MMSC490 Practice Exam 1|123 Questions with Verified Answers,100% CORRECT

MMSC490 Practice Exam 1|123 Questions with Verified Answers cytoplasmic organelles are: a. absent in prokaryotic cells and present in eukaryotic cells. b. present in both prokaryotic and eukaryotic cells. c. present in prokaryotic cells and absent in eukaryotic cells. d. absent in both prokaryotic and eukaryotic cells. - CORRECT ANSWER a. absent in prokaryotic cells and present in eukaryotic cells E. coli is a useful model system for molecular biology studies because: a. it has a small genome. b. it reproduces rapidly. c. mutants can easily be isolated from culture dishes. d. All of the above - CORRECT ANSWER d. all of the above Arabidopsis thaliana is a model organism for studying the molecular biology of: a. plants. b. fungi. c. fruit flies. d. vertebrates. - CORRECT ANSWER a. plants The diffraction limited resolving power of a standard light microscope is approximately: a. 0.2 mm. b. 0.2 µm. c. 0.2 nm. d. 2 Å. - CORRECT ANSWER b. 0.2 um A common use of green fluorescent protein (GFP) is to: a. label antibodies. b. visualize proteins in living cells. c. photobleach other fluorescent proteins. d. label DNA sequences. - CORRECT ANSWER b. visualize proteins in living cells Electron microscopes have a resolution advantage over light microscopes because: a. electron microscopes allow the viewer to examine living cells. b. electron microscope lens have a larger numerical aperture. c. electron microscopes are easier to use. d. the wavelength of electrons is shorter than that of light - CORRECT ANSWER d. the wavelength of electrons is shorter than that of light In a classic experiment that demonstrated the semiconservative nature of DNA replication, cells were grown first in 14N-containing media and later in 15N-containing media, and DNA was separated by: a. electrophoresis. b. differential centrifugation. c. velocity density-gradient centrifugation. d. equilibrium centrifugation. - CORRECT ANSWER d. equilibrium centrifugation The most abundant molecules in cells are: a. proteins. b. carbohydrates. c. lipids. d. water. - CORRECT ANSWER d. water. A few sugars joined together are called a(n): a. glycoside. b. oligosaccharide. c. polysaccharide. d. starch. - CORRECT ANSWER b. oligosaccharide Steroid hormones are derivatives of: a. cholesterol. b. phospholipids. c. amino acids. d. sugars. - CORRECT ANSWER a. cholesterol Complementary base pairs form _______ bonds to direct replication of DNA. a. hydrogen b. phosphodiester c. glycosidic d. covalent - CORRECT ANSWER a. hydrogen Polymerization of nucleotides to form nucleic acids involves the formation of _______ bonds. a. peptide b. phosphodiester c. glycosidic d. hydrogen - CORRECT ANSWER b. phosphodiester Serine, threonine, asparagine, and glutamine are all _______ amino acids. a. basic b. acidic c. polar d. nonpolar - CORRECT ANSWER c. polar In the primary structure of a protein, amino acids are joined together by _______ bonds. a. peptide b. phosphodiester c. glycosidic d. hydrophobic - CORRECT ANSWER a. peptide The interaction of the α and β subunits to form the hemoglobin molecule is an example of _______ structure. a. primary b. secondary c. tertiary d. quaternary - CORRECT ANSWER d. quaternary The unique properties of different membranes are primarily a function of their: a. proteins. b. phospholipids. c. cholesterol molecules. d. glycolipids. - CORRECT ANSWER a. proteins The role of double bonds in the fatty acid tails of membrane phospholipids is to: a. help stabilize the membrane. b. react with adjacent double bonds. c. increase membrane fluidity. d. interact with membrane proteins - CORRECT ANSWER c. increase membrane fluidity The currently accepted model of membrane structure is called the _______ model. a. lipid bilayer b. unit membrane c. lipid raft d. fluid mosaic - CORRECT ANSWER d. fluid mosaic Integral membrane proteins are those that: a. are directly associated with membrane lipids. b. are associated with the membrane indirectly. c. never span the membrane bilayer. d. None of the above - CORRECT ANSWER a. are directly