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BS161 Biology Final Exam With Answers (194 Solved Questions)

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    BS 161 FINAL EXAM WITH COMPLETE SOLUTIONS ( 3 VERSIONS) VERSION 1 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)She worked only with maize, which was considered "merely" a plant. B)Geneticists did not want to lose their cherished notions of DNA stability. C)She allowed no one else to duplicate her work. D)The work of women scientists was still not allowed to be published. E)There were too many alternative explanations for transposition. - B Which of the following is a representation of gene density? A)Humans have ~20,000 genes in 2,900 Mb. B)C. elegans has ~20,000 genes. C)Fritillaria has a genome 40 times the size of a human. D)Humans have 27,000 bp in introns. E)Humans have 2,900 Mb per genome. - A 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 is mostly due to "junk" DNA. B)Size does not vary with gene complexity. C)Size does not compare to gene density. D)Size is comparable only within phyla. E)Size matters less than gene density. - B Fragments of DNA have been extracted from the remnants of extinct woolly mammoths, amplified, and sequenced. These can now be used to A)appreciate the reasons why mammoths went extinct. B)introduce into relatives, such as elephants, certain mammoth traits.

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    C)clone live woolly mammoths. D)study the relationships among woolly mammoths and other wool-producers. E)understand the evolutionary relationships among members of related taxa - E 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 simple organism can have a much larger genome. C)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. D)A complex organism can have a very small and simple genome. E)A single-celled organism that is also eukaryotic, such as a yeast, still reproduces mitotically. - C What is metagenomics? A)genomics as applied to an entire phylum B)genomics as applied to a species that most typifies the average phenotype of its genus 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)the sequence of one or two representative genes from several species - D Which of the following most correctly describes a shotgun technique for sequencing a genome? A)physical mapping followed immediately by sequencing B)cloning large genome fragments into very large vectors such as YACs, followed by sequencing C)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 E)genetic mapping followed immediately by sequencing - D What is the difference between a linkage map and a physical map? A)For a physical map, the ATCG order and sequence must be achieved; however, it does not for the linkage map. B)For a linkage map, it is shown how each gene is linked to every other gene.

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    C)For a physical map, the distances must be calculable in units such as nanometers. D)For a linkage map, markers are spaced by recombination frequency, whereas for a physical map they are spaced by numbers of base pairs (bp). E)There is no difference between the two except in the type of pictorial representation. - D In large scale, genome-wide association studies in humans, correlation is sought between A)single nucleotide polymorphisms found in families with a particular introns sequence. B)lengthy sequences that might be shared by most members of a population. C)large inversions that displace the centromere. D)single nucleotide polymorphisms found only in persons with a particular disorder. E)single nucleotide polymorphisms in two or more adjacent genes. - D Which of the following modifications is least likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis? A)methylating the cytosine bases within the DNA fragment B)altering the nucleotide sequence of the DNA fragment C)increasing the length of the DNA fragment D)neutralizing the negative charges within the DNA fragment E)decreasing the length of the DNA fragment - B In yeast signal transduction, the yeast cells A)secrete molecules that result in response by other yeast cells. B)must physically and directly interact. C)produce signal molecules that change themselves so they can interact with one another. D)produce response molecules that diffuse to other yeast cells. E)mate, after which the new cells secrete hybrid signals. - A Which of the following is true for the signaling system in an animal cell that lacks the ability to produce GTP? A)It would employ a transduction pathway directly from an external messenger. B)It could activate only the epinephrine system. C)It would not be able to activate and inactivate the G protein on the cytoplasmic side of the

