VBS 2032 Exam 1
How can bacteria use carbon/energy sources other than glucose as starting molecules?
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What are some examples of ways that viruses can be engineered to treat or prevent disease?
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What is the human "phageome"? How is this distinct from the virome? What are some ways phages can either promote health or disease?
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What are some surprising places microbes are found?
- Ocean, self, animals, food, social vegetables, babies have their own biomes, hot springs, glacier (never see oxygen, survive on iron and saline, high metabolism), areas with or without air - Basically anywhere on Earth
Compare and contrast the different types of heat treatments. Which one(s) result in sterilization?
1. Boiling: 5 mins destroys most microorganisms/viruses; doesn't destroy endospores 2. Pressurized steam/autoclaving: 121 degrees C/15psi for 15+ minutes, destroys endospores, RESULTS IN STERILIZATION!!! 3. Incineration: burns components to ashes 4. Dry heat ovens: destroys cell components and denatures proteins, less efficient than moist heat; takes a long time and v high temps 5. Filtration of fluids: used for beer/wine, sterilizes some heat-sensitive medsused to remove bacteria 0.2 um 6. Filtration of air: used to remove bacteria 0.3 um or greater 7. Ionizing radiation: destroys DNA and damages cytoplasmic membranes; sterilize heat-sensitive materials like med equipment, disposable surgical supplies 8. UV radiation: damages DNA, penetrates poorly; used to destroy microbes in the air and drinking water, disinfects surfaces
What is an example of a human disease caused by reactivation of a latent virus?
1. Botulism (Clostridium botulinum) 2. Scarlet fever (streptococcus pyogenes) 3. Hemolytic uremic syndrome (E. coli)
Make your own version of table 3.3 in the book. What are the structures of the prokaryotic cell? What are the characteristics and functions of each? 3 CELL WALL
1. Cell Wall: Peptidoglycan proves rigidity to bacterial cell walls, preventing the cells from lysing 2. Gram-positive Thick layer of peptidoglycan that contains teichoic acids and lipoteichoic acids 3. Gram-negative Thin layer of peptidoglycan surrounded by an outer membrane. The outer layer of the outer membrane is lipopolysaccharide
Make your own version of table 3.3 in the book. What are the structures of the prokaryotic cell? What are the characteristics and functions of each? 8 INTERNAL COMPONENTS
1. DNA: Carries the genetic information of the cell 2. Chromosome: Carries the genetic information required by a cell. Typically, a single, circular, double-stranded DNA molecule 3. Plasmid: Generally carries only genetic information that may be advantageous to a cell in certain situations 4. Endospore: A type of dormant cell that is extraordinary resistant to heat, desiccation, ultraviolet light, and toxic chemicals 5. Cytoskeleton Protein framework involved in cell division and control of cell shape 6. Gas vesicles Small, rigid structures that provide buoyancy to a cell 7. Granules: Accumulations of high-molecular-weight polymers, synthesized from a nutrient available in relative excess 8. Ribosomes: Involved in protein synthesis. Two subunits, 30S and 50S, join to form 70S
Make your own version of table 3.3 in the book. What are the structures of the prokaryotic cell? What are the characteristics and functions of each? 6 STRUCTURES OUTSIDE THE CELL
1. Filamentous appendages: Composed of protein subunits that form a helical chain 2. Flagella: Provide the most common mechanism of motility 3. Pili: Different types of pili have different functions. The common types often call fimbriae, allow cells to adhere to surfaces. A few types are used for twitching or gliding motility. Sex pili are involved in DNA transfer 4. Capsules and slime layers: Layers outside the cell wall, usually made of polysaccharide 5. Capsule: Distinct and gelatinous. Allows bacteria to adhere to specific surfaces; allows some organisms to avoid the body's defense systems and thus cause disease 6. Slime layer: Diffuse and irregular. Allows bacteria to adhere to specific surfaces
What parts of the cell can act as virulence factors?
