Bio 2010 - Microbiology » Spring 2023 » Lecture Exam 3

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Question #1
Why is oxygen necessary in aerobic cellular respiration?
A.   it is needed for glycolysis, which begins the process of respiration in cells.
B.   it provides the hydrogen nuclei needed to create a proton gradient outside of the cell
C.   it is the final electron acceptor in the electron transport chain.
D.   it is important in creating oxaloacetic acid in the Krebs cycle.
Question #2
What phase of cellular respiration has the highest ATP yield?
A.   oxidative phosphorylation
B.   the transition reaction
C.   the Kreb's cycle
D.   fermentation
E.   glycolysis
Question #3
Dinitrophenol (DNP) is a drug that has the ability to separate the flow of electrons through the electron transport and ATP proton pumps, used during the electron transport system. This means that the energy from electron transfer cannot be used for ATP synthesis. Assuming your bacteria has consumed DNP, how many ATPs would they produce form the complete, aerobic oxidation of one glucose molecule?
A.   38
B.   2
C.   4
D.   0
Question #4
The proton motive force is:
A.   the movement of flagella
B.   a H+ electrochemical gradient formed across the plasma membrane
C.   the movement of water across a membrane
D.   ATP accumulation in the plasma membrane
E.   the accumulation of water formed in respiration
Question #5
In the final step of the electron transport system, the rotation of the proton pump provides the energy for ATPase to enzymatically make ATP. What specifically is responsible for rotating this pump?
A.   Proton motive force from incoming H+ ions
B.   Proton motive force from incoming ATP
C.   Proton motive force from incoming O2
D.   Proton motive force from income CO2
Question #6
Which of the following statements is an accurate description of what happens in electron transport?
A.   The final electron acceptor is oxidized.
B.   The electrons gain energy with each transfer in the chain.
C.   NADH and FADH are reduced.
D.   NADH and FADH are oxidized.
Question #7
What is the difference between a reversible and non-reversible, competitive inhibitor?
A.   both permanently attaches to the enzymes active site
B.   neither one attaches to any location on an enzyme
C.   both permanently attaches to the enzymes allosteric site
D.   reversible temporarily attaches to the enzymes active site
Question #8
Which of the following does NOT directly affect the activity of an enzyme?
A.   pH
B.   substrate concentration
C.   temperature
D.   oxygen concentration
Question #9
How does extreme temperature affect mesophilic proteins?
A.   destroys products
B.   preserves existing chemical bonds
C.   destroys substrates
D.   breaks chemical bonds
Question #10
Substrates and enzymes capable of interacting to form products in a chemical reaction, must first overcome a thermodynamic barrier known as the reaction's:
A.   activation energy.
B.   free-energy content.
C.   equilibrium point.
D.   entropy.
E.   endothermic level.
Question #11
An oxidation enzymatic reaction is a reaction that:
A.   loses an electron
B.   gains an electron
C.   decreases the temperature
D.   increases the pH
Question #12
Which of the following best describes enzyme saturation?
A.   enzymes active site is occupied ATP
B.   enzymes active site is not occupied by anything
C.   enzymes active site is occupied by substrate
D.   enzymes active site is occupied by O2
Question #13
Microbial fermentation can be detected in laboratory identification by observing a change in:
A.   pH
B.   oxygen levels
C.   temperature
D.   glucose levels
Question #14
Fermentation pathways make ATP and NADH. The ATP is used for a variety of cell functions. Why do fermenting cells need to make NADH?
A.   to use in the transition reaction
B.   to make more toxic final products
C.   to use in the Electron Transport System
D.   to use in the Kreb's cycle
E.   to make less toxic final products
Question #15
Which of the following statements regarding glycolysis is FALSE?
A.   oxidation of glucose is complete
B.   oxidation of glucose yields NADH
C.   oxidation of glucose yields pyruvic acid
D.   oxidation of glucose yields ATP
Question #16
ATP is an energy rich molecule because:
A.   the bonds between the phosphate groups are very stable.
B.   the bonds between the phosphate groups are unstable.
C.   the three phosphate groups are strongly attracted to each other.
D.   the sugar in ATP has numerous carbon-hydrogen bonds.
Question #17
Pyruvic acid cannot advance into the Krebs cycle. It must first be converted into a product that can be further oxidized in Krebs cycle. What is the name of this transformed molecule that starts Krebs cycle?
A.   CO2
B.   oxaloacetic acid
C.   acetyl CoA
D.   NAD+
E.   phosphoglyceric acid
Question #18
Which of the following is NOT a similarity that BOTH the Kreb's and the Calvin Benson cycle share, or have in common?
A.   both cycles have more than one chemical reaction
B.   both cycles oxidize compounds
C.   both cycles produce ATP
D.   both cycles can start and stop
E.   both cycles recycle their final products
Question #19
Pyruvic acid, the end product of glycolysis, enters the citric acid cycle after it has been converted to:
A.   oxaloacetic acid.
B.   citric acid.
C.   acetyl-CoA.
D.   none of these.
E.   NADH.
Question #20
The Kreb's cycle completes two full turns for the oxidation of all pyruvic acid from glycolysis. How many total NADH molecules are made from Krebs cycle reactions only?
A.   8
B.   0
C.   6
D.   2
E.   4
Question #21
Which of the following is a Photosystem II specific product?
A.   phosphogyceric acid
B.   CO2
C.   NADPH
D.   Glucose
E.   ATP
Question #22
Which of the following is released as a photosynthesis byproduct or waste product?
A.   water
B.   carbon dioxide
C.   oxygen
D.   carbon
Question #23
A photosynthetic bacteria is exposed to a toxin that destroys NADPH. The levels of RuBP and glucose should:
A.   both decrease
B.   RuBP increases and glucose decreases
C.   both increase
D.   glucose increases and RuBP decreases
Question #24
During the reduction phase of the Calvin-Benson cycle, phosphoglyceric acid is ultimately reduced in order to make:
A.   ribulose 1,5 รข bisphosphate (RuBP); NADP+ & H+
B.   phosphoglyceraldehyde; NADP & H+
C.   pyruvic acid; NADP+ & H+
D.   phosphoglyceraldehyde; ATP
Question #25
In eukaryotes, gene expression is primarily regulated at the level of:
A.   translation
B.   protein synthesis
C.   transcription
D.   replication
Question #26
Which of the following statements is TRUE regarding gene regulation in bacteria?
A.   activator proteins bind near promoters and increase efficiency of translation.
B.   enhancers are commonly used to regulate transcription.
C.   genes with related functions are often grouped together and have a single start codon.
D.   small-molecule sensors usually bind DNA and change its 3D structure allosterically.
E.   repressor proteins block transcription by binding to operator sequences.
Question #27
Transcription of the structural genes in an inducible operon:
A.   starts when the pathways product is present.
B.   occurs continuously in the cell.
C.   stops when the pathway's product is present.
D.   does not result in the production of enzymes.
E.   starts when the pathway's substrate is present.
Question #28
The lactose operon is likely to be transcribed when:
A.   the cyclic AMP and lactose levels are both high within the cell.
B.   there is more glucose in the cell than lactose.
C.   there is glucose but no lactose in the cell.
D.   the cAMP level is high and the lactose level is low.
E.   the cyclic AMP levels are low.
Question #29
The lac operon genes only become expressed if:
A.   lactose binds to the repressor
B.   glucose binds to the repressor
C.   lactose binds to the operator
D.   the repressor binds to the operator
Question #30
Genes transferred from one cell to another is called:
A.   vertical gene transfer
B.   transfer of gene
C.   horizontal gene transfer
D.   gene transfer
Question #31
Bacterial conjugation is an example of:
A.   vertical gene transfer
B.   horizontal gene transfer
C.   transduction
D.   bacterial transformation
Question #32
In Griffith's experiments, the transforming substance was:
A.   proteins
B.   RNA
C.   enzymes
D.   DNA
Question #33
The transfer of genetic material between two bacteria in direct physical contact through the use of a pilus is called:
A.   transformation
B.   transduction
C.   vertical gene transfer
D.   conjugation
Question #34
Which of the following mutations results in a non-functional protein because a stop codon appeared too early in the mRNA sequence?
A.   missense
B.   frameshift
C.   silent
D.   nonsense
Question #35
Original DNA sequence: ATC CAT Mutated DNA sequence: ATC GCAT. What type of mutation occurred?
A.   insertion
B.   deletion
C.   silent
D.   point mutation
Question #36
A nonsenese mutation is a point mutation, usually in the second nucleotide position, and does which of the following?
A.   changes one single amino acid
B.   introduces a stop codon
C.   deletes the entire protein
D.   eliminates the start codon
E.   creates a new protein
Question #37
A type of substitution in which no amino acids change is called:
A.   Deletion
B.   missense
C.   silent
D.   nonsense
Question #38
Where does the energy come from to replicate complimentary copy DNA strands?
A.   electrical charge attraction
B.   dNTP' s
C.   osmosis
D.   kinetic charge attraction
E.   diffusion
Question #39
DNA molecules are made up of subunits called nucleotides. How many different types of nucleotides are used to make DNA molecules?
A.   four types
B.   one type
C.   three types
D.   two types
Question #40
All of the following are true statements concerning DNA structure, EXCEPT:
A.   DNA contains the nitrogenous bases A, C, G, and U.
B.   the two strands of a DNA molecule are held together by hydrogen bonds.
C.   DNA contains the sugar deoxyribose.
D.   the two strands of a DNA molecule are antiparallel to each other.
Question #41
Which enzyme unzips or separates the DNA helix in order to expose the two parental DNA strands and creates a replication fork?
A.   DNA ligase
B.   DNA polymerase
C.   DNA helicase
D.   DNA gyrase
Question #42
There are 64 codons and 20 amino acids. Which of the following is true?
A.   Some amino acids have no link to a codon.
B.   Each codon specifies a different amino acid.
C.   Several different codons can specify the same amino acid.
D.   Each amino acid is specified by only one codon.
Question #43
Which of the following is the best description of a gene?
A.   a sequence of DNA nucleotides that codes for a single protein
B.   a single nucleotide
C.   a sequence of amino acids in a protein
D.   the entire DNA molecule
Question #44
In our lecture, I compared condons to:
A.   people on the bus
B.   words of a language
C.   MnMs in a bag of candy
D.   stars in the universe
Question #45
If ATCG is the triplet DNA code, then the ANTICODON would be:
A.   UTGC
B.   AUGC
C.   TAGC
D.   UAGC
Question #46
During translation, tRNAs anticodons recognize and attach to mRNA codons. What specifically do tRNAs bring to translation?
A.   a protein
B.   an amino acid
C.   a lipid
D.   a sugar

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