Microbiology Final
two ATP or GTP molecules
The TCA cycle generates all of the following from each acetyl-CoA molecule oxidized except ________.
a modification of the endosymbiotic hypothesis
Match the following terms with their definitions: hydrogen hypothesis
contains only one species of bacteria
Match the following terms with their definitions: pure culture
promotor
A bacterial _____________ is the nontranscribed region of the DNA to which the sigma factor of RNA polymerase binds in order to initiate transcription
PEP inactivates the enzyme phosphofruktokinase, an enzyme that acts early in glycolysis. This is an example of feedback inhibition
A buildup/excess of the *almost* final product of glycolysis, phosphoenol pyruvate (PEP) will ultimately result in the glycolysis being halted. How is it that PEP accomplishes this?
Holoenzyme
A complete enzyme that consists of a protein component and a nonprotein component is called a(n) _______________.
a strictly anaerobic protist
A hydrogenosome would most likely be used by:
photolithoautotroph
A newly described bacterial species has been shown to use CO2 as its carbon source. Its energy source is light, and its source of reducing power is water. Which term would best describe this nutritional type?
Endergonic
A reaction that requires an input of energy in order to proceed is:
viral encoded RNA-dependent-RNA polymerase
A single stranded RNA virus would require the use of this enzyme to make copies of its genome (note-- this does not include HIV)
eukaryotes (photosynthetic protist/algae)
A student is observing microorganisms in a sample of pond water. One organism of interest has an obvious nucleus, small oval structures containing a green pigment, and does not appear to be motile. In which of the following groups would this microbe most likely be classified?
Is termed a prophage Integrates its DNA into the host's genome
A temperate phage who is currently in the lysogenic lifecycle:
16.0
According to the results of the dilution susceptibility testing method shown below, what is the minimum LETHAL concentration (MLC) of the drug?
c. either there is a balance between cell division and cell death or there is a cessation of cell division even though the cells may remain metabolically active
According to the work accomplished to make the chart below, it is thought that the total number of viable microorganisms remains constant in stationary phase because ________.
Both transcription and translation are part of the central dogma which entails turning DNA to RNA to Protien. Trancription is the process in which DNA is turned to RNA whereas translation is the process in which RNA is made into protien. Both transciption and translation are three step processes; initiantion, elongation, and termination. Transcription does not require a primer to start whereas translation does require a primer for initiation.
Both Hfr conjugation and F' conjugation are transefer of genetic information from one live cell to another live cell aka conjugation. Hfr conjugation tries to replicate and transfer the entire chromome of the donor cell whereas F' conjucation transfers a plasmid that has seperated from the donor cells chromosme Both Hfr conjugation and F' conjugation do not complete trasfer the F factor gene which carries the gentic code for the sex pilus and the ability to repoduce. Hfr conjugation replicated in a high frequency but take around 100 minutes and is cut off before complete transfer whereas F' conjucation uses rolling circle replication of its plasmid which contains part of the genetic information from the donor cells chromosome.
4/12 = 0.33
Calculate the evolutionary distance between organism 1 and 4.
Noncyclic photophosphorylation: Light is absorbed at 680 nm and 700 nm Active in the production of NADPH Includes the oxidation of water to release oxygen Cyclic photophosphorylation: A single photosystem functions independently of Photosystem II Produces ATP, but not NADPH electrons return to the reaction center from which they orginated
Categorize the following traits of each type of photophosphorylation: A single photosystem functions independently of Photosystem II Light is absorbed at 680 nm and 700 nm Includes the oxidation of water to release oxygen Produces ATP, but not NADPH Active in the production of NADPH electrons return to the reaction center from which they orginated
Both require energy The Tat system translocates folded proteins whereas the Sec system translocates unfolded proteins The Tat system uses energy from a PMF whereas the Sec system uses hydrolysis of ATP and a PMF Tat recognizes two consecutive arginines in the signal peptide and Sec recognizes hydrophobic signals
Choose the correct similarities and differences between the sec system and the tat system for protein translocation:
the central dogma is that genetic material travels from DNA to RNA through the process of transcription, and RNA to amino acids through the process of translation. no, prions do not obey the central dogma they do not obey the central dogma because the shape of the protein changes from alpha helices to beta sheets without a change in the DNA sequence.
