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78 Cards in this Set
- Front
- Back
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Name the 3 kingdoms and what things fall under each.
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1. Eukarya - true bacteria: plants, animals, protists (primitive animals, single celled), fungi (primitive plants and animals, molds, yeast, absorbs food to transport soluble compounds, require carbon in diet)
2. Bacteria - eubacteria = true bacteria (prokaryotes have no nucleus, but have a nucleoid, contains both DNA and RNA) 3. Archea - unusual bacteria = archeobacteria (grow in weird envrionments like hot srpings, high salt areas, acidic areas, have unusual cell wall composition) |
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What are the 4 divisions to classify bacteria?
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D1: gram neg - stains red (spirochetes: spiral shape, flexible, treponema pallidum)
D2: gram pos - stains blue (Mycobacteria: rods, thick waxy cell wall, resistant to drying, Mycobacterium tuberculosis; Micrococaceae: spheres, can clump, Staphylococcus, Streptococcus) D3: Bacteria without cell walls D4: Bacteria with unusual cell walls |
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What are some other characteristics used to identify bacteria?
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Cell morphology - shape, size
Motile/Non-motile - presence of flagella Colony color, shape, size Pathogenicity or not Biochemical properties (ability to produce enzyme) |
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How do you make an enriched/complex media and what makes it complex?
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Extract of beef muscle, heart, brain
Extract of yeast cells Milk protein breakdown into the lower molecular precursors Complex because the composition is never exactly known |
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How do you make a defined media and what makes it different from an enriched media?
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Glucose - carbon/energy
Nitrogen - amino acids Sulfur - disulfide bonds Phosphorus - DNA or RNA Common minerals - for cofactors for certain enzymes Trace minerals - required by some rxn's in small amounts Different from enriched because the composition is known |
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Why is a semi-solid media preferred over liquid media and how do you prepare one?
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Because liquid media mixed with stuff makes a mixed culture that's difficult for observing, but a semi-solid media mixed with stuff will make a pure culture, better for studying.
Melt agar at 100˙C and when it's still liquid, pour it into a plate and let it solidify at 41˙C. |
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What are the different types of sterilization?
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Dry heat - used for glass and metals; involves heating at 160-170˙C for 2 hours
Moist heat - used for liquids; involves an autoclave that increases temperature to 121˙C and heat to 15 PSI for 15 minutes Filtration - uses a sterile filter for liquids Incineration - used for things that couldn't be sterilized with any of the above methods; involves a flame inoculating wire Poison gas - ethylene oxide Radiation - gamma rays, x rays |
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How do you prepare the different types of stains?
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Simple - fix cells on slide -> add crystal violet dye -> cells take up dye -> wash excess dye
Negative - Dye will color the background but leave the cells white Gram stain - fix cells on slide -> crystal violet dye + iodine -> wash with alcohol bc it'll remove dye from gram neg cells -> add safranin so that gram neg cells will be red Acid fast - fix cells -> dye with heat -> decolorize with heat and alcohol -> most cells will be colorless, but gram pos cells will be red. |
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What are covalent bonds, ionic bonds, and hydrogen bonds? Give an example.
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Covalent bonds occur between two atoms when they share an electron pair - CH4.
Ionic bonds occur when one atom has to give up an electron and another atom accepts it (atoms with 1, 2, or 3 valence electrons generally give up their lone electron, and the ones with 5, 6, or 7 generally gain them) - NaCl Hydrogen bonds are very weak bonds often formed between Hydrogen and Oxygen or Hydrogen and Nitrogen - H2O |
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What is a functional group?
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Functional groups are small numbers of atoms in a larger molecule that give the molecule its chemical reactivity properties. They react the same way
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Describe the different functional groups.
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Alcohols (-OH): contains 2 or more -OH groups; the -OH has to be linked to a Carbon that linked to a Carbon or Hydrogen
Carbonyl (C=O): Aldehydes are at the end on the chains, Ketones are in the middle. Carboxyl (COOH): must be linked to a Carbon or Hydrogen; dissociates into a compound and a proton Phosphoryl (POOH): dissociates three different times into a proton and PO4. Amino (NH2): all amino acids are amines Sulfhydryl (-SH): like hydroxyl, but has Sulfur instead of Hydrogen |
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How do you form an ester?
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Alcohol + Acid --> Ester + H2O (involves dehydration synthesis)
Ester + H2O --> Alcohol + Acid (involves hydrolysis) |
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What is a stereoisomer?
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Stereoisomers are two molecules that have the same formula, same functional groups, but different shape. They're important because certain enzymes recognize different shapes
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What are the two types of stereoisomers?
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Enantiomers: have the same chemical formula, functional groups, but different geometry - they have non-identical mirror images that are not super imposable (one is D and the other is L)
Diastereoisomers: have the same chemical formula, and funtional groups, contain 2 or more asymmetric carbons, but only one of those carbons are arranged differently in space (both are D, but there's something different about the arrangement around one of the carbons) |
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What are the four low molecular weight precursors of macromolecules?
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Monosaccharides, Fatty acids, amino acids, and nucleotides
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Describe the two new linkages involved with mononucleotides.
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Glycosidic bonds: N-glycosidic (carbon-1 is linked to nitrogen), O-glycosidic (carbon-1 is linked to oxygen)
Anhydrides: product of condensation of two acid molecules - high energy and takes a lot of work in order to break them which will release a lot of energy |
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What are the different cell shapes and what is the advantage of knowing the shape of the cell?
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Coccus (cocci): spheres - single, diplo, clusters (staphylococcus), chains (streptococcus)
Bacillus (bacillus): rod, cylinder Spiral - rigid (spirilla or curved), flexible (spirochetes - several coils) |
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What are microorganisms?
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Microorganisms reproduce themselves faithfully (chromosome has to be copied exactly so there are no mutations) and the species continues to occupy its niche in the environment. They have the capacity to change genetically (genetic exchanges) to be able to respond to the changing environments.
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How do cells reproduce?
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Binary fission - They need to accumulate food, oxidize it to get energy, and convert it to get low molecular weight compounds, and then synthesize macromolecules before dividing.
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What are the components of a phospholipid bilayer?
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A cytoplasmic membrane is made of a phospholipid bilayer that's composed of fatty acid chains and phosphates, as well as embedded proteins.
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What are some characteristics of a phospholipid bilayer?
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Selectively permeable - only water can diffuse freely, but proteins and other things diffuse slowly and laterally, and may diffuse by using the embedded proteins
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Define isotonic, hypertonic, and hypotonic solutions. Which is the best for animals and bacterial cells?
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Isotonic - concentration of water and solute are equal both inside and outside of the cell; no net change of water
Hypertonic - Concentration of water outside the cell is low and solute concentration is high --> water will diffuse freely from higher concentration to lower (inside cell to outside causing cell to shrivel) Hypotonic - water concentration is higher outside cell than inside, solute concentration is lower outside cell than inside --> water will diffuse from outside cell to inside (causing cell to swell and burst) Animal cells need an isotonic environment for growth Bacterial cells like hypotonic because rigid cell walls. |
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What would happen to a bacterial cell if it were placed in a hypertonic environment?
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The cytoplasmic membrane will collapse and growth will stop because not enough water will be on the inside.
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What are the functions of the cytoplasmic membrane?
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Food accumulation - an active process in which a group of chemicals is translocated and gets chemically changed which will require energy.
Metabolic pathways - include the ETC that will drive chemiosmosis and ATP synthesis. Cell wall component synthesis - has peptidoglycan that will assemble the cell wall outside the cytoplasmic membrane Signal transduction (Chemotaxis) - senses change in the environment and will recognize and respond to the change Secretion - proteins have to actively be secreted |
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Describe the difference between a gram-positive and gram-negative cell.
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Gram-positive cell - has a very thick layer of peptidoglycan that goes all around the cell and accounts for the rigid cell structure.
Gram-negative cell - has a thin peptidoglycan layer and an outermembrane |
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What are the two rings that are repeated in a polysaccharide?
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N-Acetyl Glucosamine
N-Acetyl Muramic acid |
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How do interbridges form for a gram-negative cell and a gram-positive cell?
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For a gram-negative cell, the interbridge forms when a covalent bond is made between amino acid 3 of one side chain and amino acid 4 of the other side chain.
For a gram-positive cell, the interbridge forms when a penta glycene is made between the amino acid 3 of one side chain and amino acid 4 of the other. |
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What bond needs to be broken in order for an interbridge to occur?
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Peptide bond between the two D-Alanine needs to be broken so the 4th amino acid can be linked to the 3rd amino acid of the second chain
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What is the role of a flagella?
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Movement - they will sense food and move towards it, which will cause them to stumble less (or they will sense a repellent and move away from it)
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What's the difference between a gram-neg flagellum and a gram-pos flagellum?
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Gram-neg flagellum have 4 rings in the cytoplasmic membrane, peptidoglycan, and outer membrane.
Gram-pos flagellum only have the first 2 rings in the cytoplasmic membrane |
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What is the role of the rings in flagellum?
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Cytoplasmic membrane has two rings - 1) stationary, 2) rotates and spins flagellum
Outer membrane (for gram neg only) - allows filament to go through (unnecessary) |
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In what direction do flagellum move?
