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Microbio previous exam questions
Terms in this set (120)
Which of the following does NOT describe a prokaryote?
may have a membrane bound nucleus
rDNA-based phylogenetic trees are useful because rDNA is
more conserved than most genes so that representatives from each species can be compared
which argument does NOT support the RNA world hypothesis?
RNA is less stable than DNA
The earth is about ____ years old and microbes have lived on earth about ____ years.
4.5 billion, 3.5 billion
a new virus was found that contains an RNA genome, a capsid with helical symmetry, an RNA-dependent RNA replicase, and an RNA-dependent DNA polymerase. This virus is likely a
Whats shown in the picture below?
A crowd of temperate phage surround a dwindling number of host cels. to survive, this phage likely
becomes a prophage.
you isolated a new bacterium. it appears to be a gram positive rod shaped cell. you predict that the cell does not produce
sulfolobus has an idea growth at 80 degrees C, ideal water activity at .98, and pH optimum of 3. it is an
Which organisms are least likely to contain superoxide dismutase?
Marcy suspects there are proteobacteria growing in the chicken soup broth that has been sitting in her refrigerator. She boils the soup for 5 seconds. What is the most likely outcome of this heat treatment
The heat causes the microbial membranes to begin to melt and become more fluid
Which of the following is NOT a strategy used by hyperthermophiles
Unsaturated fatty acids in membrane lipids
Herpes simplex viruses are class I dsDNA viruses that cause latent infection in humans. Which of the following is true about the life cycle of Herpes simplex viruses
They replicate in the cytoplasm
Which of the following is NOT true about the Actinobacterium Streptomyces
It forms endospores
related to mitochondria and contain many human pathogens, including Salmonella?
Metabolic inhibitors that block energy production would inhibit
Which of the following is found in both gram-positive and gram-negative cell walls
Which of the following is not a function of the plasma membrane?
Anchor for the lipopolysaccharides (LPS)
Archaeal cell envelopes differ from bacterial cell envelopes in all of the following ways except
archaeal cell walls use D-amino acids
the picture below shows a
gram - negative cell envelope
Which species is most related to M. tuberculosis
R ruber KstD3 and R. erythropolis SQ1 are
equally related to M. tuberculosis
what kind of phylogenetic tree is this?
rooted phylogenetic tree
Which ancestor came first chronologically?
can't be determined
Louis Pasteur is NOT credited with
Inventing the microscope
who tracked the source of a cholera outbreak in London in 1854 to a public water pump, and thus contributed to the emerging "germ theory" of disease
which is NOT an advantage for smaller cells?
Better able to prevent predation by other
which is NOT true about bacterial flagella?
They use ATP to fuel flagellar rotation
Which of the following is NOT a feature of freeliving bacteria to survive harsh or changing environmental conditions?
which is false about endospores
They are a mechanism for reproduction and
dispersal of daughter cells
which is NOT true about protists
They form a single phylogenetic lineage
which term doesnt bleong
is smallpox considered a current bioterrorism threat?
Yes because some dormant virions in the environment may remain pathogenic for years
and because the genome of smallpox has been
published and is publically avilable
the picture below shows
an enveloped virus
which of the following is NOT a strength for microbial resistance to biocides
secrete a neutralizing metabolite
Decimal reduction (D) is NOT affected by
the initial number of cells
all phage life cycles include
Which of the following is the BEST way to eliminate endospore-forming organisms
Why don't Beta-lactam antibiotics work against Archaea
Archaea do not make peptidoglycan
A new antibiotic was just discovered. the MIC assay (shown below) was tested on a Bacteroidetes species. When tube A is diluted, growth occurs. What can be concluded about this antibiotic
it is bacteriostatic
The best way to describe the medium shown in the recipe below is "________ medium".
