Download Microbiology Concepts and Applications and more Exams Biology in PDF only on Docsity!
BMS 503 Final Actual Exam Questions and
Answers
Anabolism is: a. all of the biochemical reactions taking place in an organism b. all of the energy releasing biochemical reactions in an organism c. all of the biochemical reactions in an organism that use cellular energy d. the maintenance pH at the neutral level preferred by most microorganisms - Solution c. all of the biochemical reactions in an organism that use cellular energy A bacterium that uses glucose as an energy source has been isolated from an anaerobic environment. After growth of the bacterium in an anaerobic culture, Dr. Strummer observes the bacterium producing hydrogen sulfide gas (H2S) and water. The pH of the media does not change. Which of the following processes in the bacteria utilizing? a. aerobic respiration b. anaerobic respiration c. fermentation d. sporulation - Solution b. anaerobic respiration Pasteur's Experiments with Swan Neck Flasks disproved which of the following theories on the origin of microorganisms: a. creationism b. spontaneous generation c. evolution d. clay theory - Solution b. spontaneous generation Which of the following is true about the Citric Acid Cycle: a. the citric acid cycle successfully catabolizes glucose generating 4 ATP and 2 acetyl-CoA b. the citric acid cycle utilizes 2 acetyl-CoA molecules to produce 3 NADH and 1 FADH c. the citric acid cycle utilizes 2 acetyl-CoA molecules to produce 6 NADH and 2 FADH d. the citric acid cycle utilizes 10 NADH and 2 FADH2 to generate 28 ATP - Solution c. the citric acid cycle utilizes 2 acetyl-CoA molecules to produce 6 NADH and 2 FAD
Compared to Eukaryotes, Bacteria and Archaea have _____ surface-area- to-volume ratios, causing ________ nutrient exchange and growth rates. A. lower, slower B. lower, faster C. higher, slower D. higher, faster - Solution D. higher, faster Eosin Methylene Blue Agar (EMB agar) contains eosin, methylene blue, and bile salts. These chemicals inhibit the growth of most bacteria except Escherichia coli and Salmonella typhimurium. EMB agar is an example of: a. differential media b. selective media c. synthetic media d. discrimiatory media - Solution b. selective media Sulfonamide is an antimicrobial drug that binds the bacterial enzyme dihydroperoate synthetase at its active site. This binding event inhibits the ability of dihydroperoate synthetase to bind its normal substrate PABA, inhibiting the production of Folic Acid. Sulfonamide is an example of a: a. competitive inhibitor b. non-competitive inhibitor c. feedback inhibitor d. negative regulator or repressor - Solution a. competitive inhibitor Which of the following is utilized during Anaerobic Respiration? a. glycolysis b. the citric acid cycle c. the electron transport chain d. all of the above - Solution d. all of the above Which one of the following is NOT utilized in both aerobic respiration and fermentation? a. glucose b. NAD+ c. FADH d. ATP - Solution c. FADH You are given an electron micrograph of a bacterial cell. In the micrograph you can clearly see three thin layers of different densities surrounding the
You have discovered a new coccoid-shaped (spherical-shaped) microorganism with no nucleus, a rigid cell wall, and a diameter of 2 um. The new microorganism is A. most likely a prokaryote B. most likely a eukaryote C. most likely a virus D. either a prokaryote or eukaryote - Solution A. most likely a prokaryote Which of the following best describes synthetic media: A. a media that contains chemicals to indicate bacterial species that possess or lack a biochemical process B. a complex media whose exact chemical composition is unknown C. a media that contains ingredients to inhibit growth of certain bacterial species, but allow the growth of others D. a media whose exact chemical composition is known - Solution D. a media whose exact chemical composition is known Which of the following is TRUE about gram-negative bacteria? A. gram-negative bacteria have an inner membrane and an outer membrane B. gram-negative bacteria stain purple when Gram stained C. gram-negative bacteria have a thick peptidoglycan cell wall that includes Lipotechoic acids (LTA) D. the inner membrane of gram-negative bacteria contains lipopolysaccharide (LPS) - Solution A. gram-negative bacteria have an inner membrane and an outer membrane SGLT1 is an integral membrane protein found in intestinal cells. It transports both sodium ions (Na+) and glucose from the lumen of the intestine across the cell membrane into the cytoplasm of the intestinal cells. SGLT1 is an example of a: A. uniporter b. antiporter c. cotransporter d. symporter - Solution d. symporter The cell wall of bacteria is made up of: A. chains of N-acetylglucosamine and N-acetylmuramic acid.
