ICA Questions Flashcards
Which statement about glycolysis is correct?
- Two net molecules of ATP are produced through substrate-level phosphorylation
- A proton gradient is established across the mitochondrial membrane
- Three molecules of NADH2 and one molecule of FADH2 are produced
- Glycolysis cannot proceed under anaerobic conditions
Two net molecules of ATP are produced through substrate level phosphorylation
Which of the following is NOT true of glycolysis?
- It produces 4 net ATP
- It requires an input of ATP to begin
- It occurs in the cytoplasm
- It produces NADH
It produces 4 net ATP
C. perfrings is an obligate anaerobic bacterium unable to survive in the presence of oxygen.
Which of the following enzymes will NOT be found in C. perfrings that you would normally find in an aerobic bacteria?
Superoxide dismutase and Peroxidase
Which of the following is NOT correct with respect to the redox pair NAD+/NADH?
- NADH can accept electrons from an electron transport system
- The reduced, nonaromatic ring of NADH is at a higher energy than the aromatic ring of NAD+
- The nicotinamide ring is heteroaromatic because it has a noncarbon atom is the 4th position
- The nicotinamide ring is a relatively stable aromatic structure
NADH can accept electrons from an electron transport system
You feed E. coli 3 glucose molecules. How many ATP are created ONLY using glycolysis?
6
Fermentation can be defined as?
Partial breakdown of organic food without the use of an electron transport system
Which of the following fermentation processes is responsible for making bread?
Ethanolic fermentation
Which is not an end product of fermentation?
Pyruvate
Microorganisms play an active role in the formation different kinds of products from fermentation. Which one of the following is mismatched?
- Ethanolic fermentation – ethanol and CO2
- Homolactic fermentation – lactic acid and CO2
- Heterolactic fermentation – lactic acid, ethanol and CO2
- Mixed acid fermentation - multiple acids and H2 and CO2
Homolactic fermentation - lactic acid and CO2
Fermentation produces more energy than anaerobic respiration.
FALSE
Methyl red positive tube contains more acids than a phenol red positive tube.
TRUE
The TCA cycle is capable of generating which of the following products from oxidation of each acetyl-CoA molecule
2 carbon dioxide molecules, 3 NADH, 1 FADH2, and 1 ATP
How many electron carriers in total are created from just the TCA from 2 glucose molecules?
16
You feed E. coli 3 glucose molecules. How many ATP are created ONLY through substrate level phosphorylation?
12
Cells can catabolize acetate or fatty acids using a modified TCA called glyoxylate shunt shown below.
Which of the following is NOT TRUE about glyoxylate shunt?
- It produces less CO2 than a TCA
- It produces more NADH than TCA
- It gets activated when glucose is absent or in less amount
- It produces less NADH than a TCA
It produces more NADH than TCA
An unknown bacterium can be tested for fermentation of lactose to mixed acid byproducts such as malic acid and succinic acid through which of the following tests?
Methyl Red test
Rank according to ATP yield, from high to low.
1. Fermentation
2. Aerobic respiration
3. Anaerobic respiration
2,3,1
Which of the following statements about anaerobic respiration is FALSE?
- It yields equal amounts of ATP when compared to aerobic respiration
- It yields lower amounts of ATP when compared to aerobic respiration.
- The complete Krebs cycle is utilized
- It does not involve the ETS
It yields equal amounts of ATP when compared to aerobic respiration
E. coli ETS includes which of the following components.
NADH oxidoreductase, Terminal Oxidase, and Mobile electron carrier
E. coli produces __________ ATP by substrate level phosphorylation and ___________ ATP from oxidative phosphorylation from 1 glucose.
4, 34
Which of the following is NOT true about mitochondrial ETS.
- Mitochondrial ETS pumps 12 H+ per NADH, 2 more than E. coli
- Mitochondrial ETS can produce ATP with out the use of ATP synthase
- Possess an intermediate cytochrome oxidase complex
- Mitochondrial ETS is capable of producing more proton motive force when compared with E. coli ETS per every glucose molecule
Mitochondrial ETS can produce ATP with out the use of ATP synthase
You encounter a previously unknown organism in a sample of seawater. Observing this organism under the microscope, you observe the following:
An intricate internal membrane system
Linear chromosomes
DNA sequence reveals that its genome is made of 4 types of nucleotides (A, T, C and G).
DNA sequence reveals that much of the genome of this organism does not code for protein.
What kind of organism is this?
Eukaryote
You encounter a previously unknown organism in a sample of seawater. Observing this organism under the microscope, you observe the following:
An intricate internal membrane system
Linear chromosomes
DNA sequence reveals that its genome is made of 4 types of nucleotides (A, T, C and G).
DNA sequence reveals that most of the genome of this organism does not code for protein.
Based on your answer to the previous question? How did you determine the type of organism?
Presence of internal membrane systems, most of the genome of this organism does not code for protein, and linear chromosomes
Now imagine that you have isolated a genomic sequence of an unknown organism from seawater but do not have any cells that you are able to observe or culture. The genome exists as two separate pieces of DNA that have their genes placed in functional groups and have relatively little intergenic (non-coding) DNA.
What kind of organism is this?
Bacterium, Archaeon, or Prokaryote
Now imagine that you have isolated a genomic sequence of an unknown organism from seawater but do not have any cells that you are able to observe or culture. The genome exists as two separate pieces of DNA that have their genes placed in functional groups and have relatively little intergenic (non-coding) DNA.
You discover that the smaller of the two pieces of DNA contains several genes involved in the hydrolysis (metabolism) of glucose.
Is this more likely to be a plasmid or a chromosome or both?
Chromosome
Now imagine that you have isolated a genomic sequence of an unknown organism from seawater but do not have any cells that you are able to observe or culture. The genome exists as two separate pieces of DNA that have their genes placed in functional groups and have relatively little intergenic (non-coding) DNA.
You discover that the smaller of the two pieces of DNA contains several genes involved in the hydrolysis (metabolism) of glucose.
How do you know if is it a plasmid or a chromosome or both?
It contains genes involved in the metabolism of glucose which are essential to the cell
Which of the following will be observed in a bacterium that lost its ability to make DNA ligase.
You will find many small fragments of DNA in the cytoplasm of the bacterium
Which of these represents a correct order of proteins involved in bacterial DNA replication?
DnaA → primase → DNA pol III → ligase
Which of the following is NOT true when it comes to Bacterial DNA Replication.
- Replication in bacteria begins only from one location in the chromosome
- Replication is bidirectional
- It is semiconservative
- It requires only one set of DNA polymerase
It requires only one set of DNA polymerase
You isolate a piece of DNA from a microorganism you cultivated from your teeth. The piece of DNA is 94 kbp in size and is circular. You sequence it and discover that it contains genes for pili, and antibiotic resistance. What is this piece of DNA?
plasmid
All of the following are required in a PCR reaction EXCEPT
- DNA template
- DNA polymerase
- DNA ligase
- Primers
DNA ligase
Which of the following is/are TRUE about PCR.
- It requires DNA polymerase
- It requires heating
- It required DNA ligase
- It requires DNA primers
- It involves Okazaki fragments
It requires DNA polymerase, heating, and DNA primers
The necessary ingredients for PCR reactions are mixed together in a test tube. The DNA polymerase is from Thermus aquaticus, and the DNA template is from an E. coli. The newly synthesized DNA would look like _____.
E. coli DNA
Taq DNA Polymerase is commonly used in Polymerase Chain Reaction (PCR) because:
It functions in high temperature environments
You are a public health official investigating an outbreak of Salmonella. To detect current cases you choose to examine patients blood for the ____________ antibody class.
IgM
In adaptive immunity, the term “clonal selection” best refers to the
ability of specific B-cell subsets to proliferate and produce antibodies upon exposure to a specific epitope.
Which of the following statements about MHC class II molecules are true?
- They are found only on antigen presenting cells
- They present extracellular antigens.
- They are found on all nucleated cells.
