MIC 205A Dr. Jan Decker, Dr. Stephen Billington
Exam 2 KEY
October 12, 2007
Part 1 MULTIPLE CHOICE: Read each question and the answers carefully. Pick the one BEST answer and darken the corresponding letter on the scantron. Each answer is worth 3 points, for a Part one total of 90 points.
- Which of the following is NOT true about glycolysis?
- a.Energy is generated in the form of ATP.
- b.CO2 is released as a result of several decarboxylation reactions.
- c.One molecule of glucose is converted to two molecules of pyruvic acid.
- d.The reduced coenzyme NADH is produced.
- A ligase (WHITE) isomerase (YELLOW) transferase (GREEN) enzyme catalyzes
- a.joining two molecules together.
- b.rearrangement of atoms in a molecule.
- c.redox reactions.
- d.transfer of functional groups.
- (WHITE) A mutation where one or more bases are inserted or deleted from the DNA sequence is called a _____________ mutation.
- a.frameshift
- b.missense
- c.nonsense
- d.silent
- (YELLOW) A mutation where a base substitution inthe DNA sequence results in no amino acid change in the protein is called a _____________ mutation.
- a.frameshift
- b.missense
- c.nonsense
- d.silent
- (GREEN) A mutation where a base substitution in the DNA sequence results in a stop codon in the mRNA is called a _____________ mutation.
- a.frameshift
- b.missense
- c.nonsense
- d.silent
- (WHITE,YELLOW) A non-competitive enzyme inhibitor binds to
- a.a site on the enzyme other than the active site.
- b.the active site of the enzyme.
- c.the end product of the reaction.
- d.the substrate of the reaction.
- (GREEN) A feedback enzyme inhibitor binds to
- a.a site on the enzyme other than the active site.
- b.the active site of the enzyme.
- c.the end product of the reaction.
- d.the substrate of the reaction.
- In the third step of the TCA cycle, isocitrate and NAD+ are converted to alpha-ketoglutarate, CO2, NADH and H+. This is an example of a(n)
- a.isomerization reaction.
- b.polymerization reaction.
- c.redox reaction.
- d.substrate-level phosphorylation reaction.
- In the electron transport chain,
- a.ATP is generated by substrate-level phosphorylation.
- b.energy from ATP is consumed.
- c.energy is released through a series of redox reactions.
- d.protons are transported into the cell across the plasma membrane.
- Spontaneous mutations
- a.always result in an amino acid substitution in the corresponding protein.
- b.are caused by errors in DNA replication.
- c.are caused by UV radiation.
- d.result from the interaction of DNA with mutagenic agents.
- Enzymes increase the rate of chemical reactions by
- a.altering the pH of the environment.
- b.binding irreversibly to the substrate.
- c.decreasing the activation energy of the reaction.
- d.increasing the activation energy of the reaction.
- In an operon,
- a.a single gene is transcribed into multiple mRNA transcripts.
- b.a single protein is translated from multiple mRNA transcripts.
- c.multiple genes are transcribed on a single mRNA transcript.
- d.RNA is transcribed into DNA.
- What is the basis of the Ames test?
- a.Carcinogens will cause cancer in animals.
- b.Mutagens will revert a histidine-requiring mutant.
- c.Mutagens cause spontaneous mutations.
- d.Salmonella can grow in the presence of rat liver extract.
- (WHITE)The process of transformation requires
- a.a bacteriophage.
- b.close contact between donor and recipient cells.
- c.plasmid DNA.
- d.the uptake of naked DNA.
- (GREEN)The process of transduction requires
- a.a bacteriophage.
- b.close contact between donor and recipient cells.
- c.plasmid DNA.
- d.the uptake of naked DNA.
- (YELLOW)The process of conjugation requires
- a.a bacteriophage.
- b.close contact between donor and recipient cells.
- c.chromosomal DNA.
- d.the uptake of naked DNA.
- The generation of ATP by the transfer of electrons from nutrients down an electron transport chain, followed by chemiosmosis is called
- a.oxidative phosphorylation.
b.photophosphorylation.
- c.substrate-level phosphorylation.
- d.the TCA cycle.
- In repressible operons, a corepressor
- a.binds to RNA polymerase and allows it to transcribe the operon.
- b.binds to the operator site preventing transcription.
- c.binds to the repressor protein preventing it from binding to the operator site.
- d.binds to the repressor protein allowing it to bind to the operator site.
- The most powerful form of radiation for killing microbes is
- a.ionizing radiation.
- b.microwaves.
- c.uv radiation.
- d.visible light.
- During transcription, a promoter sequence is the site at which
- a.DNA polymerase binds on the DNA.
- b.RNA polymerase binds on the DNA.
- c.the ribosome binds on the mRNA.
- d.transcription is terminated.
- (YELLOW, GREEN) Bacteria in lag phase growth
- a.are adapting to new growth conditions by de-repressing operons.
- b.are most sensitive to physical and chemical control methods.
- c.double in size every 20 minutes.
- d.All of the above are true.
- (WHITE) Bacteria in log phase growth
- a.are least sensitive to physical and chemical control methods.
- b.double in size every 20 minutes.
- c.will give the most similar numbers for colony counts and microscopic counts.
- d.All of the above are true.
- Horizontal gene transfer involves
- a.a one way transfer of DNA from a donor to a recipient cell.
- b.a two way transfer of DNA between donor and recipient cells.
- c.transcription of DNA into RNA.
- d.transfer of genes from an organism to its offspring.