B. chains of N-acetylglucosamine and N-acetylmuramic acid linked by peptide crosslinks. C. chains of N-acetylglucosamine and N-acetylmuramic acid linked by lipid crosslinks. D. chains of N-acetylglucosamine and N-acetylmuramic acid linked by carbohydrate crosslinks. - Solution B. chains of N-acetylglucosamine and N-acetylmuramic acid linked by peptide crosslinks. Flagella are: A. protein filaments that allow for attachment of bacteria to a surface B. protein filaments that rotate allowing bacteria to move C. proteins that help compact the nucleoid of bacteria D. pentacyclic chemicals that stabilize the membranes of bacteria - Solution B. protein filaments that rotate allowing bacteria to move Fatty acids are biosynthesized using _________ carbon molecules along with the help of ___________ A. two, acyl carrier proteins B. two, lipase C. four, acyl carrier proteins D. four, lysozyme - Solution A. two, acyl carrier proteins Which of the following is TRUE about endospores: A. endospores are metabolically dormant forms of bacteria B. all bacteria can make endospores C. endospores are easily destroyed by washing surfaces with ethanol D. the process of forming an endospore is faster than the normal process of cell growth and division - Solution A. endospores are metabolically dormant forms of bacteria Using phase contrast microscopy on a wet mount of live cells, you observe motile bacilli moving rapidly through the field of view, changing directions after a brief tumble and taking off in a different direction. These cells are exhibiting: A. twitching motility, due to the action of pili. B. swimming motility, due to the action of flagella C. gliding motility, due to the action of fimbrae D. creeping motility, due to the presence of water - Solution B. swimming motility, due to the action of flagella
A. break down to release metal ions B. increase the rate of chemical reactions C. raise the ionic strength of water solution D. retain the pH at the neutral level preferred by most microorganisms - Solution B. increase the rate of chemical reactions Which of the following is TRUE about glycolysis: A. glycolysis catabolizes glucose generative 4 ATP and 2 acetyl-CoA B. glycolysis is utilized during fermentation, aerobic respiration and anaerobic respiration C. glycolysis requires 2 NADH and generates 2 ATP, for each glucose molecule catabolized D. the co-enzyme FAD+ is required for glycolysis - Solution B. glycolysis is utilized during fermentation, aerobic respiration and anaerobic respiration Which of the following metabolic pathways provides precursors (in the form of carbon skeletons) for the production of amino acids? A. glycolysis B. citric acid cycle C. the electron transport chain D. A and B E. B and C - Solution D. A and B (A. glycolysis B. citric acid cycle) Which of the following metabolic pathways generates ATP through oxidative phosphorylation? A. glycolysis B. citric acid cycle C. electron transport system D. fermentation - Solution C. electron transport system Which of the following macromolecules is NOT an important component of bacterial cell membranes? A. phospholipids b. proteins c. hoponoids d. cholesterol - Solution d. cholesterol Cells are mostly ___________ by dry weight
A. carbon B. nitrogen C. phosphorus D. oxygen - Solution A. carbon Which of the following metabolic pathways generates ATP by substrate- level phosphorylation of ADP? A. glycolysis B. citric acid cycle C. electron transport system D. A and B E. B and C - Solution D. A and B (A. glycolysis, citric acid cycle) True or False: Different bacterial species can often be distinguished by their colony morphology on solid agar media - Solution True True or False: if a chemical is reduced in a chemical reaction that chemical gains electrons - Solution True When examining the evolution of life on Earth, scientists find the eukaryotes are more similar to the kingdom _________ at the genetic level A. bacteria B. algae C. archaea D. yeast - Solution C. archaea Dr. Strummer has been asked to culture a newly discovered bacterium wth unknown nutritional requirements. Which type of media should Dr. Strummer use to ensure growth of the unknown bacteria? A. complex media B. defined media C. selective media D. differential media - Solution A. complex media In aerobic respiration, the final electron acceptor is A. hydrogen B. oxygen C. water D. ATP - Solution B. oxygen