1. Flagella virulence factors: can increase its motility and ability to stick to host cells 2. Pili (fimbriae) virulence facters: help to hold onto and twitch through mucus 3. Having a cell wall increase virulence because it can be harder to get to the inside of the virus 4. Glycocalyx is a virulence factor because slime layers and capsules help attachment, protection from desiccation, and host invasion
What are the basic differences between Gram-positive and Gram-negative bacteria? What is a porin? What is the medical significance of LPS?
1. Gram positive: single cytoplasmic membrane and a thick peptidoglycan layer (give cells rigid structure with carbohydrate crosslinks). More susceptible to antibiotics 2. Gram negative: thin peptidoglycan and second selective outer membrane (bilayers, phospholipids on the outside, porins, lipopolysaccharide). Antibiotics, or gram stain, cannot get through outer membrane. Especially the porin, which are proteins in the outer membrane of gram-negative bacteria that form channels through which small molecules can pass. Bacteria can adjust size of porin and make the channel smaller so antibiotics cannot get in. Medical Significance of LPS: 1. Lipopolysaccharide (LPS): Molecule that makes up the outer layer of the outer membrane of gram-negative bacteria 2. Medical significant because antibiotics cannot get through the outer membrane in the gram-negative membrane:
What two scientists helped explain the conflicting data?
1. John Tyndall (1876): discovered some microbes have a heat resistant form. Some can be boiled and killed, some can be boiled and stay alive. Used a hay broth that has microbes that are heat resistant whereas a yeast extract and sugar broth do not have heat resistant microbes 2. Ferdinand Cohn Cohn (1876): discovered heat resistant microbes are a type of gram-positive bacterium that produces endospores
Pasteurization
1. Kills most microbes but leaves some 2. Makes it safe to drink without ruining the flavor
What are two ways microbes have changed that impact healthcare?
1. Microbes can be pathogenic (Cause diseases) 2. Microbes can be resistant to hospital treatment (Antibiotic resistant)
What are three ways in which microbial activity is essential for life on this planet?
1. Nitrogen fixation: Process in plants which nitrogen is reduced to form ammonia, which can then be incorporated into cellular material. Take unusable nitrogen and make it usable. 2. Recycling: break down all the leaves so that other plants can reuse their nutrients 3. Oxygen production: photosynthetic algae produce majority of our oxygen
Oxygen requirements of microorganisms:
1. Obligate aerobe: grows only when oxygen is available. Requires oxygen for respiration 2. Facultative anaerobe: grows best when oxygen is available, but also grows without it. Uses oxygen for respiration if available 3. Obligate anaerobe: cannot grow when oxygen is present. Does not use oxygen for respiration. 4. Microaerophile: grows only if small amounts of oxygen are available. Requires oxygen for respiration 5. Aerotolerant anaerobe grows equally well with or without oxygen. Does not use oxygen.
Advantages of a waxy coating for Mycobacterium tuberculosis?
1. Prevent against desiccation or drying out 2. Can live longer in their environment 3. Harder to kill, requires stronger disinfectant got get rid of them 4. Can enter a host without detection and replication really slowly and protect themselves
What are some basic differences between prokaryotic and eukaryotic cells?
1. Prokaryotic: lack membrane bound organelles and have nucleoids and circular DNA, usually smaller. Example: bacteria 2. Eukaryotic: contain membrane bound organelles, including a nucleus and linear DNA. Examples: Single celled or multicellular humans, plants, fungi, insects
What environmental factors influence enzyme activity?
1. Temperature 2. pH 3. Salt 4. Substrate levels 5. Product levels 5. Inhibitor levels
What two scientists are credited with discovering microorganisms?
1.Antonie van Leeuwenhoek: Created the microscope 2. Robert Hooke: Published Micrographia in 1665, a book with very detailed drawings of microorganisms
What is the "indoor microbiome?"
A diverse group of microorganisms that reside in our homes. Building design choices (flooring material) and behavioral choices (cleaning frequency) can influence our daily exposure to different species
What is the difference between a virus and a phage?
