Biology chapter 24 - multiple choice
E
Comparisons of human and mouse genomes reveals (1 point) a. they have widely different numbers of genes, and share only a few more genes than humans and pufferfish. b. the differences between humans and mice are mainly the introns. c. they have very little in common. d. the genomes are very similar, with most of the genes unique to mice linked to size and shape. e. the genomes are very similar, with most of the genes unique to mice linked to smell and reproduction.
A
Gene inactivation is likely to produce (1 point) a. pseudogenes. b. orthologs. c. paralogs. d. homologs. e. horizontal gene transfer (HGT).
C
Genome sequencing of the parasitic protist Plasmodium falciparum has been completed. One of the results is (1 point) a. we now know how amazingly similar it is genetically to its host, Anopheles. b. we now know how amazingly similar it is genetically to its host, Drosophila. c. we now have a possible way to attack Plasmodium, through its chloroplast-like apicoplast. d. we no longer have to be concerned with any diseases it might carry.
C
Genome studies show us that many genes and gene families are highly (1 point) a. active. b. variable. c. conserved. d. associational. e. endogenous.
C
Genomes evolve at different rates because (1 point) a. the mutation rate differs in different species. b. exposure to radiation and mutagens differs in different species. c. the generation time differs in different species. d. selection pressures vary in different species. e. gene flow differs in different species.
D
Looking at the differences in protein-encoding gene sequences between humans and chimpanzees (1 point) a. there are vast differences. b. they are about 50% alike. c. they are about 80% alike. d. there is less than 1% difference. e. they are identical, the differences are in the RNA sequences.
B
One of the reasons that pufferfish are a good species to compare to humans is because (1 point) a. it is so easy to hybridize the two and investigate the consequences. b. they are so distantly related that it's easy to distinguish mutually conserved sequences. c. the introns are often identical. d. of the rapid response time in pufferfish to artificial selection. e. they have been separated for so many millions of years and yet the gene sequence is almost identical.
C
One of the ways that two species can be compared, and information about the genetic basis of human diseases extracted, is by using their sequenced genomes and (1 point) a. looking at the allelic differences. b. investigating the introns. c. looking at the conserved sequences. d. exchanging genomic information between them.
E
One possible explanation for why humans are humans and chimps are chimps despite the great similarities in their gene-coding sequences is (1 point) a. allelic control of development. b. the vast differences in exons. c. the vast differences in the introns. d. the "junk" DNA contains important sequences. e. differences in gene expression.
D
Over long sequences within a chromosome (1 point) a. human and mouse DNA is dramatically different in base pair arrangement. b. the linear order of genes is amazingly different, they have transposed. c. the linear order of genes is amazingly different, they have reversed. d. the linear order of genes is the same, indicating conservation of synteny. e. the linear order of genes is the same, indicating conservation of neoteny.
A
Pseudogenes are (1 point) a. DNA sequences similar to functional genes, but do not produce functionalproducts as far as we can tell. b. DNA sequences produced in the laboratory and artificially inserted into a genome to investigate their function. c. duplicate genes that are on the wrong chromosome but still produce the same gene product as the original gene. d. genes that have been inserted from a different species, such as by a retrovirus, and may or may not produce a functional product in the new species. e. mutated genes that produce two or more functional products.
E
Regarding the differences between the human genome and the tiger pufferfish genome (1 point) a. little can be said since pufferfish are not vertebrates—they are too different to compare. b. essentially all the human genes have nearly identical counterparts in pufferfish. c. the order of genes along the chromosomes in both species is essentially identical. d. both species have about the same amount of introns and "nonsense" sequences of DNA. e. about 25% of the human genes are unique when compared to the tiger pufferfish.
B
Some of the olfactory receptor (OR) genes in humans (1 point) a. have mutated dramatically away from the same genes in other primates. b. have been inactivated, reducing our olfactory capabilities compared to other primates. c. have been activated, enhancing our olfactory sense compared to other primates. d. have duplicated more frequently, resulting in increased paralogs compared to other primates. e. have been conserved more rigidly, resulting in increased orthologs compared to other primates.