B. the regulation of cell motility in response to an attractant or repellant C. the regulation of gene expression in response to fluctuations in cell- population density D. the regulation of gene expression through the use of small regulatory RNAs. - Solution C. the regulation of gene expression in response to fluctuations in cell-population density The lac operon is an example of a: A. monocistronic operon B. polycistronic operon C. unicistronic operon D. multicistronic operon - Solution B. polycistronic operon True or False: DNA replication requires PriA also known as primase to create an RNA primer for DNA synthesis - Solution True Cyclic AMP is synthesized from ATP by an enzyme called ___________ and plays a role in ____________________ - Solution adenylate cyclase, catabolite repression During DNA replication Okazaki fragments of the lagging strand are processed by: A. RNAse H removes RNA primers and DNA Polymerase III synthesizes DNA to fill the gaps and connect DNA fragments. B. RNAse H removes RNA primers, DNA Polymerase I synthesizes DNA to fill the gaps and connect DNA fragments. C. RNAse H removes RNA primers, DNA Polymerase I synthesizes DNA to fill the gaps and DNA ligase connects the DNA fragments D. DnaA removes RNA primers, DNA Pol III synthesizes DNA to fill the gaps and connect the DNA fragments - Solution C. RNAse H removes RNA primers, DNA Polymerase I synthesizes DNA to fill the gaps and DNA ligase connects the DNA fragments True or False: DNA replication is conservative, meaning that the template DNA is copied to produce a new double-stranded DNA product where each strand of DNA is completely new. - Solution False What is the role of DnaA during bacterial chromosome replication: A. binding and polymerization of DnaA allows DNA strand separation at oriC initiating DNA replication.
B. synthesis of the lagging strand of DNA during DNA replication C. removal of RNA primers from the lagging strand Okazaki fragments D. None of the above. DnaA is NOT involved in Dna replication, it is involved in transcription - Solution A. binding and polymerization of DnaA allows DNA strand separation at oriC initiating DNA replication. Which one of the following factors is NOT required for transcription: A. Beta-subunit of RNA polymerase B. sigmas factor of RNA polymerase C. A,G,C,U D. Rho - Solution D. Rho -- can be Rho independent termination Dr. Strummer experimentally changes the DNA sequence directly upstream of a translation start codon of genY in E.coli to investigate the function of the region of DNA. Experiments reveal that after the change the same amount of genY mRNA is made from the operon, but there are very little GenY protein made. What is the most likely function of the DNA sequence you changed? A. the DNA sequence likely functions as a promoter B. The DNA sequence likely functions as a ribosome-binding site. C. The DNA sequence likely functions as a translation termination sequence D. The DNA sequence likely functions as an operator sequence - Solution B. The DNA sequence likely functions as a ribosome-binding site. Tus and ter sites are involved in which cellular process: A. translation B. DNA replication C. transcription D. chemotaxis - Solution B. DNA replication What is the role of the sigmas factor of RNA polymerase? A. interact with transcription regulation proteins B. catalyze the joining of ribonucleic acids C. recognize the promoter of a gene D. catalyze the joining of amino acids to form a peptide - Solution C. recognize the promoter of a gene
A. rRNA in the ribosome facilitates the creation of a peptide bond between amino acids B. By mass, the ribosome is composed mostly of rRNA C. the ribosome is composed of two subunits, 50S and 30S that bind each other to form the complete ribosome before binding mRNA for translation D. the ribosome has three binding sites for tRNA - Solution C. the ribosome is composed of two subunits, 50S and 30S that bind each other to form the complete ribosome before binding mRNA for translation Dr. Strummer is working w/ rod-shaped bacteria. He makes a genetic mutation in the mreB gene that causes the cell to no longer produce mreB. Which of the following statements about this mutation is TRUE? A. this mutation would result in cell death B. this mutation would have no effect on cell shape C. this mutation would cause a rod shaped cell to take the shape of a coccus D. this mutation would cause a rod shaped cell to be amorphous, or without shape - Solution C. this mutation would cause a rod shaped cell to take the shape of a coccus By controlling the concentration of nutrients added into a chemostat continuously, cells can constantly be maintained at A. lag phase B. stationary phase C. exponential (log) or stationary phase D. death growth phase - Solution C. exponential (log) or stationary phase lacO is: A. a protein that negatively regulates the expression of the lactose operon B. A gene coding for a protein that negatively regulates the expression of the arabinose operon C. a sequence of DNA in the lactose operon promoter D. a gene that codes for a protein that both + and - regulates expression of arabinose operon - Solution C. a sequence of DNA in the lactose operon promoter True or False: thermophiles are bacteria that grow best at a medium temperature range of 10-45 degrees C, and include most human pathogens - Solution False --> these are mesophiles