2. Which method could you use to both culture and enumerate the viable cell number of a mixed bacterial population from the soil?
e. Plating dilutions of the soil onto complex agar
3. Which of the following is NOT true about chemolithotrophy
a. An inorganic electron acceptor is used
4. Which of the following is NOT a requirement for oxidative phosphorylation
e. Electron carriers of decreasing reduction potential
5. The turbidity of E. coli strain K12 was compared to E. cowli over time and the data are shown in growth curve below. Which of the following conclusions can be made from the data?
b. E. cowli has a much longer lag phase
6. The growth rates shown for E. coli K12 in the growth curve above are likely __________ than the growth of E. coli in the human GI tract, because ______________.
a. Higher; growth conditions in lab are usually more favorable than conditions in nature
7. Which of the following redox pairs has the oxidized species written second
e. So / SO3-
8. Which of the follow is an example of a coenzyme that shuttles electrons between proteins
9. The reduction potential measures
c. The tendency of a molecule to accept electrons
10. Substrate-level phosphorylation (SLP) differs from oxidative phosphorylation (OP) because
e. SLP happens in the cell cytoplasm while OP occurs only at the membrane
11. Which of the following half reactions provides the best electron donor? (ΔE given in mV
. CO2 ⇒ CH2O - 430 mV
12. Given the following half reactions, which would be a favorable (exergonic) reaction
a. FMNH2 will donate electrons to Nitrate
13. ATP, Phosphoenolpyruvate, & 1,3-bisphosphoglycerate
d. All contain anhydride bonds
14. Chose the answer that has the correct order:
(PMF= proton motive force, ETC= electron transport chain, TCA= Tricarboxyllic acid cycle or Krebs
Glycolysis ⇒ TCA ⇒ ETC
15. Which statement is true about anaerobic respiration
e. It often uses the same components as aerobic respiration to generate a proton motive force
16. Which of the following is true about an iron-reducing bacterium in an aerobic environment
d. They use nanowires to give electrons to iron
17. Why would a bacterium run the electron transport chain in reverse
a. During photoautotrophy to generate reducing power
18. A microbe that lives in the dark and uses glucose as an electron source and inorganic sulfur as the terminal electron acceptor is a ______.
19. A purple non-sulfur bacterium
c. Can grow as a phototroph or a heterotroph
20. What is a negative consequence of denitrification
b. It results in the production of Nitrogen-based gasses that react with the ozone layer and contribute to global warming
21. Which of the following is true about the pathway with the PAPS intermediate (shown below) in an organism
d. It likely occurs with a lot less frequency than the APS-only branch of the pathway
22. During photosynthesis the light harvesting molecules
c. Transfer photons to the reaction center
23. Which of the following groups of organisms could be used to convert natural gas into organic products that are useful for human consumption
24. Which of the following is NOT a difference between oxygenic and anoxygenic phototrophs
b. Oxygenic phototrophs have cyclic electron transport chains while anoxygenic phototrophs have linear chains
25. Which of the following is NOT required for a rhodopsin-based phototroph
c. Electron transport chain
26. Green bacteria use specialized structures called __________ to capture photons in low-light environments
27. Which of the following is NOT true about syntrophy
a. It always involves the interspecies transfer of sulfate
28. Which of the following does NOT ultimately contribute to global warming
29. Which of the following is NOT true about Dead zones
d. Are zones where all life forms die off
30. Which of the following does NOT imply an intimate connection between two or more species
31. Which of the following is NOT true about Denitrification
e. It produces soluble nitrate
32. Which process is NOT used for dissimilation
b. Nitrogen fixation
33. Microorganisms in nature
a. May occupy transient, dynamic microenvironments
34. Which of the following is an example of predation
e. Myxococcus xanthus cells work together to lyse E. coli colonies
35. Which of the following is in the correct order from earliest evolved to most recently evolved
c. methanogens, anoxygenic phototrophs, oxygenic phototrophs
36. Endomycorrhizal fungie.
e. Cannot be cultured in pure culture
37. Leguminous plants use ____________ to protect nitrogen-fixing symbionts from oxygen.
38. The electron transport chain in a Nitrogen-fixing bacteroid on a leguminous plant uses _______ as a terminal electron acceptor
39. The adult human microbiome is dominated by
a. Firmicutes and Bacteroidetes
40. Which of the following influences the establishment of the human gut microbiome
e. All of the above (Breastfeeding, Human genetic factors, Hygiene habits, Antibiotic use
1. Which of these enzymes is directly involved in transcription?
b. RNA polymerase
2. This picture is showing _______ in the ______ orientation (top to bottom
c. RNA sequence; 5'-3'
When the following fragment of DNA is replicated, what nucleotides would be synthesized?
