Microbio Final exam (old material)
Protons have different sources and different fates in bacterial ETS. Which of the following processes does NOT generate protons?
The production of water from the use of oxygen as a terminal electron acceptor
The first steps in bacterial DNA replication are represented in the figure below, in which the letters T and U point to ________, respectively.
strand separation at the 13-mer repeats and binding of DnaA proteins at the 9-mer repeats
Which of the following substrates is an electron donor in organotrophy?
succinate
The importance of the stop codon UAG is that it
tells the ribosome to stop translating the mRNA
A feature common to all cellular control mechanisms is
the ability to sense that something inside or around the cell has changed
SRP stands for ________, and it plays a role in ________.
signal recognition particle; movement of protein to membrane
SARS-CoV-2 virus is a:
ssRNA virus
The significance of the Shine-Dalgarno sequence is that it is the site where:
a ribosome binds to mRNA so that it can initiate translation
tRNA molecules carry what main two components to the ribosome?
an anticodon and corresponding amino acid
What is the connection between catabolic pathways like respiration and biosynthesis?
The production of reducing power, energy, and building blocks from catabolism for biosynthesis
Which regulatory RNA occurs in the intergenic region?
sRNA
In U.S., it is the responsibility of FDA Center for Biologics Evaluation and Research (CBER) to regulate vaccines. Vaccine development consists of:
3 phases, first testing safety, then safety and efficacy. Each phase takes months to years.
The sigma-70 factor of E. coli (RpoD) recognizes promoters for
"housekeeping" genes
The Baltimore classification of viruses is based on the:
- Genome composition - Origin of envelope - Mechanism of replication - Mechanism of mRNA expression
Ms Karwah:
- was an Ebola survivor - was a Time magazine person of the year in 2014 for her work in support of other Ebola victims - died in 2017 of blood loss during childbirth because no one would help her due to the stigma of her having had Ebola
What size should the pores of a water purifying filter be to make sure it traps all the microorganisms including viruses?
20 nanometer
The figure shown below diagrams three pathways for the metabolism of glucose. Pathway ________ is most likely to be used for biosynthesis because it can be used to ________.
3; make carbon backbones of many lengths
Many restriction enzymes recognize palindromic sequences on double-stranded DNA. Among the following, which is a palindromic sequence?
5'-GGATCC-3' 3'-CCTAGG-5'
Examine the DNA sequence shown below. How many possible reading frames does this piece of DNA have? 5'-AGTCGATCGAACGGTCATCG-3' 3'-TCAGCTAGCTTGCCAGTAGC-5'
6
Which reaction would have the most negative dG?
ATP -> ADP
Which of the following statements is NOT true?
All viruses have a phospholipid envelope
The two main functional regions of a tRNA molecule are:
Anticodon region and 3' acceptor end
The first person to see bacteria under the microscope:
Antoni van Leeuwenhoek
Which of the following are synthesized via a branched pathway involving chorismate?
Aromatic amino acids
Which energy carrier(s) also carry electrons by reducing one or more aromatic rings?
Both FAD+ and NAD+
Lysogeny refers to the viral state in which:
Both that the viral genome may be integrated into the host genome and there is active reproduction of the virus which is modulated such that virions are produced and released, but the cell lives
The sliding clamp is used in DNA replication to ________ and is loaded by ________.
Bring and tether DNA polymerase to the chromosome; a clamp-loader complex
A methanogenic archaea living within a landfill produces methane gas that can be used for energy. Which pathway below is correct for energy production by this bacterium?
CO2 + H2 -> ETS -> CH4 + ATP
A methanogenic archaea living within a landfill produces methane gas that can be used for energy. Which pathway below is correct for carbon assimilation (biosynthesis pathway) by this bacterium?
CO2 -> Calvin cycle -> G3P -> glucose
______________ is the breakdown of complex molecules into smaller ones, while ____________ include reactions that build cell material.
Catabolism, anabolism
A soil bacterium oxidizes sugars and other organic compounds in the soil for energy and to build cell material. This type of microbe is a:
Chemoorganotroph
Some bacteria in the human gut microbiota primarily feed on glucose derivatives from mucus secretions, in essence they "farm" the mucus. The mucus contains many sugar-acids which tend to be catabolized by which pathway?