associated with membrane lipids Membrane proteins can be anchored to the cytosolic face of the plasma membrane by: a. sugar groups of glycolipids. b. prenyl groups. c. sugar groups of glycoproteins. d. None of the above - CORRECT ANSWER b. prenyl groups Lipid bilayers are permeable only to molecules that are _______ and _______. a. large; uncharged b. large; charged c. small; uncharged d. small; charged - CORRECT ANSWER c. small; uncharged During formation of eggs and sperm, one member of each chromosome pair is transmitted to each progeny cell in a type of cell division called: a. mitosis. b. gametogenesis. c. cytokinesis. d. meiosis. - CORRECT ANSWER d. meiosis Eggs and sperm are: a. haploid. b. diploid. c. euploid. d. tetraploid. - CORRECT ANSWER a. haploid RNA molecules that serve as templates for protein synthesis are called _______ RNAs. a. messenger b. transfer c. ribosomal d. small nuclear - CORRECT ANSWER a. messenger Because the genetic code usually has more than one codon for each amino acid, the code is said to be: a. redundant. b. wobbly. c. a template. d. degenerate. - CORRECT ANSWER d. degenerate Reverse transcriptase is an enzyme that catalyzes _______ synthesis. a. DNA-directed RNA b. RNA-directed DNA c. DNA-directed DNA d. RNA-directed RNA - CORRECT ANSWER b. RNA-directed DNA To clone genes, a plasmid vector should contain a(n): a. origin of replication. b. restriction nuclease cut site. c. antibiotic resistance gene. d. All of the above - CORRECT ANSWER d. all of the above Nucleic acid hybridization is the: a. mating of two genetically different organisms. b. formation of hybrid nuclei when two cells are fused. c. formation of a double-stranded molecule from the interaction of two complementary-sequence single-stranded molecules. d. recombining of DNA molecules from two different organisms. - CORRECT ANSWER c. formation of a double-stranded molecule from the interaction of two complementary-sequence single-stranded molecules The technique by which fragments of DNA are separated by gel electrophoresis, denatured, blotted on nitrocellulose paper, labeled with a complementary radioactive probe, and detected by autoradiography is called _______ blotting. a. Southern b. Northern c. Western d. Eastern - CORRECT ANSWER a. Southern In 1995, the first complete genome of _______ was sequenced. a. Escherichia coli b. Saccharomyces cerevisae c. Haemophilus influenzae d. Caenorhabditis elegans - CORRECT ANSWER c. Haemophilus influenzae Analysis of the H. influenza and E. coli genomes revealed that _______% of the genomes encodes for protein. a. 25 b. 50 c. 75 d. 90 - CORRECT ANSWER d. 90 The feature that most clearly distinguishes eukaryotes from prokaryotes is the presence of _____ in eukaryotic cells. a. Ribosomes b. Oxidative phosphorylation c. RNA molecules d. Nucleus - CORRECT ANSWER d. nucleus Drosophila melanogaster was an organism of choice for the study of: a. The process of fertilization b. The process of cell aggregation to form a multicellular organism c. The process of development d. Mammalian genetics - CORRECT ANSWER c. the process of development Living cells are commonly visualized by means of _____ microscopy. a. Phase-contrast b. Bright-field c. Fluorescence d. Electron - CORRECT ANSWER a. phase-contrast Super resolution light microscopes extend the resolution limits of light microscopy to: a. 0.2 to 0.5 mm b. 0.2 to 0.5 um c. 20 to 100 nm d. 20 to 100 Å - CORRECT ANSWER c. 20 to 100 nm Which fish is proving to be a useful model organism in the study of vertebrate development? a. Zebrafish b. Goldfish c. Salmon d. Guppy - CORRECT ANSWER a. zebrafish The method by which cell components are separated by centrifugation at progressively higher speeds is called _____ centrifugation. a. Differential b. Velocity c. Density-gradient d. Equilibrium - CORRECT ANSWER a. differential Cultures grown from cells of a dissociated tissue are called: a. Transformed cell lines b. Normal cell lines c. Primary cell cultures d. Secondary cell cultures - CORRECT ANSWER c. primary cell cultures In polysaccharides, sugars are linked together by means of _____ bonds. a. Phosphodiester b. Peptide c. Glycosidic d. Hydrophobic - CORRECT ANSWER c. glycosidic The most common molecules in cellular membranes are the: a. Glycolipids b. Phospholipids c. Cholesterol molecules d. Protein - CORRECT ANSWER b. phospholipids Phospholipids in a membrane commonly a. Move laterally in the plane of the bilayer b. Rotate within the bilayer c. Move from one bilayer to the other d. Both a and b - CORRECT ANSWER d. both a and b Transmembrane proteins can span the lipid bilayer as a. Alpha helices b. Beta helices c. Random chains d. Both a and c - CORRECT ANSWER a. alpha helices Channels form pores through which molecules of appropriate size and charge can cross a membrane. By contrast, carrier molecules that traverse a membrane against their concentration gradient do so by _____ transport. a. Active b. Passive c. Carrier-mediated d. Channel-mediated - CORRECT ANSWER a. active Animal cells and most cells of higher plants are: a. Haploid b. Diploid c. Euploid d. Tetraploid - CORRECT ANSWER b. diploid DNA replicates: a. Conservatively b. Semi-conservatively c. Liberally d. By hybridization - CORRECT ANSWER b. semi-conservatively Which of the following deletions will not change the reading frame of a gene? a. One nucleotide b. Two nucleotides c. Three nucleotides d. Four nucleotides - CORRECT ANSWER c. three nucleotides Restriction endonucleases are enzymes that: a. Cleave DNA only at specific sequences b. Act only on the ends of DNA strands c. Act only in a single species of bacteria d. Cleave only nuclear DNA - CORRECT ANSWER a. cleave DNA only at specific sequences The most common method of DNA sequencing is based on premature termination of DNA synthesis by inclusion of: a. Dideoxynucleotides b. Endonuclease c. Ampicillin d. Puromycin - CORRECT ANSWER a. dideoxynucleotides The original cell was thought to have arisen from the enclosure of self-replicating _____ by a phospholipid membrane. a. DNA b. Carbohydrate c. Protein d. RNA - CORRECT ANSWER d. RNA The source of the atmospheric oxygen necessary for the development of oxidative metabolism is thought to have been: a. Glycolysis b. The formation of Earth c. Photosynthesis d. The breakdown of ATP - CORRECT ANSWER c. photosynthesis Chloroplasts are thought to have originated from endosymbiosis of _____ by a large host cell. a. Anaerobic bacteria b. Photosynthetic eubacteria such as cyanobacteria c. Fungi such as yeast d. Non-photosynthetic aerobic bacteria - CORRECT ANSWER b. photosythetic eubacteria such as cyanobacteria The genome of eukaryotes consists of genes derived from: a. Archaebacteria alone b. Bacteria alone c. Both archaebacteria and bacteria d. Neither archaebacteria nor bacteria - CORRECT ANSWER c. both archaebacteria and bacteria Which of the following is not a unicellular eukaryote? a. Saccharomyces cerevisiae b. Paramecium c. Archaebacteria d. Chlamydomonas - CORRECT ANSWER c. archaebacteria Solid tissues in animals include epithelial tissue, _______ tissue, nervous tissue, and muscle. a. Blood b. Connective c. Ground d. Epidermal - CORRECT ANSWER b. connective How many genes does an E. coli have? a. 4,300 b. 6,000 c. 14,000 d. 20,000-25,000 - CORRECT ANSWER a. 4,300 An E. coli cell under well-defined laboratory conditions divides about every: a. 20 minutes b. 2 hours c. 12 hours d. 24 hours - CORRECT ANSWER a. 20 minutes Which of the following are the most commonly used mammals for genetic studies? a. Humans b. Xenopus laevis c. Mice d. Cats - CORRECT ANSWER c. mice What is the theoretical diffraction limit of resolution of a light microscope used to look at a sample through oil? a. 0.22 micrometer b. 0.2 nm c. 1 mm d. 0.305 micrometer - CORRECT ANSWER a. 0.22 um In fluorescence microscopy, the immediate source of the light detected is light that has been _____ the sample. a. Absorbed by b. Emitted by c. Exciting d. Scattered from - CORRECT ANSWER b. emitted by Which of the following is a high-resolution light microscope technique for detecting interactions between proteins? a. FRAP (fluorescence recovery after photobleaching) b. FRET (fluorescence