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BMSC 210 Midterm 1 | 100% Correct
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What are some properties of all cells? - ✔✔Growth, metabolism, and evolution What are properties of some cells? - ✔✔differentiation, communication, genetic exchange, motility What domain of life do marcroorganisms belong to? - ✔✔Eukarya How did the diversity of life arise? - ✔✔Through evolution Which encoding gene was/is slow to evolve? - ✔✔The gene encoding the small ribosomal subunit in both eukarya (18S) and Bacteria/Archaea (16S) Which domain is archaea most closely related to? - ✔✔Eukarya How is the phylogenetic tree created? - ✔✔By analyzing DNA sequences from each organism Which two domains of life are prokaryotic? - ✔✔Bacteria and Archaea What were the ancestors of multicellular organisms? - ✔✔Eukaryotic microorganisms What were the first two domains that diverged from LUCA? - ✔✔Bacteria and Archaea What did Archaea diverge into? - ✔✔Eukarya and Archaea What did Robert Hooke do and when? - ✔✔Wrote the first book devoted to microscopic observations in 1665
What did Anton van Leeuwenhoek do and when? - ✔✔He was the first to see bacteria in 1676 What did Ferdinand Cohn do and when? - ✔✔He was the first to see bacterial endospores, around the 1850s What did Louis Pasteur do and when? - ✔✔Disproved spontaneous generation theory in 1864
- also developed vaccines for rabies, anthrax, and chicken cholera, around 1885 What did Pasteur use to disprove spontaneous generation theory? - ✔✔A swan shaped flask What is number one of Koch's postulates? - ✔✔The suspected pathogen must be present in everything with the disease and absent from healthy animals What is number two of Koch's postulates? - ✔✔The suspected pathogen must be grown in a pure culture What is number three of Koch's postulates? - ✔✔The pure culture from the suspected pathogen must cause disease in a healthy animal What is number four of Koch's postulates? - ✔✔The suspected pathogen must be reisolated and shown to be the same as the original What is one of the effects of studying microbes? - ✔✔Deaths from infectious diseases have drastically decreased What does staining a microscope slide do? - ✔✔Improves contrast between features What is the power of light microscopy limited by? - ✔✔Resolution
What is fluorescence microscopy used for? - ✔✔To visualize specimens that fluoresce, either naturally or after they have been stained with a fluorescent dye. In what way would you use fluorescent microscopy? - ✔✔Counting the number of bacteria in a natural sample What does differential interference contrast microscopy use to create images? - ✔✔A polarizer to create two distinct beams of polarized light What type of image does differential interference contrast microscopy create? - ✔✔A 3-D one What structures would you visualize under differential interference contrast microscopy? - ✔✔Endospores, vacuoles, and granules How does atomic force microscopy generate an image? - ✔✔By placing a stylus close to a specimen and having a computer produce an images from the stylus's data How does confocal scanning laser microscopy generate a 3-D image? - ✔✔By coupling a fluorescence microcope to a laser source How does confocal scanning laser microscopy put together an image? - ✔✔By compiling multiple thin layers of a single specimen What do electron microscopes use to image structures? - ✔✔Electrons instead of photons What does a TEM allow visualization of? - ✔✔Structures at a molecular level, although the specimen must be very thin and stained How does SEM visualize a structure? - ✔✔By coating a cell with a heavy metal and having an electron beam scan it, can observe very large specimens
What does morphology mean? - ✔✔Cell shape What are the major cell morphologies? - ✔✔-Coccus: Spherical
- Rod: Cylindrical
- Spirillum: Spiral shaped What does morphology usually NOT predict? - ✔✔Physiology, ecology, phylogeny, etc What are some selective forces in a cell setting up morphology? - ✔✔-optimizing nutrient uptake
- swimming motility and gliding motility How does the size of prokaryotic cells compare to the size of eukaryotic cells? - ✔✔Prokaryotic cells can be both much smaller and much larger What are the advantages to being a small cell? - ✔✔Smaller surface to volume ratio, allows for greater nutrient uptake, and faster growth How does the S/V ratio change with radius? - ✔✔A larger radius leads to a smaller ratio, since area is r^ and volume is r^ What are the functions of the cytoplasmic membrane? - ✔✔-separate cytoplasm from the environment (permeability barrier)
- concentrate specific metabolites
- excrete waste products
- anchor proteins
- site of ETC, generates proton motive force What allows membranes to exist in many different forms? - ✔✔Variation in the groups attached to the glycerol backbone
- requires five proteins