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    plasma membrane. D)It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. E)It would be able to carry out reception and transduction but would not be able to respond to a signal. - C Because most receptors are membrane proteins, which of the following is usually true? A)They open and close in response to protein signals. B)They change their conformation after binding with signal polypeptides. C)They are only attached to one membrane surface: exterior or interior. D)They preferentially bind with lipid or glycolipid signal molecules. E)They lead to changes in intracellular ion concentration. - B Since steroid receptors are located intracellularly, which of the following is true? A)The receptor molecules are themselves lipids or glycolipids. B)The steroid/receptor complex can cross the nuclear membrane. C)The receptor molecules are free to move in and out of most organelles. D)The unbound steroid receptors are quickly recycled by lysosomes. E)The concentration of steroid receptors must be relatively high in most cells. - B The receptors for a group of signaling molecules known as growth factors are often A)cyclic AMP. B)ligand-gated ion channels. C)neurotransmitters. D)receptor tyrosine kinases. E)G protein-coupled receptors. - D Binding of a signaling molecule to which type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane? A)phosphorylated receptor tyrosine kinase dimer B)ligand-gated ion channel C)G protein-coupled receptor D)intracellular receptor E)receptor tyrosine kinase - B

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    If an adult person has a faulty version of the human analog to ced-4 of the nematode, which of the following is most likely to result? A)activation of a developmental pathway found in the worm but not in humans B)webbing of fingers or toes C)a form of c ancer in which there is insufficient apoptosis D)neurodegeneration E)excess skin exfoliation - C A drug designed to inhibit the response of cells to testosterone would almost certainly result in which of the following? A)an increase in cytosolic calcium concentration B)an increase in receptor tyrosine kinase activity C)lower cytoplasmic levels of cAMP D)a decrease in G protein activity E)a decrease in transcriptional activity of certain genes - E Which of the following is a correct association? A)GTPase activity and hydrolysis of GTP to GDP B)adenylyl cyclase activity and the conversion of cAMP to AMP C)phosphorylase activity and the catabolism of glucose D)phosphodiesterase activity and the removal of phosphate groups E)kinase activity and the addition of a tyrosine - A An inhibitor of which of the following could be used to block the release of calcium from the endoplasmic reticulum? A)tyrosine kinases B)adenylyl cyclase C)serine/threonine kinases D)phosphodiesterase E)phospholipase C - E

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    Which of the following most likely would be an immediate result of growth factor binding to its receptor? A)protein kinase activity B)phosphorylase activity C)GTPase activity D)protein phosphatase E)adenylyl cyclas eactivity - A Pax-6 is a gene that is involved in eye formation in many invertebrates, such as Drosophila. Pax-6 is found as well in vertebrates. A Pax- 6 gene from a mouse can be expressed in a fly and the protein (PAX- 6) leads to a compound fly eye. This information suggests which of the following? A)PAX-6 proteins have identical amino acid sequences. B)Pax-6 genes are identical in nucleotide sequence. C)Pax-6 is highly conserved and shows shared evolutionary ancestry. D)PAX- 6 from a mouse can function in a fly, but a fly's Pax -6 gene cannot function in a mouse. E)PAX6 proteins are different for formation of different kinds of eyes. - C The major advantage of using artificial chromosomes such as YACs and BACs for cloning genes is that A)only one copy of a plasmid can be present in any given cell, whereas many copies of a YAC or BAC can coexist in a single cell. B)plasmids are unable to replicate in cells. C)YACs and BACs can carry much larger DNA fragments than ordinary plasmids can. D)YACs and BACs can be used to express proteins encoded by inserted genes, but plasmids cannot. E)All of these are correct. - C

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    A student wishes to clone a sequence of DNA of ~200 kb. Which vector would be appropriate? A)a BAC B)a plant virus C)a typical bacteriophage D)a large polypeptide E)a plasmid - A The DNA fragments making up a genomic library are generally contained in A)BACs. B)recombinant viral RNA. C)radioactive eukaryotic cells. D)DNA-RNA hybrids. E)individual wells. - A A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using A)a restriction enzyme to cut the gene into shorter pieces. B)DNA ligase to put together fragments of the DNA that code for a particular polypeptide. C)reverse transcriptase to reconstruct the gene from its mRNA. D)RNA polymerase to transcribe the gene. E)DNA polymerase to reconstruct the gene from its polypeptide product. - C In a cell-free system, what other components would you have to provide for this virus to express its genes? A)ribosomes, tRNAs, amino acids, and GTP B)bean cell enzymes C)RNA nucleotides and GTP D)RNA nucleotides, RNA polymerase, and GTP E)ribosomes, tRNAs and amino acids - A To cause a human pandemic, the H5N1 avian flu virus would have to