A phage (bacteriophage) is a type of virus that attacks bacteria whereas a virus attacks human, or host, cells
What is the energy currency of the cell? What general set of reactions produce it? What type of reactions use it?
ATP Energy is made through catabolic reactions (endergonic reactions) Energy is used in anabolic reactions (exergonic reactions)
How did scientists make the link between bacterial metabolism and TMAO accumulation?
According to research, TMAO levels are high when people have heart disease Does carnitine, which comes from meat, go to TMAO? Research studies found that mice who were given carnitine, have high levels of TMAO Another experiment found that when vegans ate steak and meat eaters ate steak, only the meat eaters had TMAO in their blood. So where does TMAO come from? Was it the bacteria in the gut that made the TMAO? To find out they had two meat eater groups and one set was given antibiotics and the other was not. They ate steak in the morning. The group that got antibiotics did not have TMAO
What is the difference between an acidophile and a neutrophile? Which one would grow in a jar of pickles?
Acidophile: grows optimally at a pH below 5.5 Neutrophile: multiples in range of pH 5 to 8 Alkalophile: grows optimally at a pH above 8.5 Most microbes are neutrophils (pH 5-8). Pickles: Vinegars are in the jar (acidic). Salt in jar. No oxygen. Acidophile would grow
What is the difference between an acute, chronic and latent viral infection? Which one is most likely to spread when the host is asymptomatic?
Acute: you have infectious virus particles before, during and after and then it's gone (doesn't last that long) Chronic: you have infectious virus particles before, during, and forever even when you are not sick Latent: you get the infection again and again. It can come back whenever (spread when asymptomatic, meaning you do not show symptoms)
Can cellular respiration be anaerobic? What type of molecule would be the final electron acceptor?
Anaerobic respiration: alternative electron acceptor (NO3) Electron transport chain -> PMF -> ATP
Why are enzymes necessary?
Any bonds being broken or made require enzymes in their process to lower to amount of activation energy needed. Break bonds easier
How do viruses attach to cells?
Attach to cell via spikes. Lipid membrane fuses with cell membrane. Entire cell is injected, the protein capsid and nucleic acid enter the cell. Capsid is removed and the nucleic acid is released
How are microorganisms named?
Binomial nomenclature developed by Carl Linnaeus in the 1700's. Genus (italicized with first letter capitalized) species
Pasteur's swan-necked flask experiment
Boiled broth, let the air out, when the broth cooled, air came back into the flask but the broth did not spoil because the molecules of air have microbes in them. The microbes have weight and could not get all the way through the neck of the flask so settled in the bend of the flask rather than entering. Once flask was tipped, broth contacted the microbes and was no longer sterile. Used yeast extract and sugar broth
What are the basic components of a cell membrane? What are some functions that membrane proteins serve?
Cell Membrane: Composed of phospholipids (Hydrophilic head, loves water, Hydrophobic tails, hate water). Function: provide a selectively permeable membrane, decides what can and cannot come in. i. Proteins are embedded: 1. Selected permeable 2. Transport a. Active (requires ATP) b. Passive (does not require energy) 3. Help cells communicate 4. Help with attachment 5. Involved in movement 6. Can be enzymes, meaning they are involved in metabolism
What is the function of each of the pathways below? What is the input and yield of each? CELLULAR RESPIRATION
Cellular respiration: Aerobic NADH and FADH2 gives it electron to NAD dehydrogenase, then to various other things until it gets to Os where water is produced. Energy is produced by the proton motive force. The electron is passed from the inside of the cell to the outside creating a low pH on the outside which the ATP synthase uses as a driving force
What are some ways that the Chain of Infection can be broken?
Chain of infection: virus travels from sick person to vulnerable person Can be broken: 1. Isolate and treat patient 2. Wash hands 3. Disinfect surfaces 4. Vaccinate
What is the function of cholesterol in some eukaryotic membranes? How do bacteria maintain their shape? Mycoplasma?