Entner-Doudoroff pathway
In the figure below, which depicts the activation step in bacterial DNA replication, the letter Q points to ________, and the letters R and S point to ________, respectively.
DnaA protein; 9-mer repeats within oriC and 13-mer repeats
While testing the chemiosmotic theory, researchers prepared "inside-out" vesicles. In an inside-out vesicle, the F1 subunit of the proton-ATPase faces outward. Using the figure below, which statement is true about the key results of these experiments.
Either a high concentration of protons inside the cell or a highly positive charge inside the cell can drive ATP synthesis by moving protons down a concentration or charge gradient
DNA from a bacterium could not be added to the DNA of a eukaryote because they are different types of DNA molecules.
False
The first microscope ever built (by Robert Hooke) had a magnification power of 30X. This was high enough to be able to see most bacteria.
False
Which of the following is NOT true of initiation of transcription?
GTP hydrolysis catalyzes bubble formation in DNA so that DNA polymerase can replicate a DNA strand
Glucose -> glycolysis -> pyruvate -> acetyl-CoA -> TCA cycle -> ETS + O2-> ATP + water
Glucose -> glycolysis -> pyruvate -> acetyl-CoA -> TCA cycle -> ETS + NO3 -> ATP + NO2
What is the correct pathway with major processes and intermediates given below for energy production by E. coli during aerobic respiration?
Glucose -> glycolysis -> pyruvate -> acetyl-CoA -> TCA cycle -> ETS + O2-> ATP + water
Which two amino acids are important for nitrogen sensing and regulation in most bacteria?
Glutamate and glutamine
You have successfully started culturing a new bacterial isolate from your hydrothermal vent expedition to collect previously undiscovered bacteria with potentially novel metabolism. Key to this success was the addition of an unusual amino acid 3-nitrotyrosine. This amino acid is therefore considered to be what?
Growth factor
What types of bacteria would NOT perform the Calvin cycle, to fix CO2?
Heterotrophs
During conjugation when a 'fertility plasmid' becomes integrated into the genome of the new cell, this new cell with the integrated F genes is referred to as what?
Hfr
transmissible spongiform encephalopathy (TSE) refers to what kind of disease?
Holes are formed in brain tissue, may involve malformed proteins but the disease agent is not fully known
A microbe has the capacity to do both fermentation and respiration. Under what conditions will the products of glycolysis be used for fermentation rather than respiration?
In the absence of oxygen or other strong terminal electron acceptor
In anaplerotic reactions,
Intermediates in a pathway are regenerated
How does the AraC regulatory protein turn on transcription in the presence of arabinose?
It becomes more flexible, so that the dimer can bind to the araI components of DNA and interact with RNA polymerase to permit transcription
What is NOT true about the polio virus?
It is transmitted by coughing
Using the genetic sequence below the table, first find the start codon then translate the peptide starting at the start codon. Which of the following peptides might the message below the table code for? 5'-GAGUUAUGCACGGGUUCUAUGUGUAG-3'
MET-HIS-GLY-PHE-TYR-VAL
What does it mean to say that the genetic code is redundant?
More than one codon can specify the same amino acid
In many bacteria, the electron carrier ________ is used for biosynthesis, whereas ________ feeds the electron transport system
NADPH; NADH
You are a scientist at the university agricultural extension, and you get a call from Mr. Rawley from our story in the "Farmer's Dilemma." Mr. Rawley has questions and concerns about the construction of genetically modified organisms and says: ....... Is Mr. Rawley correct that bacterial DNA cannot become a permanent part of a corn cell? Why or why not?
No, he is not correct because DNA sequences are universal, therefore bacterial DNA can be integrated into the corn DNA and "read" by corn cell DNA and RNA proteins
Which of the following pathways is NOT a route for CO2 assimilation?
Pentose phosphate pathway
The inversion shown below of the H segment promoter is what kind of gene regulation? And can help a pathogen do what?