C
The best explanation for why a mouse develops into a mouse and not a human is(1 point) a.most of the coding genes are different. b. most of the non-coding genes are different. c. gene expression differs. d. the genes are mostly the same but have been rearranged. e. synteny has not been conserved.
B
The genomes of Arabidopsis thaliana, a small member of the mustard family of plants, and rice, Oryza sativa, have been sequenced. The findings include (1 point) a. the genome for each is almost identical, indicating that they diverged in the fairly recent past. b. they each have very high copy numbers (slightly divergent copies of a gene), probably indicating episodes of polyploidy and/or segmental duplication. c. repetitive DNA, including retrotransposons, was a very small proportion of both genomes. d. more than 90% of the genes in each were particular to plants and not found in animal or fungal genomes.
D
The human genome (1 point) a. has no foreign DNA, it is excised by DNAases when it occurs. b. has a very small amount of foreign DNA, mostly in the end caps (telomeres) of chromosomes. c. has a lot of foreign DNA, mostly in the end caps (telomeres) of chromosomes. d. has a lot of foreign DNA scattered throughout the genome, including transposons.
D
The types of human genes least likely to be duplicated, resulting in multiple copies, are (1 point) a. growth and development genes. b. immune system genes. c. genes for cell surface receptors. d. genes controlling basic metabolism.
E
There are at least 6 ways that genomes undergo change. They include all of the following except (1 point) a. mutation of a single gene. b. regions of DNA duplicate. c. large chunks of chromosomes are rearranged within the chromosome (translocation, inversion). d. an entire chromosome is duplicated (trisomy). e. regions of DNA from 3 or more chromosomes form a new chromosome (multisomy).
C
Today, gene swapping between two species is (1 point) a. illegal and irresponsible. b. impossible, but it happened frequently in the distant past. c. infrequent but possible; it happened more often in the distant past. d. much more frequent than in the distant past. e. only possible if they are in the same family of organisms, such as lions and tigers.
A
Using the newly sequenced genomes from each of the kingdoms, it is possible (1 point) a. to explore genetic differences between species very directly, examining DNA changes. b. to build, from scratch, complex organisms with trans-kingdom genomes. c. to sequence and build, from scratch, simple organisms with trans-kingdom genomes. d. to design humans with a variety of inter-kingdomic abilities built into their DNA.
B
When a segment of DNA duplicates, causing 2 or more copies of a gene to be present in the chromosome, the most likely fate of the duplicate(s) would not be (1 point) a. to lose function in subsequent mutation. b. to improve function in subsequent mutation. c. to gain a new function in subsequent mutation. d. to become a pseudogene. e. to become part of a gene family.
A
When an entire genome duplicates so that 3 or more complete copies of the genome exist in each cell (1 point) a. that is the major cause of polyploidy. b. that is a primary cause of some types of birth defects. c. that is a major cause of divergence and speciation. d. that is a primary cause of some types of cancer in somatic cells.
A
Which one of the following statements about the role of genome analysis in crop improvement is false? (1 point) a. Conservation of synteny will hinder our ability to find agriculturally important genes in plants. b. Arabidopsis has no commercial significance except as a model organism. c. Sequencing of the rice genome was important because it is related to many other cereal crop plants. d. Sequencing the genomes of beneficial microbes has already begun. e. Insertion of genes from beneficial microbes into plant genomes can be used to improve crop yields.
B
Which one of the following statements comparing the human and chimpanzee genomes is false? (1 point) a. A comparison of genomes confirms that humans and chimpanzees are sibling species. b. Very few mutations seen in the two genomes occur in coding DNA. c. Some insertion-deletions (indels) lead to loss of function changes in the two genomes. d. More similarity exists between the genomes of human and chimpanzee than between human and mouse. e. The estimated genome sizes and number of genes is very similar in humans and chimpanzees.