5' AATGCCC 3'
5' GGGCATT 3'
4. An organism with a frameshift mutation in primase would not be able to
a. Replicate DNA
5. DNA replication in eukaryotes differs from bacteria because
There are more origins of replication per chromosome in eukaryotes than bacteria
6. Which direction is translation occurring in the picture above?
c. Top to bottom (and bottom to top)
7. Which of the following is true of eukaryotic genomes?
b. The gene is the functional unit of genetic information
8. Which of the following is NEVER involved in transcription termination in bacteria?
a. Allosteric inhibition
9. The tRNA anticodon that will be used to initiate peptide synthesis for the following mRNA sequence is______.
5' ...CCAAUGUUU... 3'
d. 3' UAC 5'
10. Which is NOT included in a eukaryotic genome?
d. Chromosomes from associated microbiome
11. Which word best explains why how the codon table is degenerate (having more than one codon per amino acid)?
12. Which of the following elements is NOT important for transcription in bacteria?
d. Ribosome Binding sequence
13. MetJ is a protein that binds S-Adenosyl methionine (SAM) which is a product in the biosynthesis of methionine. When SAM is bound to MetJ, MetJ binds the operator to stop transcription of methionine biosynthetic genes. This is an example of
b. Negative regulation
14. Which of the following is true about the lac operon in the presence of lactose and glucose?
e. Allolactose will still be bound to LacI
15. Which of the following is used to translocate unfolded proteins into or across the plasma membrane
16. Which of the following is NOT true about amino acids
e. Proteins may contain up to 64 known types of amino acids
17. Which of the following is NOT involved in regulating the lac operon?
a. A sensor kinase
18. Which of the following is a regulatory strategy used by eukaryotes?
c. Small RNA
19. A small RNA regulates multiple ABC transporter gene products by binding near the ribosome-binding site. This is an example of
b. Translational regulation
20. In the presence of excess tryptophan
e. Transcription would prematurely stop because a terminator would form in the beginning of the mRNA transcript
21. If aflatoxin, a base-analog mutagen, were used in the Ames test, the result would likely be
a. An increase in histidine prototrophs
22. If aflatoxin targeted the third nucleotide in a codon, it would often cause a _________ mutation leading to a ____________.
c. point; silent phenotype
23. The core genome of all E. coli species would likely contain _______ and be _________ the pan genome of all bacteria.
a. Genes encoding ribosomes; Smaller than
24. Which process is least likely to involve RecA?
25. Generalized transduction
a. May transfer host DNA from any part of the chromosome to a recipient cell
26. What mechanism DOES NOT protect cells against foreign DNA
27. Spontaneous mutations
e. Can be repaired by proofreading or mismatch repair mechanisms
28. Which vector is the best one to use to express genes in two different domains
d. A shuttle vector
29. Which is true about conjugation?
c. Single-stranded DNA crosses from donor to recipient
30. The 16S rRNA gene was amplified by PCR from 2 organisms and the DNA was separated by agarose gel electrophoresis (from top to bottom). What can be concluded from the results below?
d. The 16s rRNA gene is smaller than 3000 bp
31. Which enzyme is NEVER used in cloning?
d. Cas proteins
32. Which of the following is LEAST likely to cause problems when expressing a human gene in E. coli?
d. Getting the right DNA polymerase
33. Which of the following would be easiest to clone and express from an expression vector in E. coli? The size of the genes involved in these processes are shown in parenthases
a. The lacI gene (1 kb)
34. Predicted bacterial ORFs are identified computationally using all of the following EXCEPT
b. Inverted repeats at the start of the gene
35. Which of the following is a way to regulate protein activity in E. coli?
a. Covalent modification
36. Gene expression from a mixed microbial population is best assessed using
d. Next-generation sequencing
37. qRT-PCR never involves
38. Which of the following things contribute to the dynamic nature of microbial genomes?
c. Genomic islands
39. New genetic alleles are NEVER generated by
b. Genotypic reversion
40. Why is the lacZ gene used in cloning?
a. Successful clones form white colonies
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