resonance energy transfer) c. MPEM (multi-photon excitation microscopy) d. Confocal microscopy - CORRECT ANSWER b. FRET (fluorescence resonance energy transfer) Transmission electron microscopy is used to: a. Study in single, thin sections the shapes of whole cells b. View living cells in three dimensions c. View fluorescently labeled proteins in cells d. Observe subcellular organelles and macromolecules - CORRECT ANSWER d. observe subcellular organelles and macromolecules What is the smallest number of ultracentrifugation steps needed to separate nuclei from ribosomes in a cellular lysate? a. 1 b. 2 c. 4 d. 7 - CORRECT ANSWER a. 1 Embryonic stem cells are different from primary cell cultures or permanent cell lines derived from a tissue in that they are capable of: a. Generating many cell types b. Growing and dividing c. Synthesizing their own DNA d. Transporting nutrients across their plasma membrane - CORRECT ANSWER a. generating many cell types In contrast to animal cells, yeast or bacterial cell cultures can be grown on fairly simple media without the need to add amino acids or various vitamins and hormones. This is primarily because animal cells: a. Typically live in association with other cells b. Are less capable of transporting small molecules across their membranes c. Come from organisms that have specialized cell types d. Have too many genes to be able to keep track of the biosynthesis of needed metabolites - CORRECT ANSWER c. come from organisms that have specialized cell types Approximately how many doublings can normal human fibroblasts undergo in culture? a. 5 b. 50 to 100 c. They will go on proliferating indefinitely d. They will not double at all but dispersing them in culture allows them to be studied in isolating from other cell types - CORRECT ANSWER b. 50 to 100 Bacteriophages are: a. A stain of gram-negative bacteria b. Bacteria that phagocytose other competing bacteria c. Bacterial lysosomes d. Viruses that infect bacteria - CORRECT ANSWER d. viruses that infect bacteria Which of the following is not one of the four major classes or organic molecules in the cell? a. Carbohydrates b. Lipids c. Water d. Proteins - CORRECT ANSWER c. water What is the major carbohydrate-storage molecule in plants? a. Starch b. Cellulose c. Glycogen d. Deoxyribonucleic acid - CORRECT ANSWER a. starch Introducing a double bond into a fatty acid has the effect of putting a(n) _____ into the conformation of the molecule. a. Amino acid bulge b. Kink c. Reverse spiral d. Reinforcing rod - CORRECT ANSWER b. kink Phospholipids consist of a 3-carbon core to which fatty acids and a phosphate group are linked. The most common 3-carbon core is: a. Dihydroxyacetone b. Glyceraldehyde c. Glycerol d. Serine - CORRECT ANSWER c. glycerol Molecules that are partly water-soluble and partly water-insoluble are: a. Hydrophilic b. Amphipathic c. Hydrophobic d. Allosteric - CORRECT ANSWER b. amphipathic Cholesterol, a membrane lipid in animals, has a chemical structure similar to: a. Estradiol b. Phosphatidylinositol c. Thymine d. Triacylglycerol - CORRECT ANSWER a. estradiol Which of the following bases is not found in DNA? a. Adenine b. Cytosine c. Thymine d. Uracil - CORRECT ANSWER d. uracil How many common amino acids are there? a. 5 b. 10 c. 20 d. 25 - CORRECT ANSWER c. 20 A disulfide bond is formed between ____ residues. a. Cysteine b. Glycine c. Methionine d. Tyrosine - CORRECT ANSWER a. cysteine Which of the following classes of amino acids is buried within the folded structure of the protein? a. Acidic b. Basic c. Nonpolar d. Polar - CORRECT ANSWER c. nonpolar The three-dimensional structure of a protein is analyzed most definitively by: a. Electron microscopy b. Light microscopy c. Subcellular fractionation d. X-ray crystallography - CORRECT ANSWER d. x-ray crystallography The alpha helix is an example of which level of protein structure? a. Primary b. Quaternary c. Secondary d. Tertiary - CORRECT ANSWER c. secondary Proteins must have more than one _____ to have a quaternary structure. a. Alpha helix b. Beta sheet c. Polypeptide chain d. Transmembrane segment - CORRECT ANSWER c. polypeptide chain Enzymes act by: a. Lowering the overall change in the free energy of a reaction b. Decreasing the distance that reactants must diffuse to find one another c. Increasing the activation energy d. Decreasing the activation energy - CORRECT ANSWER d. decreasing the activation energy Enzymes affect the transition state of a chemical reaction by: a. Binding to the substrate(s) b. Providing a surface on which the reactions converting substrate to product can occur more rapidly c. Altering the conformation of the substrate(s) to approach that of the transition state d. All three answer choices - CORRECT ANSWER d. all three answer choices The lock-and-key and induced-fit models are two alternative models that can explain how enzymes and substrates interact. These two models can be distinguished from each other according to changes in the: a. Viscosity of the reaction solution as the substrate and enzyme bind b. Shape as the substrate and enzyme bind c. Reaction solution temperature as a result of the endothermic cooling that occurs during substrate binding d. Reaction solution color as the substrate and enzyme bind - CORRECT ANSWER b. shape as the substrate and enzyme bind Chymotrypsin, trypsin, elastase, and thrombin are all grouped together as members of the serine protease family because each: a. Has similar charge and shape properties in its substrate insertion pockets b. Can form a heptahedral complex with its substrate c. Uses the same catalytic mechanisms involving the same key amino acids d. Can be modified by the cell wall biosynthetic degradative enzyme chitinase - CORRECT ANSWER c. uses the same catalytic mechanisms involving the same key amino acids Which of the following is not true of coenzymes? a. Chemically, they are branched amino acids b. They serve as carriers of several types of chemical groups c. They transfer specific chemical groups among a wide range of substrates d. They work together with enzymes to enhance chemical reactions without being irreversibly altered - CORRECT ANSWER a. chemically, they are branched amino acids Coenzymes are chemically related to: a. Amino acids b. Inorganic phosphate c. Glucose d. Vitamins - CORRECT ANSWER d. vitamins All of the following are ways in which enzyme activity can be regulated except: a. By binding to an allosteric site b. Through feedback inhibition c. By modulation of intracellular sucrose concentrations d. Through phosphorylation - CORRECT ANSWER c. by modulation of intracellular sucrose concentrations About 50% of the mass of most biological membranes consists of lipids and about 50% consists of proteins. Therefore: a. The membranes contain fewer molecules of lipid than of protein b. The membranes contain equal number of lipid and protein molecules c. The membranes contain more molecules of lipid than of protein d. Only a few membrane proteins are exposed at the cell surface - CORRECT ANSWER c. the membranes contain more molecules of lipid than of protein Lipids with unsaturated fatty acids: a. Decrease the fluidity of membranes b. Increase the charge associated with the inner face of a membrane c. Increase the fluidity of membranes d. Are present only on the inner side of the plasma membrane - CORRECT ANSWER c. increase the fluidity of membranes In the fluid mosaic model of biological membrane structure, transmembrane proteins are: a. Embedded nearly randomly in the lipid bilayer b. Almost completely surrounded by membrane lipid c. Segregated into large protein clusters or rafts d. Weakly held in place on the surface of the lipid bilayer - CORRECT ANSWER a. embedded nearly randomly in the lipid bilayer What is the effect of a beta barrel on the permeability of a membrane? a. It decreases permeability b. It increases permeability c. It has no effect d. Beta barrels are never found in membranes - CORRECT ANSWER b. it increases permeability Transport across biological membranes is speeded by what class of biological molecules? a. Carbohydrates b. Lipids c. Nucleic acids d. Proteins - CORRECT ANSWER d. proteins Whereas small uncharged molecules can diffuse