- During DNA replication, the enzyme DNA polymerase I
- a.joins DNA fragments together on the lagging strand.
- b.replaces RNA segments on the lagging strand with DNA.
- c.synthesizes short RNA segments on the lagging strand.
- d.synthesizes the leading strand.
- Listeria monocytogenes
- a.can live inside monocytes.
- b.is a thermophile.
- c.is usually transmitted in improperly canned vegetables.
- d.produces endospores.
- Which of the following generates the most energy in the form of ATP?
- a.Aerobic respiration
- b.Anaerobic respiration
- c.Fermentation
- d.The phoshogluconate pathway
- Which of the following types of gene transfer requires an F-pilus?
- a.Conjugation
- b.Generalized Transduction
- c.Specialized Transduction
- d.Transformation
- During (WHITE) aerobic respiration, the terminal electron acceptor is
- a.an inorganic molecule other than oxygen.
- b.an organic molecule.
- c.glucose.
- d.oxygen.
- During anaerobic respiration (YELLOW), the terminal electron acceptor is
- a.an inorganic molecule other than oxygen.
- b.an organic molecule.
- c.glucose.
- d.oxygen.
- During fermentation (GREEN) respiration, the terminal electron acceptor is
- a.an inorganic molecule other than oxygen.
- b.an organic molecule.
- c.glucose.
- d.oxygen.
1 2 3 4
- The organism growing in tube #1 (WHITE) #3 (YELLOW) #4 (GREEN) above is a(n)
- a.facultative anaerobe.
- b.microaerophile.
- c.obligate aerobe.
- d.obligate anaerobe.
- An autotroph
- a.automatically moves towards higher O2 concentrations.
- b.gets its carbon from CO2.
- c.gets its energy from light.
- d.is killed by high concentrations of O2.
- In 1997, San Diego CA was detecting high numbers of E. coli in a children’s pool area; harbor seals were sunning themselves on a nearby cove. The bands in the DNA fingerprint shown above demonstrating matching between the E. coli in the pool (A) and the E. coli from sea lions (3) are
- a.chromosomes.
- b.DNA pieces cut by restriction endonucleases.
- c.DNA pieces copied using PCR.
- d.genes.
- During translation, the codon in the mRNA is recognized by the ________ of the tRNA. The tRNA has the appropriate _________ attached to be incorporated into the protein being synthesized.
- a.anticodon, amino acid
- b.anticodon, nucleotide
- c.peptide, sugar
- d.RNA polymerase, ribosome
- Bt cotton that carries a gene for Bacillus thuringiensis toxin that kills pests that eat the growing cotton is a
- a.genetically modified organism.
- b.recombinant organism.
- c.transgenic organism.
- d.All of the above describe Bt cotton.
- The primers used in PCR control which DNA is copied because they
- a.block copying of all but the desired DNA.
- b.cause mutations in the unwanted DNA sequences.
- c.form double-stranded DNA needed by DNA polymerase to begin replication.
- d.have the correct 5’--->3’ orientation for DNA replication.
- In the lac operon, which of the following would happen if the LacI repressor protein was mutated so that it could no longer bind lactose, but could still recognize the operator site?
- a.The lac operon would be constitutively transcribed regardless of whether lactose was present or not.
- b.The lac operon would be transcribed only in the absence of lactose.
- c.The lac operon would not be transcribed regardless of whether lactose was present or not.
- d.The lac operon would only be transcribed in the presence of lactose.
- Clostridium botulinum
- a.endopores are killed by commercial sterilization.
- b.must live inside humans or animals.
- c.Is a microaerophile.
- d.All of the above are true.
Part 2 ESSAY: Answer 2 of the questions below in the space provided. Each correct answer is worth five points, for a Part 2 total of 10 points.
31. List 5 factors that influence the effectiveness of a chemical disinfectant.
- Numbers of microbes
Characteristics of microbe (spore, enveloped virus, etc)
Whether organism is metabolically active/log phase growth
Nature of chemical agent (how it works)
Time of contact
Temperature
pH
Presence of organic materials
32. Describe how ATP is generated from the electron transport chain during respiration.
-NADH and FADH from glycolysis and TCA give electrons to ETC
-electrons pass down the chain by redox reactions with the release of small pockets of energy
-Energy for redox reactions in ETC is used to pump protons across the membrane and set up a proton concentration gradient (proton motive force)
-protons diffuse back across the membrane through ATP synthase
-ATP synthase couples the energy released from the protons diffusing back across the membrane to the synthesis of ATP from ADP (chemiosmosis)
Things that might earn points if they don’t get all the points above
-transfer of electrons directly from NADH to O2, would release too much energy for cell to use efficiently
-NADH gives 3 ATP, FADH gives 2 ATP
-Generation of ATP from the electron transport system is called oxidative phosphorylation
33. Describe the process of transcription.
-RNA polymerase binds to the promoter (RNA polymerase binding site) of a gene and the DNA unwinds
-RNA polymerase begins synthesis of an RNA copy of the DNA coding strand
-uses the DNA template strand as a template and brings in complementary RNA nucleotides
-RNA is synthesized in the 5’-3’ direction
-RNA synthesis stops when RNA polymerase comes to a terminator sequence in the DNA
Things that might earn them points if they don’t get all the points above
- The U in RNA base pairs with the A in DNA
- DNA rewinds as newly synthesized RNA leaves the DNA
Turn in only this page with your scantron; make sure your name is on it!