In response to an external signal the sensor kinase of a two-component signal transduction system: A. phosphorylates itself and then phosphorylates a response regulator B. phosphorylates itself and then interacts with the promoter of an operon C. phosphorylates a response regulator D. phosphorylates the promoter of an operon - Solution A. phosphorylates itself and then phosphorylates a response regulator Dr. Strummer is investigating a new strain Vibrio cholera that is unable to make cholera toxin. DNA sequencing of this new strain reveals a mutation in the toxR gene that results in a non-functional ToxR protein. This strain is unable to produce high levels of cholera toxin because: A. It lacks the ability to sense the environmental signal that triggers the expression of the cholera toxin genes B. It lacks the ability to positively regulate expression of the toxT gene C. It lacks the ability to negatively regulate the expression of the toxT gene. D. It lacks the direct positive regulator of the ctxAB genes - Solution B. It lacks the ability to positively regulate expression of the toxT gene Dr. Strummer is working with a laboratory strain of E.coli that has a mutation in the lacI gene and thus does not produce functional LacI protein. Which of the following statements about this strain is correct: A. This strain will express the lactose operon when cultured in medium with high concentrations of glucose and lactose. B. This strain will express the lactose operon when cultured in medium with low concentrations of glucose and lactose. C. This strain will express the lactose operon when cultured in low glucose and expression is not dependent on the concentration of lactose in the culture medium. D. This strain is lactose intolerant. - Solution C. This strain will express the lactose operon when cultured in low glucose and expression is not dependent on the concentration of lactose in the culture medium. Chromosome replication in bacteria does NOT require which of the following: A. DNA polymerase I B. DNA polymerase III C. RNA polymerase D. DnaA - Solution C. RNA polymerase
D. death phase - Solution C. stationary phase --> viable cells @ peak Dr. Strummer is investigating a strain of E.coli that is unable to grow at temperatures about 37*C. He observes that this strain of bacteria is unable to express any of the genes that code for heat shock proteins that help E.coli deal with high temperature stress. What is the most likely explanation? A. the bacteria lacks a heat shock response B. the bacteria has a mutation in the positive regulator required for high level heat shock gene expression C. the bacteria has a mutation in the negative regulator required for high level heat shock gene expression D. the bacteria has a mutation in the sigma factor used for transcription of the heat shock genes - Solution D. the bacteria has a mutation in the sigma factor used for transcription of the heat shock genes The EnvZ-OmpR system in E.cooli allows the bacteria to sense changes in osmolarity in the environment and change its gene expression to maintain homeostasis. The EnvZ-OmpR system is an example of: A. a two component signal transduction system B. a one component signal transduction system C. a quorum sensing regulation system D. catabolite repression - Solution A. a two component signal transduction system E.coli deleted for the xylR gene (lack the gene entirely) will not express the xylAB operon (xylA, xylB) at high levels in growth medium rich in both glucose and xylose. Pick the hypothesis below you believe best explains the observation A. glucose binds the promoter of the xylAB operon inhibiting transcription of the xylAB operon B. Xylose is an inducer that induces transcription of the xylAB operon. In the presence of glucose, a cellular enzyme destroys xylose not allowing it to act as an inducer and induce transcription of the xylAB operon. C. Xylose is an inducer that induces transcription of the xylAB operon. In the presence of the glucose, very little xylose is imported into the cell due to inducer exclusion. This results in low transcription of the xylAB operon. D. Catabolism of glucose by glycolysis produces a byproduct that inhibits transcription of the xylAB operon. - Solution C. Xylose is an inducer that induces transcription of the xylAB operon. In the presence of the glucose,