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    A)develop into a virus with a different host range. B)become capable of human-to-human transmission. C)spread to primates such as chimpanzees. D)become much more pathogenic. E)arise independently in chickens in North and South America. - B In the figur e, at the arrow marked II (pointing at viral DNA before its being reproduced), what enzyme(s) are being utilized? A)host cell RNA polymerase B)viral DNA polymerase C)host cell DNA and RNA polymerases D)reverse transcriptase E)host cell DNA polymerase - E Most molecular biologists think that viruses originated from fragments of cellular nucleic acid. Which of the following observations supports this theory? A)Viruses are enclosed in protein capsids rather than plasma membranes. B)Viral genomes are usually similar to the genome of the host cell. C)Viruses can infect both prokaryotic and eukaryotic cells. D)Viruses contain either DNA or RNA. E)Viruses can reproduce only inside host cells. - B Why do RNA viruses appear to have higher rates of mutation? A)RNA viruses can incorporate a variety of nonstandard bases. B)RNA viruses replicate faster. C)Replication of their genomes does not involve proofreading. D)RNA nucleotides are more unstable than DNA E)RNA viruses are more sensitive to mutagens. - C Most human-infecting viruses are maintained in the human population only. However, a zoonosis is a disease that is transmitted from other vertebrates to humans, at least sporadically, without requiring viral mutation. Which of the following is the best example of a zoonosis?

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    A)HIV B)rabies C)smallpox D)hepatitis virus E)herpesvirus - B By which of the following processes is insulin synthesized? A) transcription B) hydrolysis C) translation D) decarboxylation E) phosphorylation - C The subunits of insulin are A) monosaccharides B) nucleotides C) fatty acids D) amino acids E) phospholipids - D Following synthesis, the insulin polypeptide undergoes disulfide bond formation. This is an example of a ______________ that affects _____________. A) posttranslational process; primary structure B) posttranslational process; tertiary structure C) transcriptional process; primary structure D) posttranscriptional process; tertiary structure - B As a secreted protein, the route traveled by insulin to the outside of the pancreatic cells is A) rough ER → Golgi → plasma membrane B) Golgi → rough ER → plasma membrane C) Golgi → lysosomes → plasma membrane D) Golgi → smooth ER → plasma membrane E) rough ER → Golgi → lysosomes - A

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    The hormone epinephrine (also called adrenaline) is secreted from cells of the adrenal gland in response to a threatening or exciting condition. The hormone binds to G protein-coupled receptors on the plasma membrane of liver cells, stimulating the breakdown of glycogen, a polymer of glucose. The glucose diffuses out of the liver cells, is circulated in the bloodstream, and is subsequently taken up into muscle cells, where it is used in respiration. The ATP produced by respiration is used for muscle contraction, allowing the organism to run for safety in response to the threat. Use all of this information to answer the following four questions. 8) Once epinephrine binds to the liver cells, the signal transduction pathway occurs in the order epinephrine → G protein-coupled receptor → G protein → adenylyl cyclase → cAMP. Which of the following is the second messenger? A) G protein-coupled receptor B) G - E The hormone epinephrine (also called adrenaline) is secreted from cells of the adrenal gland in response to a threatening or exciting condition. The hormone binds to G protein-coupled receptors on the plasma membrane of liver cells, stimulating the breakdown of glycogen, a polymer of glucose. The glucose diffuses out of the liver cells, is circulated in the bloodstream, and is subsequently taken up into muscle cells, where it is used in respiration. The ATP produced by respiration is used for muscle contraction, allowing the organism to run for safety in response to the threat. Use all of this information to answer the following four questions.Glycogen is a __________ and is broken down to glucose by _________. A) polypeptide; dehydration B) protein; translation C) polysaccharide; hydrolysis D) lipid; decarboxylation