Define the central dogma. Do you believe that prions obey the central dogma? Why or why not?
Both of these events occur in bacteria that live in the soil. Denitrification is the process of reducing Nitrate into N2 gas, whereas nitrification is the process of oxidizing ammonia into nitrate. Denitrification produces harmful compounds such as nitrous oxide whereas nitrification does not.
Denitrification vs. Nitrification
secondary active transport
Escherichia coli is a Gram-negative organism that utilizes the sugar lactose as a source of energy. E. coli employs the use of lactose permease, a protein that couples a H+ (proton) gradient as the driving force to get lactose into the cell. Which type of transport is this?
Ratio of ATP to NADPH required is 3:2 Noncyclic photophosphorylation makes 1 ATP and 1NADPH per cycle. After 2 rounds of noncyclic photophosphorylation, there would be 2 ATP and 2NADPH made. But we still need 1 more ATP. In order to make 1 more ATP without also making 1 NADPH, cyclic photophosphorylation would allow the organism to do so, because it only produces ATP, not NADPH.
Explain why an organism would want to use only one photosystem vs. both photosystems in oxygenic photosynthesis, relating to the following equation:
ATP has a massive phosphate transfer potential because the three phosphate groups are all negatively charged, and next to eachother, which creates tension in the molecule (all of those negative charges are attempting to repel eachother). Therefore, when one of the phosphates is released, this relieves pressure on the molecule and releases a ton of energy!
Explain why the breakdown of ATP is such a fantastic source of energy to couple to endergonic reactions.
Shifts the reading frame of the mRNA sequence Are caused by insertions/deletions of one or two nucleotides
Frameshift mutations..
Lab grown bacteria have it much easier! We can keep them at their optimal temperature with plenty of moisture, and provide all the nutrients they need in the media we grow them on. There is not as much competition, so cells may be larger than what we'd see in the wild.
Give two reasons that growth cycles are different in laboratory conditions vs. in the "wild"?
is observed when single cells move independently does not involve flagella, but type IV pilus
Gliding motility: (select all that apply)
Factors that bind to host cells
Glycoprotein spikes protruding from the outer surface of viral envelopes function as _______.
Both Hfr conjugation and F' conjugation are transefer of genetic information from one live cell to another live cell aka conjugation. Hfr conjugation tries to replicate and transfer the entire chromome of the donor cell whereas F' conjucation transfers a plasmid that has seperated from the donor cells chromosme Both Hfr conjugation and F' conjugation do not complete trasfer the F factor gene which carries the gentic code for the sex pilus and the ability to repoduce. Hfr conjugation replicated in a high frequency but take around 100 minutes and is cut off before complete transfer whereas F' conjucation uses rolling circle replication of its plasmid which contains part of the genetic information from the donor cells chromosome.
Hfr conjugation vs. F' conjugation
The host cell degrades and lyses, allowing the virions to escape
How do naked viruses exit their host cell?
Nucleic acid injection through the plasma membrane
How does a bacteriophage gain entry to their host cell?
the viral DNA contains short terminal repeats that fold the DNA onto itself, creating a free 3'OH for replication
How does a negative sense single stranded DNA virus such as Parvovirus "trick" the host into replicating its genetic material?
1.87 X 10^ 23 ATP
How much ATP could Saccharomyces cerevisiae synthesize if it oxidized 14 grams of sugar, via substrate level phosphorylation only? Hint: The molecular weight of glucose is 180 g/mol Avogadro's number = 6.022 X 1023
14%
If 14% of nucleotides in the DNA of a particular organism contain cytosine, estimate the percentage of guanine that is present in the DNA.
Bind to the allosteric site of the enzyme Change the active site of the enzyme upon binding to the allosteric site
In allosteric regulation, effector molecules usually:
the araC gene codes for a regulatory protein-- when arabinose is in the media, the GFP is turned on. When it's not, the GFP gene is turned off. this is an example of direct selection because the ampicillin will kill the cells that did not take up the plasmid. The only cells that will grow on the plate are the ones that contain it.
In regard to the pGLO plasmid:
Electrons flow from NADH to O2 because NADH has the most negative reduction potential and O2 the most positive with electron carriers in between, each becoming more positive to direct the electron flow
In the electron transport chain, why do electrons flow in one direction from NADH to O2 rather than the reverse direction, or randomly?
water is split to form oxygen gas electrons from water flow through electron transport chains resulting in synthesis of ATP and NADPH photosystems I and II are both required.
