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40 Cards in this Set
- Front
- Back
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What bacteria is the common cause of ear infections? |
Streptococcus pnuemoniae |
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According to Frederick Griffin, what were the 2 types of bacterial colonies found in people? |
Rough Pretty <- would cause mouse to be infected and die |
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What's the difference between rough and pretty/smooth bacteria? |
Rough = No capsule (Capsule -) = No death Pretty = Capsulated (Capsule +) via polysaccharide coat outside peptidoglycan cell wall= Deadly |
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What was the significance of Avery, MaCloud, and McCrary redoing Griffin's experiment? |
They figured out DNA is the transforming piece. |
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What were the two radioactive labels in Hershey and Chase's experiment? |
P-32 for DNA, S-35 for proteins |
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What is lyme disease caused by? |
Bacteria with 20 linear strands |
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What's the purpose of Dna A, Dna B, and Dna C in replication? |
Dna A recognizes and binds OriC (along with binding proteins), and then promotes replication by recruiting Dna B Dna B unwinds DNA and requires ATP Dna C loads/localizes Dna B -> Dna A+OriC |
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What are some quick facts about DNA pol III? |
•Catalyzes DNA synth @ 1000 nts/sec •Takes 40 min to replicate E. Coli genome •Multiple replication forks => faster replication •Error rate: 1/1 billion to 1/10 billion |
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What are the most important things about DNA pol I? |
Most abundant polymerase (400/cell), used to remove RNA primers |
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Why is priming important? |
DNA polymerase can't initiate DNA synthesis from a naked DNA strand; a double stranded nucleic acid is required. |
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What does RNA primase do? |
Along with Dna G, synthesizes RNA primers |
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What is the half-life of mRNA in bacteria compared to humans? |
Half-life! Bacteria: 2.5-3 min, humans: 10-12 hrs This is because bacteria evolved to turnover mRNAs quickly so they can respond to change fast. |
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How is mRNA polycistronic? |
It contains multiple genes called operons which are transcribed on one transcript |
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What is the 30s subunit composed of? |
16s rRNA and ~21 ribosomal prots |
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What is the 50s subunit composed of? |
23S rRNA, 5S rRNA, ~34 ribosomal prots |
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What is the sequence Shine-Dalgarbo sequence Gram + and Gram - bacteria require? |
Gram +: AGGAGGU (very consensus) Gram -: AGG (more lax) |
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What are the 3 ways proteins get processed after being translated? |
1. Folding into their proper 3D structures by chaperones 2. Covalent modifications (phosphates, glycosylation) 3. Translocation- putting proteins in the right place |
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How is the needle-structure from Type III Secretion used as evidence in the argument of Evolution vs. Creationism? |
It looks to have evolved from flagellum as it looks almost exactly the same, but has an entirely different function. |
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Explain how fluorescence is achieved. |
You excite a photon with a particular wavelength, which causes it to emit a higher wavelength. |
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What is a protein fusion? |
When GFP or other fluorescent proteins covalently link to the amino acid sequence of a protein. |
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What does MreB do? |
Helps give bacteria their rod shape by forming rings throughout the cell; forms cell cyroskeleton. Without it, it would be cocci in shape. Localizes synthesis of new peptidoglycan & other cell wall components to specific locations along rod shape during growth. It was originally thought helical structures gave the rod-shape but this protein proved that wrong. Structure aids with: surface area and motility |
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What bacteria is the exception to binary fission and what does it do instead? |
Epulopiscium fishelsoni- Gives birth to live young; daughter cells develop inside and then the original cell lyses to release. |
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What are essential targets for antibiotics? |
Peptidoglycan and cell wall, protein synthesis (30S + 50S subunit), DNA/RNA synthesis, and antimetabolites in the cytoplasm |
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What are important characteristics antibiotics should have? |
Must be small (MW <600) to be able to get to Gram - Hydrophilic so can be soluble in blood Targets bacterial cells only Others: Minimal side effects Low toxicity but may be allergeni Naturally occurring |
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What is synergism? |
A combination of 2 antibiotics with enhanced overall bactericidal properties compared to each compound alone. Ex) Ampicillin (beta-lactamose target) + Clavulonic acid (beta-lactamose inhibitor) => augmenten Doing this broadens antibacterial spectrum and decreases chance of resistance developing |
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What are ways to restrict antibiotic access? |
•Gram (-): Change in outer membrane porins •Gram (+): Change number of techoic acids •Decrease uptake across cytoplasmic membrane by changing receptors •Change charge of outer membrane so antibiotics can't bind (charged antibiotics help bind to outer membrane) •Drug efflux pumps to pump antibiotic out; multi-drug pumps many drugs out, 1 drug induces them to be made so now resistant to many drugs |
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How do bacteria develop resistance? |
Mutation (very rare, but helps), may get from elsewhere through cloning (easier) |
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How has triclosan changed? |
It used to be highly effective in anti-microbial properties, but not anymore because bacteria are essentially resistant to it due to overuse. |
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What does it take to be a good antibiotic? |
Few or no side effects (differential toxicity), broad spectrum |
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What are the problems of using a good antibiotic? |
Broad-spectrum may attack both dangerous and harmless bacteria, which may contribute to resistance. |
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What are replicons? |
DNA molec capable of autonomous replication (chromosome and viable plasmids). All have an ori. |
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What are the two ways plasmids are replicated? |
1. Theta Replication 2. Rolling circle |
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How are plasmids able to exist within the same cell? |
If there are multiple ori sites. |
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Plasmid compatibility |
Ability of 2 different plasmids to coexist in the same host- plasmids using same replication system can't co-exist in the same bacterial cell (if do, belong in same incompatibility group) |
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Plasmid partitioning |
P=2x(1/2)^2n |
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If you want to isolate a highly antibiotic resistant strain of bacteria from a patient, how would you find the resistant gene? |
•Sequence genome and compare to non-resistant strain •Isolate gene of interest and use PCR to amplify gene •Plasmid extraction: clone to plasmid using multi-cloning site •DNA digestion with non-resistant DNA and restriction enzymes •Blu/white screening to see if becomes resistant (lawn forms) •Analysis |
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What is required in PCR? What are the steps? |
DNA, DNA pol, dNTPs, buffering conditions, primers 1. Melt DNA to separate 2. Cool strands slightly for primer to bind 3. Heat for DNA pol to start synthesizing 4. Repeat 30 times |
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How does one accomplish plasmid extraction? |
(Alkali lysis method) •Use high salt and pH concentration of DNA which denatures and precipitates chromosomal DNA. Plasmid DNA is soluble and renatures easily, purifies on chromatographic column. •Select RE site and appropriate PCR primer for site. |
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Blu/white screening |
White contains foreign DNA and is recombined, blue doesnt |
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Gel Electrophoresis |
From - (cathode) to + (anode). Further distance = smaller size |