E
Which one of the following statements comparing the human and mouse genomes is false? (1 point) a. Human and mouse have about the same number of genes. b. The human genome shares 99% of its genes with the mouse. c. A comparison of genomes confirms that mouse and humans shared a common ancestor more recently than humans and pufferfish. d. Conservation of genes has been great in the two genomes. e. Little rearrangement of genes has occurred in the two genomes.
C
Which one of the following statements comparing the human and tiger pufferfish genomes is false? (1 point) a. Genes regulating the basic cellular metabolism are conserved in both human and pufferfish. b. About 25% of human genes have no counterpart in the pufferfish genome. c. Being ancestral to humans, the pufferfish genome has more repetitive DNA than the human genome. d. Overall, the pufferfish genome has less DNA than the human genome. e. Gene rearranging has been extensive in the genomes of the two vertebrates.
D
Which one of the following statements describing what we know about Plasmodium falciparum, the parasitic protist that causes malaria, is false? (1 point) a. P. falciparum has many genes with similar function clustered together on its chromosomes. b. P. falciparum is difficult for the immune system to target because it "cloaks" itself inside of red blood cells. c. P. falciparum has inherited a unique subcellular organelle called an apicoplast from the chloroplast of an alga. d. Although the P. falciparum apicoplast has no known function, targeting the apicoplast with chloroplast-specific herbicides might kill the parasite.
A
One of the unexpected findings to occur in comparing mouse and human genomes is (1 point) a. that "junk" DNA may be more functional than we assumed. b. how incredibly different they are. c. that there is far more "junk" DNA than we ever thought. d. how similar some gene families are to their original transposons. e. that there is far less "junk" DNA than we ever thought.
B
Which of the following statements about orthologs and paralogs is false? (1 point) a. Orthologs are likely to have the same function. b. Both orthologs and paralogs result from gene duplication. c. The sequence of an ortholog is more likely to be conserved. d. Paralogs are more likely to be pseudogenes than orthologs. e. Paralogs often evolve new functions.
B
Which of the following statements about the role of polyploidization in the evolution of plant genomes is false? (1 point) a. Jumping of transposons is most common in the first few generations following a polyploidization event. b. Genome size in plants is largely determined by polyploidization events. c. Genome downsizing following allopolyploidy usually affects the participating hybrids unequally. d. Genome downsizing following allopolyploidy results mainly from duplicate gene loss. e. The genomes of some current crop plants show evidence of multiple polyploidization events.
A
Which one of the following factors was probably most involved with the reduced sense of smell in humans compared with the other great apes? (1 point) a. pseudogenes b. conservation of synteny c. aneuploidy d. humans have one more chromosome than the other great apes e. number of olfactory receptor (OR) genes present in the genome
A
Which one of the following shows the correct sequence of events involving allopolyploidy that gave rise to modern tobacco? (1 point) a. hybridization, chromosome doubling, duplicate gene loss b. hybridization, duplicate gene loss, chromosome doubling c. chromosome doubling, hybridization duplicate gene loss d. duplicate gene loss, hybridization, chromosome doubling
E
Which one of the following statements about duplicate genes is false? (1 point) a. Duplicate genes can lose their ancestral function through subsequent mutation. b. Duplicate genes can gain a derived function through subsequent mutation. c. Duplicate genes can share the ancestral function of the original gene. d. Gene duplication is most likely to occur in growth and development genes, immune system genes, and cell-surface receptor genes. e. Duplicate genes usually share the same pattern of gene expression.
C
Which one of the following statements about foreign DNA in the human genome is false? (1 point) a. Most of the foreign DNA in the human genome is ancient. b. Most of the foreign DNA in the human genome exists as transposons. c. Like the Drosophila genome, the human genome is constantly eliminating its foreign DNA. d. Little new foreign DNA is entering the human genome.
C
Which one of the following statements about gene function and expression in chimps and humans is false? (1 point) a. Little genetic divergence has occurred since chimps and humans shared a common ancestor. b. Except for about 1% of their genomes, chimp and human genes are identical. c. Using microarrays to detect mRNA transcribed from known human genes, it was possible to show that almost identical transcription patterns existed in the brains of both chimp and human. d. The extra chromosome found in the other great apes contains few novel genes not present in the human genome.