In the process of noncyclic photophosphorylation, ________.
NADH; pyruvate
In this redox reaction involving NAD/NADH and pyruvate, ________ is oxidized and ________ is reduced.
Water, CO2, ATP
Indicate the final products of aerobic respiration.
The result of an exposure to a known mutagen
Induced mutations are...
amphipathic
Lipids with polar and nonpolar ends are said to be ________.
-HIV uses reverse transcriptase which is highly error prone, leading to rapid evolution of the virus -undiagnosed cases of HIV are more common than many other viral illnesses because it can take years for symptoms to show up -HIV integrates into the host cell genome, so to target HIV thoroughly, we would need to target the host. Not ideal.
List and describe two reasons why HIV has proven so difficult to find a cure or vaccinate for.
Louis Pasteur hypothesized that spontaneous generation was untrue-- that living organisms do not just spontaneously "show up." He disproved the theory of spontaneous generation by exposing two swan necked flasks to the open air-- one whose neck was broken, and one whose neck was intact. The broth in the flask with the broken swan neck became cloudy (indicating bacterial growth), whereas the one with the intact neck did not. It was suspected that the one with the broken neck was better exposed to microbes in the air, whereas the one with the intact neck collected the bacteria in the neck, blocking their entry to the broth. If spontaneous generation was occuring, both broth samples should have grown bacteria.
Luis Pasteur carried out a series of experiments as depicted by the image below. 1) What did he hypothesize? 2) Did he prove or disprove his hypothesis? 3) Explain your answer to 1 & 2.
Gram Negative: Contains outer membrane Large periplasmic space Few layers of peptidoglycan Contains lipopolysaccharides Gram Positive: Small periplasmic space Many layers of peptidoglycan Contain teichoic & lipoteichoic acids
Match the correct traits to the correct category: Small periplasmic space Contains outer membrane Many layers of peptidoglycan Large periplasmic space Contain teichoic & lipoteichoic acids Few layers of peptidoglycan Contains lipopolysaccharides
responsible for presence O2 gas in earth's atmosphere
Match the following terms with their definitions: Cyanobacteria
evidence of microbial plasma membranes
Match the following terms with their definitions: Hopane
the organism from which all other organisms have evolved
Match the following terms with their definitions: LUCA
the idea that microbes cause disease
Match the following terms with their definitions: germ theory
storage inclusion: sulfur globule microcompartment: carboxysome gas vacuoles: aquatic bacteria magnetosomes: orient bacteria via attraction to Earth's core
Match the following terms: storage inclusion, microcompartment, gas vacuoles, magnetosomes
1. replication fork 2. lagging stand 3. leading strand 4. RNA primer 5. helicase 6. DNA ligase 7. DNA polymerase
Match the number on the diagram with the correct term relating to DNA synthesis.
Passive diffusion: Concentration gradient Facilitated diffusion: Aquaporins Secondary active transport: Hitching a ride with a sodium pump Group translocation: Phosphoenolpyruvate: sugar phosphotransferase system (PTS) Primary active transport: ATP-binding cassette (ABC) transporters
Match the transport mechanism to the appropriate example: Passive diffusion, Secondary active transport, Group translocation, and Primary active transport
Endocytosis
Naked viruses gain access to their host cell by:
phosphodiester, hydrogen
Nucleotides next to one another on a strand of DNA are bound by __________ bonds, whereas nucleotides "across" from one another on the strand are bound by _________ bonds.
Plant releases molecules called flavonoids Flavonoids taken up by bacteria and bind to the protein NodD to activate the production of Nod factors Nod factors result in the plant root hairs to curl which traps the bacteria. An infection tube is formed for the bacteria to enter the plants Rhizobium is then able to fix nitrogen which is beneficial for the plant and bacteria
Place the events of communication that occurs between rhizobia and their plant hosts in the correct order.
often give a selective advantage to the bacterium are often a source of antibacterial resistance genes are often circular pieces of genetic material that are not part of the chromosome in combination with the chromosome is called the genome
Plasmids (select all that apply):
they do not have a cell wall
Pleomorphic microorganisms can also be described as "shape-shifters." What is the reason that Mycoplasma bacterial species fit into this category?
Both Prokaryotic and Eukaryotic structures contain cytoplasm Eukaryotic cells contain membrane-bound organelles Whereas Prokaryotic cells do NOT contain membrane-bound organelles Prokaryotes have a simple structure and store their DNA in their nucleoid Whereas Eukaryotic cell's membranes have a more complex structure and store their DNA in their nucleus
Prokaryotic cell structure vs. eukaryotic cell structure
Mitochondria and chloroplasts have their own DNA and ribosomes. Peptidoglycan is found within the membranes of chloroplasts and algae. Small subunit rRNA analysis shows that mitochondria and chloroplasts are related to bacteria.
Select the evidence that supports the endosymbiotic hypothesis.
The goal of fermentation is to regenerate NAD+ so that glycolysis can keep running in order to make ATP. The reason that we want to regenerate NAD+ is because in the process of fermentation, there is no oxygen to act as an electron acceptor in the ETC, so the ETC gets shut down, and there goes the ability to make ATP via oxidative phosphorylation. Therefore, the only way that ATP can be made is through glycolysis, which means we need NAD+ to pick up electrons that are generated from the oxidation of glucose so that ATP can continually be synthesized.
State the goal of fermentation in your own words, including the conditions under which fermentation occurs.
true
T or F: A chemical reaction with a delta G of -686 kJ/mol is considered exergonic.
true
T or F: A chemolithoautotroph could use CO2 as its carbon source and be capable of fixing that carbon into methane gas, CH4.
True
T or F: A psychrophilic (cold loving) microorganism would adjust to a temperature change from 0°C to 9°C by increasing the ratio of saturated fatty acids in its cytoplasmic membrane.
true
T or F: A substrate may be converted to a product by more than one enzyme, but enzymes are "monogamists"—that is, their active site is specific to their substrate.
False: A temperate phage will deintegrate from its host cell if the host cell is in danger.
T or F: A virulent phage will deintegrate from its host cell if the host cell is in danger.
False: positive sense RNA, will not be able to negative sense RNA, i.e., RNA that is oriented 3'--5' cannot be translated directly because it does not look like mRNA and therefore the host does not know it's supposed to translate it. Before it can be translated, it must first be copied into positive sense RNA (5'--3') by the viral-encoded RNA dependent RNA polymerase!
T or F: A virus with negative sense RNA will be able to have its nucleic acid directly translated into protein.
True
T or F: ABC transporters take part in a type of active transport that move a single molecule across the membrane while using energy in the form of ATP.
False: Eukaryotic flagella move from base to tip, whereas bacterial flagella move like a propellor., Bacterial flagella move like a propellor, whereas prokaryotic flagella move from base to tip.
T or F: Eukaryotic flagella move like a propellor, whereas bacterial flagella move from base to tip.
False: Gram positive cells are negatively charged.
T or F: Gram positive cells are positively charged.
true
T or F: In a Winogradsky column, sulfur concentrations are highest at the bottom of the bottle or cylinder.
False: noncylic photophosphorylation, In cyclic photophosphorylation, NADPH is not synthesized
T or F: In cyclic photophosphorylation, NADPH is synthesized to eventually be consumed in the process of carbon fixation.
True
T or F: In eukaryotes, a ubiquitin tag is added to misfolded proteins to target them to the proteosome.
True
T or F: Influenza is an example of a zoonotic viral infection because it can jump from birds to humans.
True
T or F: Lactose acts as an inducer of the lac operon, binding the repressor protein to allow for transcription of the structural genes of the Lac operon.
False: NADH is less likely to hold onto its electrons than H2O
T or F: NADH is more likely to hold onto its electrons than H2O
False: Oxygen is not always required for the regeneration of NAD+ from NADH., Oxygen is not required for fermentation, fermentation
T or F: Oxygen is always required for the regeneration of NAD+ from NADH.
True
T or F: Peptidoglycan is an excellent target for antibiotics because this is a structure that only bacteria possess.
False: Persisters are resistant to antibiotics because they have stopped growing and therefore the target of the antibiotic is likely inactive.
T or F: Persisters are resistant to antibiotics because they carry a gene in their plasmid that codes for it.
True
T or F: Reduction of nitrate by Paracoccus denitrificans is harmful to soil health.
False: Rhinovirus is considered an acute virus.