very little xylose is imported into the cell due to inducer exclusion. This results in low transcription of the xylAB operon. In addition to the xylAB operon, XylR also regulates a different monocistronic operon called the xylE operon. Organization of these two operons under control of XylR is referred to as a: A. Regulon B. Intron C. Megatron D. Operon Network - Solution A. Regulon Dr. Strummer is working with Vibrio cholerae El Tigre, a bacteria that has a mutation in the ctxA gene. The mutation has changed the 5th codon in ctxA from the codon for phenylalanine to the codon for isoleucine. This mutation is an example of: A. silent mutation B. missense mutation C. nonsense mutation D. stop mutation - Solution B. missense mutation Using transformation and generalized recombination, Dr. Strummer changes the mutant 5th codon in the ctxA gene of Vibrio cholerae El Tigre from the codon for isoleucine back to the normal codon for phenylalanine. This mutation is an example of: A. second-site reversion B. dna repair C. retraction D. true reversion - Solution D. True reversion A mutation in the DNA code of the lacY gene is referred to as a change in A. genotype B. phenotype C. karyotype D. idiotype - Solution A. genotype Tetracycline is a: A. bacteriostatic antibiotic that inhibits translation elongation B. bactericidal antibiotic that inhibits translation elongation C. bactericidal antibiotic that inhibits transcription
A. lytic or virulent B. temperate C. lysogenic D. cytotoxic - Solution A. lytic or virulent T4 is an example of a __________________ bacteriophage, while Lambda is an example of a ______________ bacteriophage: A. temperate, virulent B. lysogenic, lytic C. virulent, temperate D. lytic, specialized - Solution C. virulent, temperate What would be the consequence of deleting the late T4 genes? A. the T4 genome would not be copied B. T4 mRNA would not be produced C. ATP would not be produced D. T4 capsid proteins would not be made - Solution D. T4 capsid proteins would not be made How do bacteriophage influence bacterial evolution? A. bacteriophage cause cleavage and rearrangement of bacterial genomes, thus accelerating bacterial evolution B. bacteriophage lyse mutated bacterial cells, thus preventing them from replicating and passing on their genetic information C. bacteriophage transfer genetic information between bacterial cells through transduction, thus increasing the genetic diversity of bacterial populations D. bacteriophage decrease the size of bacterial populations and thus decreasing genetic diversity and slowing down bacterial evolution - Solution C. bacteriophage transfer genetic information between bacterial cells through transduction, thus increasing the genetic diversity of bacterial populations Lambda phage infects a bacteria growing in poor growth media. Which of the following statements is TRUE. A. Lambda phage will enter the lysogenic cycle due to high levels of CII which directly positively regulates CI repressor B. Lambda phage will enter the lysogenic cycle due to high levels of CIII which directly positively regulates CI repressor
C. Lambda phage will enter the lytic cycle due to low levels of CII which directly negatively regulates CI repressor D. Lambda phage will enter the lytic cycle due to high levels of CIII which directly negatively regulates CI repressor - Solution A. Lambda phage will enter the lysogenic cycle due to high levels of CII which directly positively regulates CI repressor True or False: Viruses that have (-) sense single stranded RNA genome can utilize a host RNA polymerase to transcribe its genome into mRNA - Solution False True or False: Release of an animal virus from a host cell always requires lysis of the host cell - Solution False Which of the following viral activities is not observed during the latent period of the viral life cycle? A. synthesis of viral nucleic acid B. translation of viral proteins C. assembly of virions (complete viral particles) D. release of virions from the host cell - Solution D. release of virions from the host cell In one form of DNA transfer between bacteria, the DNA is transferred from one cell to another in a bacteriophage. This is referred to as: A. transition B. transformation C. conjugation D. transduction - Solution D. transduction The passing of genes from parent cells to daughter cells is called - Solution vertical gene transfer A Lambda prophage will become lytic under which of the following conditions: A. the infected bacterium finds itself in rich growth media and can undergo rapid growth B. the infected bacterium finds itself in poor growth media and can undergo limited growth C. the infected bacterium undergoes DNA damage