A
Which one of the following statements about genome analysis and human disease detection and treatment is false? (1 point) a. Conserved sequences important to the genetic basis of a human disease are most easily detected by comparison to closely related genomes. b. The genomes of the mammalian relatives of humans are the best targets for discovering new treatments for human diseases. c. Comparing the genomes of parasite and host is likely to reveal good drug targets to eliminate the parasite without harming the host. d. A comparison of mouse and human genomes would help reveal functions for previously unidentified human genes. e. A comparison of human and pufferfish genomes would help observed DNA sequences that were preserved over long periods of time.
A
Which one of the following statements about genome size and gene number in animals is false? (1 point) a. There is a strong correlation between the number of genes and genome size. b. As the human genome was sequenced, the estimated number of genes continued to decrease. c. Much of the extra DNA in humans is in the form of introns. d. The pufferfish as about the same of genes as humans but many fewer introns in its coding DNA. e. Genome size differences depend to a large extent on the amount of retrotransposon DNA present.
C
Which one of the following statements about genome size and gene number in plants is false? (1 point) a. Plants have an even greater genome size range than animals. b. Most plants have about 30,000 to 40,000 genes. c. The difference between genome sizes in wheat and rice can be explained by the fact that wheat is hexaploid (6n) while rice is diploid (2n). d. In plants, gene families have relatively high copy numbers. e. Forces that increase genome size include polyploidy, proliferation of transposable elements, and gene duplication.
C
Which one of the following statements about horizontal gene transfer is false? (1 point) a. Horizontal gene transfer is also called lateral gene transfer. b. Horizontal gene transfer involves hitchhiking genes from other species. c. Horizontal gene transfer was common early in life, but is absent today. d. Gene swapping is evident in the human genome. e. The products of horizontal gene transfer often exist as transposons.
E
Which one of the following statements about pseudogenes is false? (1 point) a. Premature stop codons can produce pseudogenes. b. Missense mutations can produce pseudogenes. c. Pseudogenes cause gene inactivation. d. Pseudogenes have DNA sequences very similar to a functional gene. e. Pseudogenes result from horizontal gene transfer.
A
Which one of the following statements about synteny is true? (1 point) a. Synteny refers to the conservation of gene order along chromosomes. b. Synteny refers to the constancy of chromosome numbers in related clades. c. Synteny results from polyploidization events. d. Synteny refers to the rearrangement of gene order due to inversions. e. Synteny is only observed in closely related clades.
E
Which one of the following statements about the evolution of speech is false? (1 point) a. In humans a single point mutation in the FOXP2 gene impairs speech and grammar. b. FOXP2 may be involved in songbird singing and mouse vocalization. c. The protein coded by the FOXP2 gene differs by only two amino acids in humans and chimps. d. The FOXP2 gene is involved in the control of the neuromuscular pathway leading to complex sound formation. e. FOXP2 codes for a hormone that directly targets the muscles of the larynx and mouth.
D
Which one of the following statements about the genomes of plants (especially Arabidopsis and rice), animals, and fungi is false? (1 point) a. Plants, animals, and fungi share most of the same genes for intermediary metabolism, genome replication, and protein synthesis. b. "Plant" genes include those coding for photosynthetic pathways and morphology. c. Plants generally have larger genomes than animals and fungi. d. Rice has fewer genes than humans. e. About 80% of the genomes of Arabidopsis and rice are the same.
B
Which one of the following statements about the possible regulatory functions of non-protein-coding DNA is false? (1 point) a. A significant amount of the non-protein-coding DNA consists of retrotransposon DNA. b. Non-protein-coding DNA may code for RNAs that are translated into transcription factors. c. A study of mouse RNA transcripts showed that many did not code for any known mouse protein. d. A large part of the non-protein-coding DNA may be rich in regulatory RNA sequences. e. Non-protein-coding DNA in mouse and human is located in comparable regions of their genomes.