Cholesterol stabilizes some eukaryotic membranes and gives structure because the molecule is rigid. Membranes contain sterols, which provide strength to the otherwise fluid structure Prokaryotes do not have cholesterol, so they use peptidoglycan to maintain their shape. Mycoplasma take cholesterol from you, the human body or host, because they do not have it and stick it in their membrane to stabilize themselves. They are fastidious, have nutritional requirements they cannot make for themselves.
What is "C. diff"? Why is it difficult to control in a hospital setting?
Clostridium difficile ( C. diff) is difficult to control because it can occur from taking too many antibiotics and clearing all of the intestinal microbes in your gut. Also produces endospores: resistant to heat, UV rays, desiccation, and toxic chemicals. Threat to healthcare facilities because they are hard to kill and easy to spread
What is a way in which microbes can compete in a biofilm?
Communicate via chemical signals. Do separate jobs to coexist by doing specific things
What is a ribosome composed of? What is the function of a ribosome?
Composed of proteins and rRNA. rRNA takes up more space of a ribosome. Complex with a large subunit which joins amino acids to form a polypeptide chain and a small subunit which reads RNA. Located in the cytoplasm and involved in protein synthesis
From MMWR: How could the potato salad have been prepared safely? (Why did people become ill?).
Cook the potatoes in a pressure cooker so that there would be hot steam to get into the crevasses of potatoes and kill all the endospores before canning, or use store bought fresh potatoes
How are pickles made? What factors promote the growth of lactic acid bacteria? What inhibits the growth of spoilage bacteria? Where do the "good" lactic acid bacteria come from?
Cucumbers + Salt + Water. Screw on the lid, but not too tight because you need a way for gas to escape. No oxygen because lactic acid bacteria doesn't need oxygen. temp just right. In less than a week, acid is produced (lactic acid). Neutrophilic microbes cannot grow. Cucumbers have microbes and bad microbes are taken away by salt.
Be able to define and compare/contrast the following terms: (antiseptic, disinfectant, sterilant),(sterilization, Pasteurization, disinfection),(bacteriostatic, bactericidal), Preservation.
Disinfectant: a chemical that destroys many but not all microbes Sterilant: free of all viable microbes (except sometimes prions) Sterilization: destruction or removal of all microbes (physical or chemical) Pasteurization: brief heat treatment that reduces number of spoilage organisms and destroys disease-causing microbes Bacteriostatic: prevents growth of bacteria, doesn't kill Bactericide: substance that kills bacteria Preservation: inhibition of microbial growth to delay spoilage
According to the Endosymbiotic Theory, what is the origin of mitochondria? Of chloroplasts? (What takes place in the chloroplast?)
Endosymbiotic theory states that at some point a cell engulfed a bacterium and that bacteria stayed there and eventually become a mitochondrion. Double membrane and DNA sequence of their chromosomes similar to Rickettsia. The same thing is assumed to have occurred with chloroplasts. The DNA sequence of chromosomes and double membrane in a chloroplast is similar to cyanobacteria
We do not yet know the extent of microbial diversity. Why not?
Extent of microbial diversity is unknown because many have not yet been discovered. Not all microbes are able to be cultured because we cannot recreate optimal growing environments in the lab
What is EPS and what does it do?
Extracellular polymeric substance: Gooey substance or polysaccharide or DNA its protective for biofilms and cells can be cooperating or competing.
What is the electron acceptor in fermentation? What are some byproducts?
Fermentation: metabolic process that stops short of oxidizing glucose or other organic compounds completely using an organize intermediate as a terminal electron acceptor. Cells break down glucose through glycolysis only, thereby generating pyruvate. The cells then use the pyruvate or a derivative of it as a terminal electron acceptor. By transferring the electrons carried by NADH to pyruvate or a derivate, NAD+ is regenerated In the absence of O2, some cells use pyruvate as a terminal electron acceptor Input: pyruvate Byproducts: lactic acid, ethanol, butyric acid, propionic acid, mixed acids, 2,3 butanediol
How could you sterilize an antimicrobial drug solution for injection?