T or F: Rhinoviruses, an agent that can cause the common cold, would be considered a persistent virus.
False: Sulfonamides have a relatively high therapeutic index because they target folate synthesis in bacteria
T or F: Sulfonamide drugs have a relatively low therapeutic index because they target folate synthesis in bacteria.
True
T or F: The following reaction shows how amino acids can be used as a source of energy via transamination and deamination.
True
T or F: The function of an intracytoplasmic membrane in bacteria is comparable to a mitochondrion in an aerobic eukaryotic organism.
False: The golgi apparatus receives transport vesicles at its cis face from the ER.
T or F: The golgi apparatus receives transport vesicles at its trans face from the ER.
False: The lagging strand of DNA is synthesized 5' to 3'.
T or F: The lagging strand of DNA is synthesized 3' to 5'.
False: The max rate that an enzyme is able to convert its substrate occurs when the substrate concentration is very low.
T or F: The max rate that an enzyme is able to convert its substrate occurs when the substrate concentration is very low.
False: The mother's sample depicts someone who is homozygous for the Sickle Cell gene.
T or F: The mother's sample depicts someone that is heterozygous for the Sickle Cell gene (i.e., is considered a carrier).
True
T or F: The pentose phosphate pathway is a great source of NADPH that donates electrons to biosynthetic reactions.
True
T or F: The risk of a urinary tract infection is directly related to the length of time that a catheter is in place.
True
T or F: The trp repressor is inactive when tryptophan is in low levels in the microbe's environment.
False: This organism is a cocci in a predominately staphylo-arrangement.
T or F: This organism is a cocci in a predominately strepto-arrangement.
False: Scientists do not change out the media to construct this growth curve.
T or F: To construct this growth curve, scientists change out the media every 12 hours.
True
T or F: To construct this growth curve, scientists change out the media every 12 hours.
False: Secretion is when proteins are moved from the cytoplasm to the external environment of the cell.
T or F: Translocation is when proteins are moved from the cytoplasm to the external environment of the cell.
spontaneous generation
The concept that living organisms arise from nonliving material is called ________.
retains the cytoplasm and its contents acts as a selectively permeable barrier, allowing some molecules to pass while preventing the movement of others is the major site of ATP synthesis in aerobic bacteria
The cytoplasmic membrane of bacteria ________.
Energy can neither be created nor destroyed
The first law of thermodynamics states that:
group translocation
The image below depicts the first step of glycolysis.
2
The net gain of ATP per molecule of glucose metabolized anaerobically via the Embden-Meyerhof pathway in prokaryotes is ________.
Anticodon
The portion of the tRNA molecule that binds to the codon on the mRNA is called the _____.
acetyl-CoA
The pyruvate dehydrogenase complex (aka the transition step) oxidizes and cleaves pyruvate to form one CO2 and ________.
Both Gram-positive and Gram-negative bacteria
The sec system is used by
is due to a point mutation is the result of a spontaneous mutation changes one amino acid in the hemoglobin protein
The sickle cell gene...
Active site
The substrate of an enzyme binds at the _________.
Bacteriphage therapy is the use of virus that specifiaclly target bacteria to treat bacterial infections. Two advantages of bacteriophage therapy is that there is no known resistance to it and that it does not target our cells. One disadvantage of bacteriophage therapy is that the virus that attacks that bacteria will kill the bacteria cell and lyse it; resulting it free-genetic material that could harm our cells.
The use of bacteriophage may someday replace the use of antibiotics. What is bacteriophage therapy? Also, please describe two advantages, and one disadvantage of bacteriophage therapy.
peptidoglycan
This image above depicts:
G
Use the table and the M-H plate to determine which antibiotic should be prescribed to treat the bacteria grown on the plate.
LPS is found only in Gram positive cells, and is embedded in the cytoplasmic membrane
Which of the following statements is false in regard to lipopolysaccharide?
Koch's postulates attempt to correlate a pathogenic organism with the presence of disease. There are many loopholes to Koch's postulates. For example, asymptomatic carriers exist, so it's not always possible that disease will be present in an infected organism. Additionally, an organism may not be able to be isolated or grown in a lab, therefore, it may not be possible to achieve a pure culture of the pathogen.
What are Koch's postulates trying to prove? What is a caveat (exception) to one of Koch's postulates?