- best studied system What does group translocation move? - ✔✔Glucose, fructose, and mannose What do Atp Binding Cassette systems transport? - ✔✔Organic compounds (i.e. sugars), inorganic nutrients( i.e.. sulphate), and trace metals What do ABC transporters display? - ✔✔High substrate specificity What kind of systems do gram negatives employ? - ✔✔Periplasmic binding proteins and ATP driven transport proteins What kind of systems do gram positives employ? - ✔✔substrate binding proteins and membrane transport proteins What are bacteria classified based on? - ✔✔Gram Stain: negative or positive What is the difference between gram negative and gram positive? - ✔✔They have a different cell wall structure Negative: peptidoglycan and outer membrane (two layers) Postive: peptidoglycan (one layer) What do gram positive bacteria appear after staining? - ✔✔Purple What do gram negative bacteria appear after staining? - ✔✔Red What is peptidoglycan made of? - ✔✔A polymer of two sugars, acetylglucosamine and acetylmuramic acid. The bonds between them are sensitive to lysosomes
What does peptidoglycan contain? - ✔✔Peptide crosslinks Which species contain some D amino acids in their peptide crosslinks? - ✔✔Bacteria, Archaea do not What do gram positive cell walls contain? - ✔✔90% peptidoglycan with Teichoic acids embedded
- lipoteichoic acids are covalently bound to membrane lipids Do all prokaryotes have cell walls? - ✔✔Hell Nah! What do gram negative cell walls contain? - ✔✔10% peptidoglycan, mostly made up of the outer membrane aka lipopolysaccharide layer What does the LPS layer contain? - ✔✔Core polysaccharides and O-Polysacchrides in a polymer What does the LPS replace and where? - ✔✔Most phospholipids in the outer half of the outer membrane What are endotoxins? - ✔✔The toxic component of the LPS What is an example of an endotoxin? - ✔✔Lipid A Moiety When is the lipid A component released? - ✔✔When gram negative cells are lysed What is the periplasm? - ✔✔space located between cytoplasmic and outer membranes What are porins? - ✔✔channels for movement of hydrophilic low-molecular-weight substances What are characteristics of archaea cell walls? - ✔✔No peptidoglycan and no outer membrane, instead made of pseudomurein in some Archaea
What are carbonate minerals? - ✔✔Barium, Strontium, and magnesium What are magnetosomes? - ✔✔magnetic storage inclusions What are gas vesicles? - ✔✔Spindle shaped, gas filled protein structures that give buoyancy to planktonic cells
- impermeable to water What is the structure of gas vesicles, how do they function? - ✔✔Made of proteins GvpA and GvpC, function by decreasing cell density What are endospores? - ✔✔resistive structures that resists adverse environmental conditions
- dormant bacteria, easily spread What are endospores present in? - ✔✔Only some gram positive bacteria What is the structure of endospores? - ✔✔Contains dipicolinic acid, enriched in calcium, with a core containing small acid soluble spore proteins What are flagella? - ✔✔Helical structures composed of flagellin that assist in swimming through rotational movement
- in bacteria What are the different arrangements of flagella? - ✔✔peritrichous, polar, lophotrichous What are flagella powered by? - ✔✔The proton motive force Where are the MS and C ring located? - ✔✔In the inner membrane
How do archaea flagella differ from bacterial? - ✔✔Archaea flagella are half the size What is made first in flagella synthesis? - ✔✔The outer MS ring, then other proteins, then the hook, then the cap, then the filament grows from the tip What is flagella rotational speed proportional to? - ✔✔The strength of the proton motive force How do cells with peritrichous flagella move? - ✔✔Slowly, in a straight line How do cells with polar flagella move? - ✔✔Rapidly, spinning around What is gliding motility? - ✔✔*flagella independent motility *slower and smoother than swimming *movement typically occurs along long axis of cell *requires surface contact *mechanisms: excretion of polysaccharide slime type IV pili gliding specific proteins What are taxis? - ✔✔Movement toward or away from a chemical or physical stimulus What do bacteria respond to? - ✔✔Temporal, not spatial differences in chemical concentration What senses attractants? - ✔✔Chemoreceptors What kind of behaviour do bacteria exhibit when they sense a stimulus? - ✔✔Directed run and tumble behaviour
What two carriers facilitate redox reactions without being consumed? - ✔✔NAD+ and NADH What are the substances with a high energy bond? - ✔✔-ATP: anhydride and ester bond
- PEP: anhydride bond
- G6P: ester bond
- Acetyl-CoA: thioester bond
- Acetyl phosphate: anhydride bond What two pathways are linked to glycolysis? - ✔✔Fermentation and Respiration How does fermentation produce ATP? - ✔✔Through substrate-level phosphorylation: ATP is produced directly How does respiration produce ATP? - ✔✔Oxidative phosphorylation: ATP is produced indirectly from the proton motive force A fermented substance is both a: - ✔✔electron donor and acceptor What is glycolysis? - ✔✔An anaerobic pathway for the catabolism of glucose What is generated during the creation of 1-3 BPG? - ✔✔Reducing power, which is used to convert pyruvate to lactate What would happen if pyruvate was not converted to lactate? - ