Microbiology Final Exam 2020
Free Energy Change
(G) Gibbs free energy reaction = enthalpy - entropy
Enthalpy
(H) change of heat in a system
Entropy
(S) measure of randomness/disorder in a system
Endergonic Reaction
A non-spontaneous chemical reaction in which free energy is absorbed from the surroundings, positive G
Exergonic Reaction
A spontaneous chemical reaction in which there is a net release of free energy, negative G
Which type of transport mechanism would be used to acquire nutrients found in such low concentrations and deliver them inside the cell where they are at higher concentrations?
Active Transport
Who is credited with discovering penicillin when he recognized mold growing on a petri dish and inhibiting bacterial growth?
Alexander Fleming
Which of the following is not found in DNA?
Amino Acids
Phospholipids
Apart of the cell membrane Glycerol with ester links to two fatty acid tails and a phosphoryl head group They phosphoryl head group is polar and the fatty acid tail is non-polar
Consider the structure of a nucleotide, where is the nitrogenous base located?
At the 1' position of the ribose.
Consider the structure of a nucleotide, where is the phosphate group located?
At the 5' position of the ribose.
Which component of an AB toxin is responsible for binding a host cell receptor?
B component
Spores from this bacterium were sent via mail as an act of bioterrorism in the 1990s
Bacillus anthracis
A bacterium lacking a capsule would likely __________.
Be quickly phagocytized by an immune cell.
Which of the following is NOT true of Lyme's disease?
Borrelia burgdorferi has many extracellular flagella.
Which of the following is FALSE concerning the mitochondria and chloroplasts and is not evidence in support of the Endosymbiotic Theory?
Both can survive independently when removed from a eukaryotic cell.
Which of the following scenarios represents natural passive immunity?
Breast feeding a newborn child
Virally infected host cells will present antigen on _______.
CD47 molecules.
Photoorganoheterotrophs
Carbon source: Sunlight Energy source: organic compounds
Which of the following scientists did not help to discredit the theory of Spontaneous Generation?
Carl Woese
Who established the Three Domain System?
Carl Woese
This pathogen causes a sexually transmitted disease that is responsible for over 1.5 million infections in the US. It is one of the leading causes sexually transmitted infertility in women.
Chlamydia trachomatis
A previously healthy 3-month-old girl presented with muscle weakness, bilateral facial weakness, poor feeding, and minimal antigravity movement of the limbs. Her parents confessed of feeding her raw honey. You immediately consider the ingestion of _________ spores.
Clostridium botulinum
Spores from this bacterium are common in hospitals and cause severe inflammation of the colon especially in patients who have had their normal flora wiped out with antibiotics.
Clostridium difficile
How were the Three Domains determined?
Comparison ribosomal RNA (rRNA) nucleic acid sequences
During the _________ period of an infectious disease, the patient begins to feel better and the signs and symptoms of the disease are no longer present.
Convalescence
CD8+ cells are also known as _____.
Cytotoxic T cells
Suppose Pasteur's swan-necked flasks containing boiled broth became cloudy 24 hours after boiling. Which choice could best explain the turbidity or cloudiness in the broth without supporting spontaneous generation?
Endospores in the broth survived boiling and grew after the broth cooled
Photolithoautotrophs
Energy source: Sunlight Carbon source: Carbon Dioxide
Which of the following scientists helped discredit the theory of Spontaneous Generation.
Francesco Redi, Lazzaro Spallanzani, Louis Pasteur
Symbol for Enthalpy (Gibbs Free Energy)
H
What reinforce and stiffen the plasma membrane in bacteria?
Hapanoids
Which scientists demonstrated that DNA directed replication of bacteriophages and supported the hypothesis that DNA was the genetic material of cells?
Hershey and Chase
Which antibody is found in breast milk and is important in natural passive immunity?
IgA
Bacillus anthracis___________.
Is the causative agent of anthrax disease.
MacConkey agar contains bile salts (which inhibit the growth of gram-positive bacteria) as well as lactose and a pH indicator to help identify lactose fermenters. How would MacConkey agar be classified?
It is a differential and selective media.
If you wished to isolate spores from a bacterial culture, which phase of growth would you be able to isolate the most spores from?
Late stationary phase
Gram-positive cell envelopes do NOT include which of the following?
Lipopolysaccharides (LPS)
What is the purpose of the nucleoid in bacterial cells?
Localization and condensation of genetic material
During this phase of the growth curve, there is an increase in cell numbers and a proportional decrease in available nutrients.
Log phase
The minimum amount of an antimicrobial drug needed to inhibit growth of a pathogen is referred to as the _____.
MIC
The minimum amount of an antimicrobial drug that kills a pathogen is referred to as the _____.
MLC
What did the Miller-Urey experiment demonstrate?
Macromolecules could be formed from early earth like conditions.
Extreme thermophiles live at very high temperatures. Which membrane composition would they likely have?
Membranes composed of longer saturated fatty acid tails
Which of the following about microbes is FALSE?
Microbes include members of two of the three domains of life.
The primary function of the bacterial flagella is?
Motility
Can ALL bacteria form biofilms?
No, due to lack of motility
Which of the following correctly ranks a point mutations effect on a protein from most severe mutation to the least?
Nonsense, missense, silent
Beta-lactamase producing organisms would be resistant to which of the following antibiotics?
Penicillin
Gram-negative cell walls contain
Peptidoglycan, LPS, endotoxin
Which of the following molecules can donate a phosphate to ADP to make ATP via substrate-level phosphorylation?
Phosphoenolpyruvate
Chemotaxis
Process by which bacterial cells sense a chemical attractant/repellent and move towards/away from it.
Bacteria & Archaea
Prokaryotic architecture
Membrane embedded _________ help with both active and passive transport across the membrane.
Proteins
The macromolecule that is found in greatest abundance in the bacterial cytoplasm is:
Proteins
Which of the following are found in bacterial membranes?
Proteins, phospholipids, hopanoids
Gram-positive bacterial cells stain ______ because
Purple, the primary dye crystal violet is complexed with the iodine and is trapped in the large peptidoglycan layer
The development of the "RNA World" hypothesis is supported by the discovery of _______.
Ribozymes which are RNA molecules that have enzymatic activity.
The first person to develop a compound microscope with a 30X lens was?
Robert Hooke
The food borne disease Typhoid fever is cause by ingesting food contaminated with _______.
Salmonella Typhi
Which of the following types of molecules transport into and out of the cell via simple diffusion?
Small uncharged molecules such as carbon dioxide
Which food are you least likely to find in Dr. Danny Unruh's refridgerator?
Sprouts, he won't eat sprouts due to the fact that they can harbor unsafe bacteria.
The pathogen most associated with strep throat is ________.
Streptococcus pyogenes
Microbiology
Study of microorganisms
Which of the following is TRUE regarding AB toxins?
The B portion of the AB portion is the binding subunit of the toxin.
Which of the following statements about bacterial growth is FALSE?
The bacterial cell cycle includes both a G1 and G2 phase.
Bacteria use quorum sensing to directly determine _______.
The density of the population of bacteria within the environment.
Postulate 1
The microorganism must be present in every case of the disease but absent from healthy organisms
Postulate 3
The same disease must result when the isolated microorganism is inoculated into a healthy host
Paul Erlich had a library of organoarsenic compounds to fight against the syphilis causing pathogen Treponema pallidum. He described his cure as a "magic bullet". What was he eluding to?
The selective toxicity of his compound against Treponema pallidum rather than the host tissue.
Postulate 2
The suspected organism must be isolated, grown in pure culture
Substrate-level phosphorylation
The synthesis of ATP from ADP by phosphorylation coupled with the exergonic breakdown of a high-energy organic substrate molecule.
Penicillin blocks the _____________ from crosslinking the _________.
Transpeptidase, peptidoglycan (cell wall)
AB toxins have a binding domain that can attach to the host cell receptor and an enzymatic domain that enters the cell and causes toxicity, true or false?
True
The human body is a microbial ecosystem containing more bacterial cells than human cells, true or false?
True
Which form of growth control causes the formation of thymine dimers in the DNA of microbes?
UV irradiation
What could be a condition that causes the formation of an endospore?
UV radiation, high temperatures, low nutrients harsh conditions
A mutant deficient in DNA polymerase I ___________.
Would have nucleotides missing between Okazaki fragments where the RNA primer once was located.
What is a capsule composed of?
carbohydrates
Secondary active transport
couples potential energy of ion gradients transport substances without modifying them
Mechanical Work
energy cell motility, movement structures within cells
Transport Work
energy take up nutrients and eliminate wastes, maintain ion balance
Eukarya
eukaryotic architecture, multicellular
Exponential Phase
growth curve of microbial population is constant, maximum rate
Primary active transport
mediated carriers use energy by ATP hydrolysis to move substances against gradient without modifying them
Extremophiles
microbes that grow under harsh/extreme conditions
Mesophiles
moderate temperatures, optimum 20oC-45oC
Passive (simple) diffusion
molecules move one region of higher concentration to lower concentration
Death Phase
number of viable cells decline exponentially, dying constant rate
Acidophiles
optimum growth pH 0-5.5
Psychrophiles
optimum temperature below 15oC; capable of growth at 0oC, maximum 20oC
Microorganisms
organism too small to be seen by naked eye, often unicellular, if multicellular, low degree differentiation
Neutrophiles
pH 5.5-8.0
Alkaliphiles
pH 8.0-11.5
Lag phase
period after introduction of microorganism into fresh culture medium, no increase cell numbers
Stationary Phase
population growth ceases, growth curve levels off, caused by nutrient limitation
Biochemical pathways
sets of chemical reactions performed by organisms that convert a starting substrate into one or more products
Facilitated diffusion
substance move across membrane with assistance transport protein channels and carriers
Chemical Work
synthesis of complex biological molecules from simpler precursors, energy increase molecular complexity
Postulate 4
the same microorganism must be isolated again from the diseased host