- They are found on the surface of most pathogens
They are found only on antigen presenting cells and present extracellular antigens
An immune deficiency causes a severe reduction in the amount of MHC-II expressed on the surface of professional antigen-presenting cells. Predict which immune processes will be significantly impacted by this deficiency.
Phagocytosis by macrophages, antibody production, and cell killing by cytotoxic T cells
Which of the following can be used to make vaccines?
Purified components of microorganisms, Killed microorganisms, Live microorganisms, and mRNA that codes for an antigen
Innate immunity involves all of the following host defenses EXCEPT
- production of antibodies to bind specific pathogen proteins.
- production of small peptides that destroy the bacterial membrane.
- engulfment of microbes by phagocytes.
- secretion of mucus to prevent microbial entry.
production of antibodies to bind specific pathogen proteins
Opsonization is a process whereby innate and adaptive immunity work together to
phagocytize an invader
Which body sites are colonized by normal microbiota?
- Lungs
- Kidneys
- Small Intestine
- Stomach
- Urinary bladder
Lungs, small intestine, stomach, and urinary bladder
Under what circumstances can microbiota cause disease?
- If other normal flora microbes are reduced or eliminated, as with antibiotic treatment
- Can cause disease when they accidentally penetrate beyond their normal flora sites
How do the lungs avoid being colonized by pathogens?
- The lungs are also protected by alveolar macrophages that ingest and kill pathogens that make it past the ciliary elevator.
- By using a mechanism called the mucociliary escalator to avoid being colonized
A man has been taking excessive amounts of antacids for heartburn. Which innate defense mechanism might be altered by his actions?
increase in the pH of stomach acid and exposes himself to more GI tract infection
Match Type III Secretion system with the organism that utilize for their pathogenesis
Salmonella species
Match Type IV Secretion system with the organism that utilize for their pathogenesis
Bordetella pertussis
Thick polysaccharide capsules are important virulence assets for which of the following species?
Neisseria meningitidis and Sptreptococcus pneumonia
Streptococcus pyogenes virulence factors
M protein
Staphylococcus aureus virulence factors
Alpha toxin, Toxic shock syndrome toxin, Exfoliant toxins A & B, and Protein A
E. coli O157:H7 virulence factors
Shiga-like toxin
Streptococcus pneumoniae virulence factors
Capsule
Mycobacterium tuberculosis virulence factors
Multi drug resistance
S. aureus disease
Scalded skin syndrome
Y. pestis disease
Bubonic plague
P. falciparum disease
Cerebral malaria
T. palladium disease
syphilis
S. pyogenes disease
Necrotizing fasciitis
All of the following are good indications of a pathogenicity island in a microbial chromosome EXCEPT
- GC/AT ratio higher or lower than the rest of the chromosome.
- presence of clusters of virulence genes
- residual phage genomes flank the island.
- presence of RNA nucleotides
Presence of RNA nucleotides
The alpha toxin of Staphylococcus aureus have similar effect on human cells as the antibiotic _______ on gram negative bacteria.
Gramicidin
Based on your knowledge of microbial genetics and microbial pathogenesis, where do you think the genetic information for endotoxins are located?
Chromosomes
Based on your knowledge of microbial genetics and microbial pathogenesis, where do you think is/are the likely location/s of the genetic information for E. coil shiga exotoxins?
Plasmids, chromosomes, and phage genome
Consider an MIC result of 5 μg/ml of penicillin for bacterial strain A, 25 μg/ml for strain B, 15 μg/ml for strain C, and 20 μg/ml for strain D. Which bacterial strain can be interpreted as the most resistant to penicillin?
B
Consider a mutation in which the change is from UAC to UAG. Which type of mutation is this?