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Clockwise - they'll randomly tumble
Counter clockwise - they're swim forward. |
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What are the different kinds of movement?
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Swimming - extracellular flagella rotate
Flexing - flagellum located in perplasm rotates so the cell flexes as the flagellum rotates Gliding - Moving over solid surfaces without flagella; Adventurous = twitiching done by individual cells, Social = done by many cells in unison Swarming - depends on the flagellum, cells move in unison over a solid surface |
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What are pili?
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Pili = adhesive organelles that functions in attachment. Pili on cell will extend so that it can stick to something and than retract so it can move
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What are the differences between a prokaryote and a eukaryote?
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Eukaryotes - true nucleus, chromosomes in nuclear membrane, introns common, divide by mitosis, reproduce by meiosis, have mitochrondria and chloroplasts, cell walls exist in plants and fungi, ribosomes 80S, larger than prokaryotes
Prokaryotes - no nucleus, has nucleoid, rare introns, divide by binary fission, primitive sex, no mitochrondria or chloroplasts, cell walls are present with peptidoglycan, ribosomes 70S, smaller than eukaryotes |
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Why are endospores formed and explain the mechanism.
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Endospores are formed as a survival mechanism. They're dormant, inert, and durable. They resist chemicals that would cause overheating, drying, or radiation and formed by growing cells.
Nucleoid is replicated inside cell -> cell starts to seal off chomosome copy -> form 2 compartments -> spore coat assemebles around cell release endospore |
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Which type of bacterial cell is more prone to grow endospores?
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Gram-positive are the principle spore formers
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What is botulism?
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Spores form by germinating in an anaerobic environment to secrete neurotoxin.
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What are the two types of Anthrax?
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Cutaneous - spores enter body through wounds, germinate and grow locally
Pulmonary - spores are breathed, germinate and infect in the lungs, cause swelling and death |
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What is tetanus?
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Spores enter body through wounds, germinate and grow at site of infection and secrete neurotoxin that will spread through nerves to spinal cord
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Define catabolism and anabolism.
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Catabolism - breaking down complex molecules to simpler ones; releases energy
Anabolism - building of complex molecules from simpler ones; requires energy |
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What is Gibbs free energy?
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G = free energy - energy released in form able to do work
Neg delta G = exergonic, spontaneous, free energy released, equilibrium favors products Pos delta G = endergonic, non-spontaneous, free energy required |
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What do enzymes do?
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Enzymes speed up the reaction rate by binding to a substrate (that fits in the active site) and holds the substrate in enzymatic catalyric site-strain bonds to reduce the activation energy
They do NOT change free energy or equilibrium |
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What is a coenzyme?
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Coenzymes - small molecules that participate with enzymes to speed up a reaction; but non-specific.
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What is oxidation and reduction?
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Oxidation - loss of electron
Reduction - gain of electron If it donates/lost an electron, then it's the reducing agent and becomes oxidized. If it accepts/gains an electron, then it's the oxidizing agent and becomes reduced |
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Describe the NAD reaction.
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NAD + 2e- + 2H --> NADH + H
NADH + H will use electrons in ETC ("pool of reducing power") |
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What is ATP?
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Adenosine Triphosphate - involved in many reactions
Has an anhydride = high energy |
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Describe the first major pathway of metabolism.
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Glycolysis - puts in 2 ATP for every molecule of glucose, but yields 2 ATP in the beginning steps, so net is 0 until more ATP are made
What goes in: glucose, 2 ATP, 4 ADP, 2 PO4, 2 NAD+ What comes out: 2 pyruvates, 2 NADH + H, 2 ADP, 4 ATP. |
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Describe the second major pathway of metabolism.
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Aerobic Respiration - occurs when the terminal electron acceptor is oxygen
What goes in: pyruvate, 4NAD+, FAD, GDP, PO4 What comes out: 4 NADH + H, FADH2, GTP, 3 CO2, 3 H2O |
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Describe the third major pathway of metabolism.
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Fermentation - occurs when the terminal electron acceptor is not oxygen (anaerobic respiration)
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Describe both types of fermentation
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Lactic acid fermentation - formation of lactate
pyruvate and NADH + H goes in --> lactate and NAD+ comes out Ethanol fermentation - production of ethanol pyruvate and NADH + H goes in --> ethanol, NAD+, and CO2 comes out |
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What is substrate level phosphorylation?
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When ADP and an inorganic phosphate make ATP so that any reaction is free to use it
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what is oxidative phosphorylation?