Phase variation, evade host cells
Which of the following is NOT part of initiation of transcription?
RNA polymerase pauses and the Rho protein binds to the mRNA
In gene regulation, ________ prevent transcription, whereas ________ stimulate transcription.
Repressors; activators
A sulfate reducing bacterium (an autotroph) living in seawater on the iron surface of bridge support may be detrimental to the integrity of that bridge material. Which pathway below is correct for energy production by this bacterium and shows the product that can facilitate corrosion of the iron support? (sulfate = SO42-)
SO42- -> ETS -> H2S + ATP
How does the reductive (reverse) TCA cycle participate in carbon fixation?
Some of the TCA reactions occur in reverse, assimilating small amounts of CO2
You are a have successfully started culturing a new bacterial isolate from your hydrothermal vent expedition to collect previously undiscovered bacteria with potentially novel metabolism. Upon transfer to new medium the population of the bacteria grow quickly and then slow down, remaining at about the same cell density over time. The time during which growth has slowed is called:
Stationary phase
G-C rich regions of DNA require more energy to melt. This is because:
The bases guanine and cytosine share three hydrogen bonds rather than the two hydrogen bonds between adenine and thymine
Which of the following steps is not part of the life cycle of a lytic phage?
The phage DNA integrates into the bacterial chromosome.
The figure below shows a regulatory being produced on the left. Based on the information available in the figure, this protein likely functions in which of the following ways?
The regulatory protein binds to the operator and induces transcription
Reduction potential is defined as
The tendency of a compound to accept electrons.
What is TRUE about marine viruses?
They are highly abundant and diverse, but not well characterized
The only transport pathway that can move pre-folded proteins is called:
Twin arginase translocase
Which protein complex can move pre-folded proteins out of the cytoplasm?
Twin arginase translocase
You are a researcher interested in characterizing the structure of a protein found to confer bacterial resistance to a new antibiotic. Which of these visualization tools would be of most use to you?
X-ray crystallography
You are a microbiologist working on an infectious disease called Miceattack, which kills laboratory mice within 2-3 days. You suspect that the culprit is a bacterium called Bacillus killmicus; however, your colleagues are skeptical. You have already shown that the blood from the diseased mice have rod-shaped bacteria associated with it whereas blood from healthy mice do not. Following Koch's postulates, you have also isolated the bacterium in pure culture and shown that it is the same rod-shaped bacterium you see in the sick animals. What would you do next to convince your colleagues? (You must follow Koch's postulates)
You would reinject the isolated bacteria into healthy mice. If the previously healthy mice get sick, you would reisolate the bacterium in pure culture. If this is identical to the original bacterium, this is definitive proof that Bacillus killmicus causes Miceattack.
Which form of gene regulation/control is the LEAST reversible and MOST drastic?
alternation of DNA sequences
A crucial part of the process to create GMO corn is the construction of the right plasmid. The plasmid used in this process is originally from Agrobacterium which can naturally infect plant cells. The plasmid is grown in E. coli so that we can make many copies of the plasmid quickly and then the plasmid is isolated and grown in Agrobacterium which can then infect corn cells and integrate DNA from the plasmid into the corn genome. Knowing this information, what components should the plasmid include?
an ori for E. coli, ori for Agrobacterium, a selectable marker such as antibiotic resistance, the gene of interest along with a eukaryotic promoter
When two different strains of influenza virus infect a host simultaneously, their genomic segments can reassort to generate a novel hybrid phenotype. This phenotypic change is referred to as:
antigenic shift
Signal sequences for protein targeting are found where?
at the N-terminal end of a protein
Which of the following terms refers to an interdisciplinary field that uses computer programs to compare genes of different species?
bioinformatics
The image below shows what two processes for the lac operon?
cAMP and CRP bind DNA and increase rate of transcription; allolactose binds the repressor protein allowing lac gene operon transcription
HIV infection is:
can be controlled by HAART
When double-stranded DNA replicates, the newly made strand is related to its template strand because the two strands have
complementary sequences and are antiparallel to each other.