Filtration of fluids!
Your friend recently ate a salad containing a brand of spinach that was recalled for contamination with E. coli. Can you explain to her the factors that will influence whether or not she becomes ill?
Formula: [(number of microbe) (virulence of microbe)] / host immunity
Why don't most people get fungal lung infections?
Fungi rarely cause infection because they CANNOT PENETRATE OUR SKIN and would not thrive in the human body but can occur as athletes foot or skin trauma. We have cilia and immune cells in lungs so we usually fight them off but.... Hypersensitivity reaction: allergy or asthma
What does the term "generation time" mean? How can the total number of cells in a population be calculated if the generation time is known? (What is the formula and can you use it?)
Generation time = time it takes for the bacterial population to double N0 * 2n -> Nt N0: number of cells at time 0 (beginning) 2n: number of generations (the number of doublings) Nt: number of cells at the end
What is the function of each of the pathways below? What is the input and yield of each? GLYCOLYSIS
Glycolysis: takes glucose into 6 carbons and removing the electrons Input: 2 reducing molecules (NADH) and 2 ATP and 6 precursors Yield: Pyruvate comes out
Which group of bacteria is likely to be most resistant to disinfectants and antibiotics? Why?
Gram negative is more resistant to disinfectants and antibiotics because they have an outer membrane layer with LPS in that antibiotics cannot get through. Especially the porin, bacteria can adjust size of porin and make the channel smaller so antibiotics cannot get in. To get infected with Gram negative is very dangerous, Blood pressure drops, organ failure (50% of dying)
What properties of bacterial cell walls allow for discrimination by the Gram stain? The Acid-fast stain? What group of bacteria is considered "acid-fast"?
Gram stain: Peptidoglycan in the cell wall is what the dye sticks to and makes the difference between the two bacteria. Gram-positive turns purple and Gram-negative turns pink. Acid-Fast: Mycobacteria (group of organisms that includes tuberculosis, Mycobacterium tuberculosis) have a waxy coating that prevents entry of the gram stain but they are gram-positive
(From the 1st microbial metabolism lecture) What does the term "fastidious" mean in microbiology?
Have nutritional requirements they cannot make for themselves
Where might copper be used in a hospital setting?
Heavy metals have antimicrobial properties. Can be embedded into bed rails or door handles (very often touched surface). Reduces amount of microbes transmitted
What is the "Hygiene Hypothesis" and how might dogs (and other animals) positively impact our health?
Hygiene Hypothesis: Suggests that when we look at developed countries, like the USA and Europe, we see a higher abundance of allergies and asthma than in the undeveloped world. Suggests that we are living in environments that are too clean. By not being exposed to microbes our immune system is not trained properly so we overreact to things and we develop conditions like asthma. Answer: Dogs and animals can expose humans to more microbes and they create a more of an "unclean" environments. Getting different species of bacteria and fungi
Why are there relatively few antiviral drugs (as opposed to antibacterial drugs)?
In order to kill a virus, it would need to inhibit host cell ribosomal synthesis. They mutate too fast
Where does the substrate bind on an enzyme? How does the enzyme catalyze the chemical reaction?
Induced fit model: A substrate binds to an active site and both change shape slightly, creating an ideal fit for catalysis. When an enzyme binds its substrate, it forms an enzyme-substrate complex
How could you sterilize a hospital mattress?
Ionizing radiation
Why would an infection involving a biofilm be difficult to treat? Why might the microorganisms be difficult to identify?
It is hard to get rid of the biofilm so the bacteria are even harder to kill. Some of the species cannot be cultured and if they are in the biofilm and cannot be culture, then we don't know how to get rid of them
What kinds of bacteria lack cell walls? What is an example of an obligate intracellular bacterium? (What does obligate intracellular mean?