through the hydrophobic core of a phospholipid bilayer, a larger polar substance such as glucose must enter cells by binding to: a. A non-phospholipid such as cholesterol b. The carbohydrate portion of glycolipids c. Peripheral membrane proteins located on the inner side of the membrane d. Carrier proteins that facilitate the passage of specific molecules across membranes - CORRECT ANSWER d. carrier proteins that facilitate the passage of specific molecules across membranes Passive transport across a membrane refers to: a. Transport into the interior of a cell b. Transport out of a cell c. Transport in the energetically favorable direction d. Simple diffusion across membranes, without the help of proteins such as channels or carriers - CORRECT ANSWER c. transport in the energetically favorable direction Which of the following correctly represents the distinction between the terms, "genotype" and "phenotype"? a. The genotype is the genetic composition of an organism, whereas the phenotype is its physical appearance. b. Phenotype is the genetic composition of an organism, while genotype is the physical appearance. c. There is no difference between a genotype and a phenotype. d. A phenotype is dominant, and a genotype is recessive - CORRECT ANSWER a. the genotype is the genetic composition of an organism, whereas the phenotype is its physical appearance In Gregor Mendel's experiments on pea genetics, he determined that yellow seed color, Y, was dominant over green seed color, y. In a cross between two plants, one with yellow seeds and the other with green seeds, all the seeds produced from the offspring were yellow. What was the genotype of the parent plant with yellow seeds? a. Yy b. yY c. YY d. yy - CORRECT ANSWER c. YY The two strands of DNA in the double helix are held together by: a. Covalent bonds between the bases of each strand b. Hydrogen bonds between the bases of each strand c. Interactions between the sugar residues of each chain d. Interactions between phosphate residues of each strand - CORRECT ANSWER b. hydrogen bonds between the bases of each strand Which of the following serves as an adapter between amino acids and mRNA during translation? a. tRNA b. rRNA c. DNA d. siRNA - CORRECT ANSWER a. tRNA The enzyme that synthesizes DNA using RNA templates is called: a. DNA polymerase b. RNA polymerase c. Reverse transcriptase d. Ribozymes - CORRECT ANSWER c. reverse transcriptase The characterization of restriction endonucleases was a key step in the development of recombinant DNA technology. What is the function of these enzymes? a. Synthesis of complementary strands of DNA from a DNA template b. Ligation of two digested DNA strands c. Synthesis of RNA from a DNA template d. Cleavage of DNA at specific sequences - CORRECT ANSWER d. cleavage of DNA at specific sequences A restriction enzyme with a four-base recognition site would cleave DNA with a statistical frequency of once every: a. 4 base pairs b. 4,096 base pairs c. 256 base pairs d. 65.5 kilobases - CORRECT ANSWER c. 256 base pairs Which of the following correctly describes a cDNA molecule? a. A DNA copy of an RNA sequence synthesized by the enzyme reverse transcriptase b. The nucleic acid portion of a ribosome c. RNA or single-stranded DNA complementary to the mRNA of a gene of interest that hybridizes with the mRNA and blocks its translation d. A DNA molecule capable of independent replication in a host cell - CORRECT ANSWER a. a DNA copy of an RNA sequence synthesized by the enzyme reverse transcriptase How many molecules would be produced from two molecules of DNA following five rounds of PCR amplification? a. 64 b. One billion c. 10 d. 32 - CORRECT ANSWER a. 64 What technique would you use to determine if the level of a specific mRNA had been increased in response to an inducer? a. Western blotting b. Southern blotting c. Immunoprecipitation d. Northern blotting - CORRECT ANSWER d. Northern blotting Which of the following terms refers to a collection of clones that contain all the genomic or mRNA sequences of a particular cell type? a. DNA microarray b. Recombinant DNA library c. Yeast