Which of the following is a process that involves cell-to-cell contact to move a plasmid from a donor cell to a recipient cell?
conjugation
During replication, the lagging strand is synthesized ________, while the leading strand can be synthesized ________.
discontinuously; continuously
The Influenza A virus genome has:
eight RNA segments that code for 10 proteins.
A branch of medical science concerned with the causes and origins of diseases is called:
etiology
The figure below shows a diagram of a DNA and a process. This microorganism is a(n) ________, and the process being diagrammed is ________.
eukaryote, splicing
Infection of cells occurs through interaction of viral Spike (S) protein with any cellular protein it comes in contact with
false
The ability of cohesive ends of DNA from different organisms to ________ constitutes the basis of recombinant DNA technology.
form complementary base pairs
The entire genetic complement of DNA in a cell of a particular organism is called
genome
Thinking about how a E. coli uses glucose and lactose, when both glucose and lactose are added to the growth medium, E. coli will likely have a growth curve that:
grows, levels off, and then grows again
In their work with soil bacteria, researchers found microorganisms that display metabolic pathways with net deltaG values as small (close to zero) as -20 kJ/mol. This is an example of
growth near the thermodynamic equilibrium
Which infectious agent is identified by the nucleic acid genome being the entire infectious particle?
viroids
The core RNA polymerase plus sigma factor together are called ________.
holoenzyme
The movement of genetic material from one cell into another cell (not daughter cell) is called
horizontal transmission
tRNA have a longer or shorter half-life compared to mRNA?
longer
A bacterium capable of producing methane and water from carbon dioxide and hydrogen performs a type of metabolism called ________ and, given its sources of electrons, it is a ________.
methanogenesis; chemolithotroph
In the figure below, which models DNA semiconservative replication, the numeral I points to ________, II points to ________, and III points to _______.
new daughter strands; origin; replication fork
Viruses are:
noncellular particles that take over the metabolism of a cell to generate more virus particles.
The term ________ describes a polycistronic messenger RNA whose expression is under control of a promoter.
operon
Beta-lactamases are proteins found in many bacteria that can degrade beta-lactam antibiotics such as ampicillin. Families of these proteins are coded by genes with similar sequences even though they are found in a variety of bacteria. These genes would be considered to be
orthologs
Which of the following is NOT a terminal electron acceptor in anaerobic respirations?
oxygen
Genes that have arisen from a duplication within a species and have evolved to carry out different functions are referred to as
paralogs
Besides the nucleoid, two other kinds of DNA molecules that may be present in the cytoplasm of a bacterial cell are ________ and the genomes of ________ (remember horizontal gene transfer).
plasmids; bacteriophages
In the pentose phosphate shunt, glucose 6-phosphate is oxidized to 6-phosphogluconate, which is then decarboxylated to ribulose 5-phosphate. What is the main metabolic role of this pathway?
production of carbohydrates with three to seven carbon atoms, which can be utilized in biosynthesis
Which of the following is NOT an end product of fermentation?
pyruvate
Increased levels of chaperones are known to increase heat resistance of bacteria because they
refold proteins damaged by heat so they function again
Increased levels of chaperones tend to increase the heat resistance of bacteria by
refolding proteins damaged by heat so they function again
Which of the following are required for the termination of translation?
release factors
The natural function of ________ is to cut the DNA of invading plasmids and phages at specific sequences.
restriction enzymes
Enzymes that modify the supercoiling of a DNA molecule are called
topoisomerases
After ________, each polypeptide must be properly folded and placed at the correct cellular or extracellular location.
translation
The term "________" is used to describe movement of a protein from one compartment to another.
translocation
Approximately 50% of people chronically infected with Hepatitis C virus (HCV) live in ten states, with five of those in Appalachia, and the highest rate of new infections is occurring in the 20-29 year-old population.
true
Dr. Li Wenliang reported respiratory disease cluster that looked like SARS in December 2019. He was chastised by the Chinese government and died of COVID-19 in February 2020.
true
Since the beginning of the AIDS epidemic about 35 million people have died
true
Chemoorganotrophy is a term describing microorganisms that
use preformed organic compounds as a source of electrons and obtain energy through fermentations or organic respiration.