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Requires a reducing power and a terminal electron acceptor (like O2 for respiration)
NAD+ --> NADH + H transfers electrons to the ETC, electron flow is coupled with ATP synthesis |
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Describe the ETC
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Electron Transport Chain - accepts electrons from NADH and FADH2; uses energy released in oxi/red reactions to energize membrane and synthesize ATP
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What does chemiosmosis do?
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Generates the proton motive force.
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What is the phototrophic mode of respiration?
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CO2 converts into organic compounds with energy provided by light. Electron flow is cyclic because there's no terminal electron acceptor.
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How can the 12 key central metabolites be synthesized?
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From glucose or CO2
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Describe the difference between obligate aerobic and obligate anaerobic.
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Obligate aerobic - always requires O2
Obligate anaerobic - cannot grow when O2 is present |
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Define facultative and aerotolerant anaerobic.
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Faculatative anaerobic - can grow with or without O2, but grow better with it because it can do respiration and has max energy yield with O2 as an electron acceptor.
Aerotolerant anaerobic - Grows equally well with or without O2 (doesn't matter) |
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State four -philes and the environments they grow best in.
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Psychrophiles - grow best in cold environments
Mesophiles - grow in common living temperatures Thermophiles - grow in warm temperatures Hyperthermophiles - grow in unusually hot temperatures |
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What is the equation to calculate the number of bacteria after n generations?
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N = No(2^n)
N = number of bacteria after n generations No = initial number of bacteria n = total number of generations |
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How do you calculate the number of generations (n)?
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n = t/g
n = number of generations t = time in hours g = generation time in hours/generation |
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What are 6 physical means of microbial control?
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Sterilization - complete killing or removal of bacteria using an autoclave
Pasteurization - kills most pathogens; at first it was heated for a longer time, but that denatures the proteins, so then changed it to heat for one second because less time will keep the proteins Desiccation - drying; kills HIV and gonorrhea, but lets endospores survive High osmotic pressure - salt/sugar Radiation - UV, X rays, gamma rays, but can cause mutagens and carcinogens Filtration - used to remove microbes from liquids |
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Describe the different types of chemical control.
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Disinfection - remove/kill most pathogens on inanimate objects
Antiseptic - chemical applied to body to kill most pathogens Bactericidal - kills bacteria Bacteriostatic - prevents bacterial growth Acids - food additives Alcohols - denatures proteins and extracts lipids Phenolics - lister Halogens - ex. HCl will react with DNA/RNA proteins and inactivates them Iodine - water purification Heavy metals - bad; enzyme poison Hydrogen Peroxide - reacts with DNA, RNA and proteins to destroy activity Ethylene Oxide - poisonous gas used to sterilize things that can't be put in an autoclave Formaldehyde - tissue preservative |
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What is chemotherapy?
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Drug treatment based on selective toxicity
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How is folic acid synthesized?
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Para amino benzoic acid (required in microbes) + enzymes and other precursors --> folic acid
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What happens when there's no folic acid?
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Microbes will stop growing
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What is sulfanilamide and why is it selective?
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It reacts with and inhibits one enzyme of folic acid synthesis
Selective because humans don't synthesize folic acid, which don't have targets for sulfal drugs |
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What was the first cure for TB?
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Streptomycin - serves as a functional protein synthesis inhibitor
(no longer used to treat TB) |
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What are some side effects to drugs?
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Toxicity, allergy, normal flora destruction, drug-resistant pathogen mutants
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How is HIV DNA synthesized from RNA?
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single-stranded RNA gets converted to DNA which is integrated into human chromosome using reverse transcriptase and low molecular weight DNA precursors which will then degrade RNA so that a second DNA strand can be synthesized
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What does AZT do?
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AZT with single-stranded RNA, reverse transcriptase, and low molecular weight precursors will inhibit HIV DNA and growth of the second strand cannot be extended
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Example of twitching.
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Nesseria gonorhoeae, Pseudomonas aeruginosa
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Example of social gliding.
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Myxococcus xanthus
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Rank the composition of a bacterial cell from most to least.
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Water -> Proteins -> RNA -> Ribosomes -> DNA/Peptidoglycan
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Name examples of bacteria that are cocci.
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Staphylococcus aereus
Staphylococcus epidermis Streptococcus pygenes Neiserria gonorrhae Neiserria meningitis Streptococcus pneumonia |
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Name examples of bacteria that are bacilli.
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Bacillus anthraxis
Chlostridiem botulinim Chlostridiem tetani Escherichia coli Microbacterium tuberculosis Myxococcus Xanthus Salmonella enterica |
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Name examples of bacteria that are spiral
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Trepdonema pallidum
Vibrio cholerae |
