’s complexity with its size or number of cells?
A) A very large organism may be composed of very few cells or very few cell types.
B) A single-celled organism, such as a bacterium or a protist, still has to conduct all the complex life functions of a large multicellular organism.
C) A single-celled organism that is also eukaryotic, such as a yeast, still reproduces mitotically.
D) A simple organism can have a much larger genome.
E) A complex organism can have a very small and simple genome.
B) A single-celled organism, such as a bacterium or a protist, still has to conduct all the complex life functions of a large multicellular organism.
Fragments of DNA have been extracted from the remnants of extinct woolly mammoths, amplified, and sequenced. These can now be used to
A) introduce into relatives, such as elephants, certain mammoth traits.
B) clone live woolly mammoths.
C) study the relationships among woolly mammoths and other wool-producers.
D) understand the evolutionary relationships among members of related taxa.
E) appreciate the reasons why mammoths went extinct.
D) understand the evolutionary relationships among members of related taxa.
If humans have 2,900 Mb, a specific member of the lily family has 120,000 Mb, and a yeast has ~13 Mb, why can’t this data allow us to order their evolutionary significance?
A) Size matters less than gene density.
B) Size does not compare to gene density.
C) Size does not vary with gene complexity.
D) Size is mostly due to “junk” DNA.
E) Size is comparable only within phyla.
C) Size does not vary with gene complexity.
Which of the following is a representation of gene density?
A) Humans have 2,900 Mb per genome.
B) C. elegans has ~20,000 genes.
C) Humans have ~20,000 genes in 2,900 Mb.
D) Humans have 27,000 bp in introns.
E) Fritillaria has a genome 40 times the size of a human.
C) Humans have ~20,000 genes in 2,900 Mb.
Why might the cricket genome have 11 times as many base pairs as that of Drosophila melanogaster?
A) The two insect species evolved at very different geologic eras.
B) Crickets have higher gene density.
C) Drosophila are more complex organisms.
D) Crickets must have more noncoding DNA.
E) Crickets must make many more proteins.
D) Crickets must have more noncoding DNA.
The comparison between the number of human genes and those of other animal species has led to many conclusions, including
A) the density of the human genome is far higher than in most other animals.
B) the number of proteins expressed by the human genome is far more than the number of its genes.
C) most human DNA consists of genes for protein, tRNA, rRNA, and miRNA.
D) the genomes of other organisms are most significantly smaller than the human genome.
B) the number of proteins expressed by the human genome is far more than the number of its genes.
Barbara McClintock, who achieved fame for discovering that genes could move within genomes, had her meticulous work ignored for nearly four decades, but eventually won the Nobel Prize. Why was her work so distrusted?
A) The work of women scientists was still not allowed to be published.
B) Geneticists did not want to lose their cherished notions of DNA stability.
C) There were too many alternative explanations for transposition.
D) She allowed no one else to duplicate her work.
E) She worked only with maize, which was considered “merely” a plant.
B) Geneticists did not want to lose their cherished notions of DNA stability.
What is the most probable explanation for the continued presence of pseudogenes in a genome such as our own?
A) They are genes that had a function at one time, but that have lost their function because they have been translocated to a new location.
B) They are genes that have accumulated mutations to such a degree that they would code for different functional products if activated.
C) They are duplicates or near duplicates of functional genes but cannot function because they would provide inappropriate dosage of protein products.
D) They are genes with significant inverted sequences.
E) They are genes that are not expressed, even though they have nearly identical sequences to expressed genes.
E) They are genes that are not expressed, even though they have nearly identical sequences to expressed genes.
What characteristic of short tandem repeat DNA makes it useful for DNA fingerprinting?
A) The number of repeats varies widely from person to person or animal to animal.
B) The sequence of DNA that is repeated varies significantly from individual to individual.
C) The sequence variation is acted upon differently by natural selection in different environments.
D) Every racial and ethnic group has inherited different short tandem repeats.
A) The number of repeats varies widely from person to person or animal to animal.
Alu elements account for about 10% of the human genome. What does this mean?
A) Alu elements cannot be transcribed into RNA.
B) Alu elements evolved in very ancient times, before mammalian radiation.
C) Alu elements represent the result of transposition.
D) No Alu elements are found within individual genes.
E) Alu elements are cDNA and therefore related to retrotransposons.
C) Alu elements represent the result of transposition.
A multigene family is composed of
A) multiple genes whose products must be coordinately expressed.
B) genes whose sequences are very similar and that probably arose by duplication.
C) the many tandem repeats such as those found in centromeres and telomeres.
D) a gene whose exons can be spliced in a number of different ways.
E) a highly conserved gene found in a number of different species.
B) genes whose sequences are very similar and that probably arose by duplication.
Which of the following can be duplicated in a genome?
A) DNA sequences above a minimum size only
B) DNA sequences below a minimum size only
C) entire chromosomes only
D) entire sets of chromosomes only
E) sequences, chromosomes, or sets of chromosomes
E) sequences, chromosomes, or sets of chromosomes