Lack cell walls: 1. Mycoplasma: lack cells walls entirely (no peptidoglycan). Not much of a shape 2. Protozoa Obligate intracellular bacteria: 1. Rickettsia sp. Can find by looking inside of the host cell because it can only live inside of the host cell, cannot produce outside of their host cell
What fermentation byproduct can accumulate in muscles during intense anaerobic exercise?
Lactic Acid or Lactate??
What are the relative sizes of a human cell, a protein, a virus and most bacteria?
Largest to smallest: humans, most eukaryotic cells, most bacteria, viruses, proteins
When a bacterium is in a state of lysogenic conversion, why does it express a different protein(s)---often a toxin? What does this mean for the pathogenicity of the bacterium?
Lysogenic conversion is when a phage is in a latent state (where no viral particles are made, but DNA is in each replication of the host cell). Bacterial populations can become more or less pathogenic, and the viruses are the ones that move the genes around A temperate phage induces a change in the phenotype of the infected bacteria that is not part of a usual phage change
What is the difference between lytic and temperate phages?
Lytic phage: a virus that infects bacteria and kills the cell Temperature phage: restraint or self-controlled, doesn't go wild and kill all the cells all the time
Why are microbes generally more resistant to antibiotics and disinfectants when growing in a biofilm?
Microbes within the biofilm often resist the effects of antibiotics as well as the body's defenses. The conditions within the biofilm protect the microbes, so the bacteria in a biofilm may be hundreds of times more resistant to disinfectants than their planktonic counterparts Stages 1. Planktonic bacteria move to the surface and adhere 2. Bacteria multiply and produce and extracellular polymeric substances (EPS) 3. Other bacteria may attach to the EPS and grow 4. Cells communicate and create channels in the EPS that allow nutrients and waste products to pass 5. Some cells detach and then move to other surfaces to create additional biofilms
Check your book. How is milk typically Pasteurized? How does the fat in ice cream affect the conditions for Pasteurization of ice cream?
Milk is pasteurized by heating it to 72 degrees celsius for 15 seconds. The conditions used to pasteurize ice cream mix are greater than those used for fluid milk because of increased viscosity from the higher fat, solids, and sweetener content, and the addition of egg yolks in custard products. Fat in ice cream makes it necessary to pasteurize it for 20 seconds at 82 degrees celsius
Most microbes are not harmful. What are some reasons for this?
Most have characteristics that are different to ours, some benefit human hosts, some don't have the same virulence factors. Examples: Lack of virulence factors and non-pathogenic, Live on body, We breathe them in, Train immune system, Help with digestion
What is a chemoorganoheterotroph? A photoautotroph?
Most pathogens are chemoorganoheterotroph Chemo: energy source = organic compounds organoheterotroph: carbon source = organic compounds Photoautotroph: energy source = light, carbon source = CO2
According to Paul Stammets, how can fungi help save the world?
Mushrooms could be used to clean up waste like oil and that they could be used as a pesticide and a fuel source
Why was there only one fatality?
Negative immune response and died of respiratory failure as a result of the virus. The others were caught in time due to the rapid response of healthcare professionals
Is a virus considered a microorganism? Why or why not?
No, a virus is an acellular infectious agent because it only has either DNA or RNA. Not a living organism
What is the difference between an enveloped and non-enveloped virus? What is the envelope composed of and where do viruses obtain an envelope?
Non-enveloped consist entirely of nucleic acid (DNA or RNA and protein). Nucleic acid is enclosed by protein which is what we call the capsid Enveloped have a nucleocapsid, matrix protein, and an envelope Both have spikes sticking out which allows viruses to adhere/bind to them
What ATP generating options would an obligate aerobe have? A facultative anaerobe? An obligate fermenter? An obligate anaerobe?
Obligate aerobe: aerobic respiration Facultative anaerobe: most flexibility, prefers aerobic respiration if oxygen is available but can use anaerobic respiration or fermentation (E.coli can use all 3) Obligate anaerobe: have to use anaerobic respiration or fermentation
Why is salt a good preservative?