ParB would be unable to bind the region on the chromosome and would therefore not be able to drag the newly replicated chromosome to the other end of the pole septation would most likely chop part of one of the chromosomes, resulting in one daughter cell getting an incomplete copy of the chromosome
What consequence would Escherichia coli face if there was a mutation in its ParS gene?
The presence of an electron transport chain
What distinguishing feature characterizes aerobic and anaerobic respiration but does not play a role in fermentation pathways?
The effect of some mutations would increase
What do you think would be the most likely outcome if the genetic code was not degenerate?
The main complication is build up of crystallized biofilms in the catheters can become blocked. This results in the patient not being able to secret their urine resulting in it being pushed back up into the bladder and beyond. This can eventually cause the patient to become septic and septicia can be lethal.
What is the main complication caused by crystallized biofilms in urinary catheters and why is this so detrimental to a patient's health?
exposure to UV an induced mutation
What is the most likely cause of this type of DNA damage? (check all that apply)
To signal to the ribosome where the protein needs to be taken following translation
What is the purpose of the signal peptide of proteins?
Bacteria can only bring in dissolved compounds, and Fe3+ is extremely insoluble Siderophores scavenge iron from the bacteria's environment
What is the reason that bacteria necessitate the use of siderophores?
horizontal gene transfer
What is the term used to describe the activity occurring in all three images above?
group translocation Because the mannitol is being modified simultaneously as it's brought into the cell (it is phosphorylated in this case) this is a perfect example of group translocation.
What type of transport is occurring in this image?
60 min/hr X 18 hrs = 1,080 minutes 1,080 minutes X 1 generation/38 minutes = 28.42 generations 228.42 = 3.59147 X 108
What would the population of Staphylococcus epidermidis be after an 18 hour incubation at 37C, assuming that S. epidermidis has a generation time of 38 minutes, originating from just one cell?
Plasma membrane
Where is the electron transport chain located in bacterial cells?
C
Which area in the image represents lipoteichoic acid?
Complex
Which capsid morphology is displayed by the virus below?
lophotrichous
Which flagellar arrangement is depicted by the cell in this image?
A, if molecules are dependent on a carrier and that carrier becomes saturated, a transport plateau may occur.
Which line, A or B, represents carrier facilitated diffusion, and why?
actin microfilaments
Which of the following cytoskeletal components is involved in ameboid movement (i.e., the formation of psuedopodia) and is twisted in a helical fashion?
an uncoating step must occur before the pit fuses with an early endosome a type of receptor mediated endocytosis that occurs in eukaryotes
Which of the following describes clathrin-dependent endocytosis?
oxidation of ammonia to yield nitrate
Which of the following describes nitrification?
N2 Due to the strong triple bond shared between the two nitrogens in N2 gas, this compound is considered biologically unavailable to most organisms, except for the microorganisms who are able to convert it into a useable format such as ammonia (NH3).
Which of the following forms of nitrogen is considered biologically unavailable/inert?
capsule
Which of the following helps a bacterium escape phagocytosis by host cells?
Envelope
Which of the following is an "optional" feature of a virion?
biofilm formation occurs in harsh settings, such as extreme heat
Which of the following is false regarding biofilms?
NADH
Which of the following is produced in largest numbers by the TCA cycle?
Yeast are a type of fungi Yeast are capable of reproducing sexually Yeast cells are larger than cells of Escherichia coli, a Gram-negative bacterium Yeast have sterols in their cellular membrane
Which of the following is/are true about yeast?
H2 (hydrogen gas) ammonium (NH4+) S2O3 (thiosulfate)
Which of the following may be used as sources of electrons by chemolithotrophs?
Disk diffusion method
Which of the following methods of determining the MIC did you use to choose the correct treatment in the previous question?
The tryptophan operon is turned off by the presence of the corepressor, tryptophan The AraC protein can act as both a positive and negative regulator of transcription
Which of the following statements is correct?
A The first time an organism is mentioned in a passage, it must be spelled out entirely. This limits us to option A, C, and D. However, according to the rules of nomenclature, the first letter of the specific epithet must be lowercase. Therefore, A is the correct option.
Which of the following would be the correct way to refer to an organism the first time it is mentioned in a passage? A) Pseudomonas aeruginosa B) P. aeruginosa C) Pseudomonas Aeruginosa D) Pseudomonas Aeruginosa E) P. aeruginosa
A
Which of the three images above depicts transformation?