two-hybrid system d. Expression vector - CORRECT ANSWER b. recombinant DNA library The SDS in SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of a protein is used to: a. Neutralize the charge of a protein so that charge is not a factor in its rate of migration. b. Cross-link the protein's structure so that it does not become denatured during electrophoresis. c. Digest the protein into smaller fragments that are more easily separated by electrophoresis. d. Denature the protein and give it an overall negative charge. - CORRECT ANSWER d. denature the protein and give it an overall negative charge Transgenic mice carry a foreign gene: a. In some cells (both germ line and somatic) but not in others - transgenic mice are chimeras b. Only in their germ line cells c. Only in their somatic cells d. In all of their cells - CORRECT ANSWER d. in all of their cells The CRISPR/Cas system is a fast and powerful method to introduce specific mutations into cellular genomes via homologous recombination to study the function of genes and the proteins they encode. Which of the following are necessary reagents for CRISPR/Cas? a. Mutant copy of target gene, guide RNA, and Cas9 b. Antisense RNA complementary to target gene, Cas9 c. Antibody to DNA nuclease, Cas9 d. siRNA complementary to the target mRNA, Cas9 - CORRECT ANSWER a. mutant copy of target gene, guide RNA, and Cas9 Which of the following correctly outlines the process of RNA interference, beginning with a double-stranded RNA molecule? a. Reverse transcription of RNA to cDNA; addition of oligonucleotide linkers containing restriction endonuclease cleavage sites; cDNA ligation to appropriate vector; introduction of recombinant molecule into E. coli b. Cleavage by Dicer; association with RISC; unwinding of siRNA; pairing with target mRNA; mRNA cleavage c. Unwinding of siRNA; cleavage by Dicer; association with RISC; pairing with target mRNA; mRNA cleavage d. Reverse transcription of RNA to cDNA; double-stranded DNA heated to separate strands; cooling to allow primers to bind to each strand of DNA; synthesis of new DNA molecules by Taq polymerase - CORRECT ANSWER b. cleavage by Dicer; association with RISC; unwinding of siRNA; pairing with target mRNA; mRNA cleavage Which of the following organisms has the highest percentage of its genome used to encode protein? a. Drosophila melanogaster b. Caenorhabdittis elegans c. Haemophilus influenza d. Saccharomyces cerevisiae - CORRECT ANSWER c. Haemophilus influenza The main difference between the genomes of the bacteria Haemophilus influenzae and E. coli is that: a. The genome of E. coli is approximately three times the size of the H. influenzae genome. b. The H. influenzae genome encodes a larger number of genes. c. The genome of H. influenzae is a circular molecule and that of E. coli is linear d. A higher percentage of the genome of H. influenzae contains genes encoding proteins. - CORRECT ANSWER a. the genome of E. coli is approximately three times the size of the H. influenzae genome An estimated 40% of the human genome contains proteins related to proteins that are also present in a diverse number of other species. These proteins are involved in which of the following cellular processes? a. Replication b. Transcription c. Translation d. All of the above - CORRECT ANSWER d. all of the above Neandertals are thought to be our closest evolutionary relatives, having diverged from humans 300,000 to 400,000 years ago, and their genome has been sequenced. Which of the following statements about humans and Neandertals is false? a. The coding sequences of only 90 genes in Neandertals are different from those of modern humans. b. Neandertal and chimpanzee genomes share about 99% identity. c. The genomes of modern humans and Neandertals are 99.9% identical. d. The Neandertal genome was surprisingly GC-rich. - CORRECT ANSWER d. the Neandertal genome was surprisingly GC-rich Which of the following is the first step in next-generation sequencing? a. Adapters are added to the ends of the DNA sample to allow amplification by PCR. b. The DNA sample is fragmented into smaller