Osmosis (Water availability): Salt on the outside of the cell drawers water outside of the bacterial cell so the cell is shriveled up on the inside. Stops from growing even if it doesn't kill it. Salt will lyse (bad) cells so they dry out and die
Why did some scientists have difficulty achieving the same result as Pasteur with the swan-necked flask?
Pasteur used yeast and sugar broths while the others used a hay-based broth which had heat resistant microbes
Why does Pasteurized milk eventually spoil in your refrigerator?
Pasteurization aims to achieve a "log reduction" in the number of viable organisms, reducing their number so they are unlikely to cause disease. However, Bacterial spores and remaining germs/bacteria eventually spoil conventionally pasteurized milk, since they can survive pasteurization.
Could penicillin be used to treat a patient with pneumonia caused by Mycoplasma pneumoniae? Why or why not?
Penicillin cannot be used to treat a patient with this type of pneumonia because Mycoplasma do not have cell walls. Penicillin blocks cell wall synthesis which won't help bacteria that do not have cell walls. Could not treat because no cell wall with peptidoglycan and P enicillin targets and attacks the peptidoglycan of cell walls. Penicillin prevents peptidoglycan synthesis and kills actively binding bacteria (mostly gram positive)
In terms of the human microbiome and metabolism, why is eating a fiber-rich diet good for you?
People who eat more plants have more gut diversity Low fiber diet: began to develop gut microbes that were less diverse (losing microbes) Offspring have even fewer microbes, some microbes became extinct and they couldn't regain the microbial diversity High fiber diet: more diversity, better bacteria Bacteria may use a different energy source. Could use mucus, mucus layer goes away→ leaky gut syndrome
What are the phases of the growth curve? What is happening during each phase? How might bacterial growth in pure culture be different than growth in a natural setting?
Phases of growth curve: 1Lag phase: getting ready to grow, transcribing. Extensive macromolecule and ATP synthesis but no increase in cell number. Cells begin synthesizing enzymes required for growth 2. Exponential growth: growing exponentially (optimal growth). Fast growing bacteria with small increment of time they will increase quickly. Slow growing bacteria with small increment of time they will increase slowly. Endospores grow (2 degree metabolites eg. antibiotics). Antibiotics kill only actively dividing cells. Best phase for antibiotics to work 3. Stationary phase: growth rate slowing, cells run out of nutrients, waste is piling up, organisms can grow endospores, and could make something to inhibit growth of others. Cell death and multiplication is equal. Cell division and cell death to balance out and equal a sum of 0. Number of cells dividing = number of cells dying. Run out of nutrients when they reach this space. Run out of space. Start swimming in own waste products 4. Death phase (prolonged decline): start dying, some are persisters (live by hibernating and survive antibiotics because they kill actively living cells). Have persisters: They don't divide, not much metabolism, they just hangout until times get better. Cannot be killed with antibiotics. I mmune system is depressed
Make your own version of table 3.3 in the book. What are the structures of the prokaryotic cell? What are the characteristics and functions of each? 1 Cytoplasmic Membrane
Phospholipid bilayer embedded with proteins. Surrounds the cytoplasm, separating it from the external environment. Also transmits information about the external environment to the inside of the cell
Where are several places microbial biofilms can be found in daily life?
Plague on your teeth, places with running water (Sink), pond - scum on top, slimy slippery rocks, stents, catheter
What are precursor metabolites used for?
Precursor metabolites are converted by energy into subunits such as amino acids, nucleotides, monosaccharides, and fatty acids. They are the building blocks of other things. They can be oxidized to generate ATP
What does the term "ubiquity" mean?
Present everywhere
Is there a cure for prion disease?
Prions: infections protein molecule No cure for these, they lead to death but it's rare, mostly leads to spongiform encephalopathy
What are enzymes most commonly composed of?
Proteins or sometimes RNA
What types of enzymes do microbes need to produce in order to survive in the presence of oxygen?