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    E) nucleic acid; denaturation - C The hormone epinephrine (also called adrenaline) is secreted from cells of the adrenal gland in response to a threatening or exciting condition. The hormone binds to G protein-coupled receptors on the plasma membrane of liver cells, stimulating the breakdown of glycogen, a polymer of glucose. The glucose diffuses out of the liver cells, is circulated in the bloodstream, and is subsequently taken up into muscle cells, where it is used in respiration. The ATP produced by respiration is used for muscle contraction, allowing the organism to run for safety in response to the threat. Use all of this information to answer the following four questions. Which of the following regarding glucose export from the liver cells into the bloodstream is true? A) It requires a membrane protein B) It occurs by osmosis C) It requires energy D) It occurs by active transportE) It is endergonic - A The hormone epinephrine (also called adrenaline) is secreted from cells of the adrenal gland in response to a threatening or exciting condition. The hormone binds to G protein-coupled receptors on the plasma membrane of liver cells, stimulating the breakdown of glycogen, a polymer of glucose. The glucose diffuses out of the liver cells, is circulated in the bloodstream, and is subsequently taken up into muscle cells, where it is used in respiration. The ATP produced by respiration is used for muscle contraction, allowing the organism to run for safety in response to the threat. Use all of this information to answer the following four questions. Following glucose uptake from the bloodstream, the muscele cells generate the ATP needed for muscle contraction through the process of respiration, which __________ glucose to ___________. A) oxidizes ... O2 B) oxidizes ... NADH

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    C) reduces ... CO2 D) oxidizes ... CO2 - D Based on the polarity of water molecules, the solute above is most likely A)hydrophobic. B)nonpolar. C)uncharged. D)a cation. E)an anion - D what is a hydroxyl group? - -OH Which of the following hydrocarbons has a double bond in its carbon skeleton? A)C2H4 B)C3H8 C)CH4 D)C2H6 E)C2H2 - A Answers may be used once, more than once, or not at all. A. applies to nucleic acids B. applies to proteins C. applies to polysaccharides D. applies to lipids E. applies to all macromolecules 4)synthesis involves dehydration reactions - E Answers may be used once, more than once, or not at all. A. applies to nucleic acids B. applies to proteins C. applies to polysaccharides D. applies to lipids E. applies to all macromolecules 5)monomers are linked in peptide bonds - B What is a functional group on it side chain that is likely to be ionized at the pH of the cell? - A

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    What is a functional group on it side chain that can contribute to tertiary structure by forming a coavlent bond? - D Which of the following occurs by hydrolysis? A)the breakdown of polypeptides to monosaccharides B)the synthesis of polysaccharides from monosaccharides C)the breakdown of nucleic acids to nucleotides D)the formation of peptide bonds E)the addition of a fatty acid to glycerol - C Which of the following involves the formation of hydrogen bonds? A)disulfide bridge formation in proteins B) α -helix formation in proteins C)interaction between carboxyl and amino groups in side chains of proteins D)interaction between fatty acid tails in phospholipid bilayers E)the attachment of an amino acid to a growing polypeptide chain - B Two DNA molecules have the following base pair compositions: A. ATGGTAA B. GGAACCC TACCATT CCTTGGG Which one would have to be heated to a higher temperature to completely separate the two strands? A) A B) B C) Neither; they would be completely separated at the same temperature - B Which of the following best describes the flow of genetic information in a eukaryotic cell? A)transcription in the nucleus → transport of mRNA to the cytosol → translation on ribosomes B)transport of mRNA to the cytosol → translation on ribosomes → transcription in the nucleus C)transport of mRNA to the cytosol → transcription in the nucleus → translation on ribosomes

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