pieces. c. Sample DNA is filtered by electrophoresis to ensure uniform lengths. d. Amplification of the DNA sample by polymerase chain reaction (PCR). - CORRECT ANSWER b. the DNA sample is fragmented into smaller pieces Which of the following methods can accurately quantify the amount of mRNA expressed in a given cell or tissue sample? a. Immunoprecipitation and mass spectrometry b. RNAi and CRISPR/Cas c. Next-generation sequencing and tandem mass spectrometry d. DNA microarray and RNA-seq - CORRECT ANSWER d. DNA microarray and RNA-seq Which of the following molecular biology methods would best be used to directly determine the relative level of all mRNAs in a given cell or tissue? a. Two-dimensional gel electrophoresis b. Mass spectrometry c. DNA microarray d. Immunoprecipitation - CORRECT ANSWER c. DNA microarray A collection of all the RNAs that are expressed at any given time in a cell are referred to as the: a. Proteome b. Genome c. Metabolome d. Transcriptome - CORRECT ANSWER d. transcriptome All of the following are methods that allow scientists to investigate protein-protein interactions. Which method utilizes gene expression as the detection component? a. Mass spectrometry b. Yeast two-hybrid c. Tandem mass spectrometry d. Immunoprecipitation - CORRECT ANSWER b. yeast two-hybrid Two-dimensional gel electrophoresis is not an acceptable method to protein-protein interactions. Which of the following statements best describe the reason why? a. When the gel is stained there would be no way to determine if it is one or multiple proteins. b. The pH gradient in the first dimension would separate them. c. All proteins of a given charge and size will be identified together. d. The SDS-PAGE gel denatures all the proteins, preventing any quaternary interactions. - CORRECT ANSWER d. the SDS-PAGE gel denatures all the proteins, preventing any quaternary interactions Which of the following methods would best be used to determine posttranslational modifications to a protein, such as phosphorylation? a. Tandem mass spectrometry b. Mass spectrometry c. Immunoprecipitation d. Two-dimensional gel electrophoresis - CORRECT ANSWER a. tandem mass spectrometry Bioinformatics is: a. The systematic inactivation of each gene in the genome by homologous recombination. b. An electronic copy of genomic sequences that is exchanged between scientists across the world. c. A field of biology that is focused on developing the computational methods to analyze and extract useful biological information from the sequences of DNA. d. A quantitative understanding of integrated dynamic behavior of complex biological systems and processes. - CORRECT ANSWER c. a field of biology that is focused on developing the computational methods to analyze and extract useful biological information from the sequences of DNA The eukaryote Caenorhabditis elegans has been used especially in the study of: a. Animal development b. Immunology c. Photosynthesis d. Flagellar movement - CORRECT ANSWER a. animal development In exerting its biological activity on cells, epinephrine binds to a cell surface receptor, which activates a G protein, which then sequentially activates cAMP-dependent protein kinase, then phosphorylase kinase, then glycogen synthase, which then breaks down glucose. This is an example of: a. A network b. A feedback loop c. A signaling pathway d. Crosstalk - CORRECT ANSWER c. a signaling pathway In exerting its biological activity on cells, epinephrine binds to a cell surface receptor, which activates a G protein, which then sequentially activates cAMP-dependent protein kinase, then phosphorylase kinase, then glycogen synthase, which then breaks down glucose. In this example, epinephrine acts to break down glucose by stimulating glycogen synthase through activating five different proteins. Experimentally, you discover that in addition to stimulating the G protein, the epinephrine receptor can also directly stimulate glycogen synthase, bypassing the intermediate proteins. This would be an example of: a. Crosstalk b. A network c. Positive feedback d. A feedforward relay - CORRECT ANSWER ???