Reactive oxygen species (ROS): harmful derivatives of O2 such as superoxide and hydrogen peroxide that are highly toxic to cells Examples: 1. Superoxide (O2-) 2. Hydrogen peroxide (H202) Protective enzymes: 1. Catalase 2. Superoxide dismutase
What is reducing power? What are two molecules used as reducing power in metabolic pathways?
Reduced chemicals which serve as electron donors in reduction reactions (source of electrons for reduction of COs during photosynthesis) NADH + H, FADH2, and NADPH + H are reducing agents When something is reduced, an electron is being added to a molecule and the reducing agent is where the electron comes from
How are bacterial and eukaryotic ribosomes different? (What is the function of a ribosome?)
Ribosomes overall work the same way in bacteria and eukaryotes, they synthesize proteins. Bacterial ribosomes are smaller while Eukaryotic ones are larger. They work the same way with slight differences. They also have different sequences of genes, rRNA is used as an evolutionary marker because it changes very slowly. S units for prokaryotes is 30S + 50S S units for eukaryotes is 60S + 40S
What is a virulence factor?
Something that makes a microbe (bacteria, fungi, virus, protozoa) more potent to the host its attempting to infect
What is substrate-level phosphorylation? How is it different from oxidative phosphorylation?
Start with substrate with a phosphate, then the phosphate gets added to ADP to make ATP (one substrate to another)
What is the function of each of the pathways below? What is the input and yield of each? TCA CYCLE
TCA cycle: Acetyl CoA goes in a CO2 and COs goes out along with NADH, FADH2, precursor molecules and 2 ATP Bacteria and all things have the TCA cycle
Watch the endospore animation. How and when are endospores formed? What two bacterial genera produce endospores?
The bacterium divides in the cell wall, and one side engulfs the other, creating a double membrane around the DNA. Before the newly formed endospore is released, it is dehydrated and allowed to mature. This occurs in gram-positive bacteria. Bacillus and clostridium are formed
Can you explain how the swan-necked flask experiment helped disprove the idea of spontaneous generation?
The bend in the neck of the flask prevented falling particles from reaching the broth but still allowed free flow of air. Ended the argument that unheated air or the broths themselves contained a "vital force" necessary for spontaneous generation
Why does the research described in "An Irresistible Newcomer" represent a breakthrough discovery?
The research represents a breakthrough discovery because scientists may have uncovered an antibiotic that targets lipid molecules, making the development of resistance difficult
Why are viruses usually specific for a single cell type and/or single host species?
They are more easily able to attach to them. They sense a certain spot on the membranes and attach better
What is the function of each of the pathways below? What is the input and yield of each? TRANSITION STEP
Transition Step: Pyruvate uses 3-carbons to produce CO2 and 2 carbons and Acetyl CoA groups
From a microbiome point of view, why might eating trehalose be bad for you? How did the RT078 strain change so that cells could use trehalose? How does this strain become more virulent when trehalose is present?
Trehalose is a sugar that strains of C.difficile can live on and cause disease (recent food additive). Presence of trehalose created more toxins. RT708 has genes for a trehalose transporter (in membrane of cell), transports trehalose into cytoplasm of cell and used as energy. It had some extra genes, we don't know where they got it from.
How do bacteria move? How might this increase a pathogen's ability to cause disease?
Ways to Move: Flagella: by using a proton motive force Twitching using pili: pili can attach to each other and exchange DNA Gliding: using extracellular polysaccharides Axial filaments: internal flagella that make a corkscrew motion Will increase a pathogen's ability to cause disease because they can move into the host and are not stationary
Why should you re-cork you wine after you open it?
You want to remove the air or replace it with nitrogen. Once you open the bottle of wine and oxygen is there, the acetobacter can grow quickly. It will take the ethanol and produce acetic acid
How can microbes travel?
a. Flagella b. Cilia c. Gliding d. Fimbria e. Slime coats f. Magnetic forces