Nonsense mutation
You inoculated 100 bacteria A, with a generation time of 20 minutes, into 100 ml of nutrient broth. At the same time, you inoculated 100 bacteria B with generation time of 20 minutes into 200 ml of nutrient broth. After incubation for 24 hours, if all cells divide by binary fission and remain viable in log phase, you can reasonably expect to have
The same number of cells in both cultures
You inoculated 100 bacteria A, with a generation time of 20 minutes, into 100 ml of nutrient broth. At the same time, you inoculated 200 bacteria B with generation time of 20 minutes into 200 ml of nutrient broth. After incubation for 24 hours, if all cells divide by binary fission and remain viable in log phase, you can reasonably expect to have
More bacteria B in the 200mL
C. botulinum is an aerotolerant anaerobic bacterium able to survive in the presence of oxygen with the help of certain metabolic antioxidants.
Which of the following enzymes would you expect to find in C. botulinum that you would not find in a strict anaerobe?
superoxide dismutase
Serial dilutions can be used to estimate the total number of ONLY living bacteria not dead bacteria.
TRUE
One cell with generation times of 60 minutes are inoculated into a culture medium. How many cells are there after 5 hours?
32
2 bacterial cells with generation time of 20 minutes are inoculated into a culture medium. How many cells are there after 2 hours? (Assuming all cells divide by binary fission in log phase and remained viable).
128
A virus such as influenza virus might produce 800 progeny virus particles from one host cell infected by one virus.
How would you mathematically represent the exponential growth of the virus?
800^n
A cafeteria worker who fails to wash his hands thoroughly and fails to wear gloves inoculates a pie with 4 E.coli cells in when he uses his finger to test whether it is done.
By the time you purchase the pie, there were 128 E.coli cells. How many generations did the cells go through between the initial inoculation and the time you bought the pie? Assuming all cells multiplied in a log phase.
5
A cafeteria worker who fails to wash his hands thoroughly and fails to wear gloves inoculates a pie with 4 E.coli cells in when he uses his finger to test whether it is done.
By the time you purchase the pie, there were 128 E.coli cells. How many minutes it took from the time he touched it until you purchased it? Assuming all cells multiplied in a log phase.
FYI, E. coli have a generation time of 20 minutes.
100
The a part of the lipopolysaccharide (LPS) that is found in the outer membrane of Gram-negative bacteria is also known as _________.
endotoxin
After you run a couple of experiments, you got the following results.
Cell wall = Contains peptidoglycan
Cell membrane type = lipid bilayer
Fatty acid linkage = ester bonds
Cell envelope = contain mycolic acids
What are organism A?
Mycobacterium species
Which arrangement is commonly seen in organisms in the Genus Staphylococcus?
clusters
Student in the lab performs a Gram stain on Staphylococcus aureus, a Gram positive cocci. The student skips the decolorizing step. When the student observes the slide under 100x magnification what do they see?
Assume all other steps were followed properly
Gram positive cocci
A student in the lab performs a Gram stain on E. coli, a Gram negative bacilli. The student skips the decolorizing step. When the student observes the slide under 100x magnification what does the student see at the end of the experiment?
Assume all other steps are followed properly.
Gram positive bacilli
Bacteria and archaea are different in all of the following EXCEPT
- Size and shape
- Cell wall composition
- rRNA sequence
- Cell membrane composition
Size and shape
What is true regarding proteins that are embedded within the cell membrane?
They provide structural support
What are two commonalities between Gram negative and Gram positive cell envelop?
Peptidoglycan and Cell membrane
Calculate the total magnification of the microscope you use in your microbiology lab when using 20X objective lens.
200
Calculate the numerical aperture (NA) of the objective lens shown below if the medium between the objective and sample if air.
Theta = 15 degrees
0.26
An objective lens with a magnification of 40X created an angle of cone of light measured from the center of 30o (see below).
Calculate refractive index (n) of the medium between the tip of the objective and the sample if the NA is 0.67?
1.34
An objective lens with a magnification of 40X created an angle of cone of light measured from the center of 30o (see below).
Name the medium between the tip of the objective and the sample if you calculated the NA to be 0.67 with the given setup above?
Water
If 0.2 μm = 200 nm, 150 μm = ______ nm
150,000 nm
Sari is a microbiology student attempting to identify a microbe that she can study for her senior thesis project. Which of the following headlines refers to a microbe that she might find interesting?
“Brain-eating amoeba strikes two teens in one week”