A
Which of the three images above requires that the recipient cell be competent?
C
Which of the three images uses a Type IV secretion system?
Prolonged exposure to a mutagen multiple lesions in the DNA, causing DNA synthesis to come to a halt Prolonged exposure to a mutagen and environmental stressors are ways the SOS response can be initiated. This response is only initiated when the bacteria's genome is so damaged that it cannot use regular repair mechanisms.
Which of these scenarios would elicit an SOS response?
factor dependent transcription termination
Which process is described below? Rho binds to mRNA at a site called rut (rho-utilization-site) and moves along mRNA as it follows RNA polymerase Rho moves more slowly than RNA pol, so the only way it will catch up to RNA pol is if the pol pauses at a rho-dependent pause site When this occurs, rho causes RNA polymerase to dissociate from DNA using its hybrid RNA:DNA helicase activity
They are heavily regulated and are often shut off when not needed They are usually turned off but can be turned on when needed
Which statement is false about housekeeping genes?
The lac operon is an inducible operon, therefore the repressor is bound to the operator, blocking transcription of genes that encode for lactose breakdown when lactose is absent. When the repressor falls away from the operator, RNA pol is free to transcribe. This is due to lactose acting as an inducer.
Which statements are true about how the lac operon of E. coli is regulated? (select all that apply)
The tail fibers
Which structure determines host range of a bacteriophage?
a eukaryotic flagellum
Which structure is described as "composed of 9 pairs of microtubule doublets that surround two central tubules"?
Viruses and prions are acellular entities-- that is, they are not cells, whereas fungi, protists, bacteria, and archaea are all unicellular or multicellular organisms. They require a host cell to be able to replicate and divide.
Why are viruses and prions characterized differently than fungi, protists, bacteria, and archaea?
First of all, you should only take antibiotics that are prescribed to you, so purchasing them in Mexico is a big no-no. Secondly, antibiotics will not do anything to stop a cold-- antibiotics fight bacteria, not viruses. Third, she stops taking them after feeling better. If she did have a bacterial infection and didn't finish her antibiotics, this would be selecting for resistant bacteria. Finally, antibiotics do not cause resistance. They select for resistant organisms.
Your best friend Rhaenyra feels a cold coming on and immediately reaches for the Penicillin she bought while on vacation in Mexico. After a few days, she feels better, so she stops taking them. Not only this, but you overhear her telling another friend, "I stopped taking my antibiotics because I know they just cause resistance anyway." There are several flaws with your friend's logic in this scenario. Please describe all of them that are mentioned, and why they are flaws.
Entropy
________ is a measure of the randomness or disorder of a system.
transfer RNA
______________ molecules deliver amino acids to ribosomes during translation
fluoroquinolones
contains a fluorine molecule, and binds to DNA gyrases and topoisomerases
penicillin
contains a structure that is an analog to the D-ala of peptidoglycan
polymyxins
damage cell membranes
Both the hydrogenosome and the mitochondria are organelles involved in energy production for the cell. Whereas the mitochondria is involved in aerobic respiration where O2 is used as a final electron acceptor, the hydrogenosome is used in anaerobic protists that don't use O2 as a final electron acceptor. Whereas the mitochondria produce a ton of ATP for the cell, the hydrogenosome does not produce as much.
hydrogenosome vs. mitochondria
vancomycin
large molecule that binds to the D-ala of peptidoglycan
Both result in the generation of ATP. Substrate level phosphorylation occurs in glycolysis and TCA cycle, whereas oxidative occurs in ETC. Whereas substrate level phosphorylation is the process used in fermentation to make ATP, the ETC is the primary source of ATP in aerobically respiring organisms.
substrate level phosphorylation vs. oxidative phosphorylation
aminoglycosides
target the 30S rRNA, resulting in disruption of protein elongation
Polyenes
targets the cytoplasmic membrane of fungal pathogens
rifamycin
targets the process of transcription
When tryptophan binds to the repressor
the repressor is activated and is able to bind to the operator sequence, turning transcription off..
When lactose binds to the repressor
the repressor is inactivated and falls off of the operator sequence, turning transcription on.
isoniazid
would most likely be used to treat tuberculosis infection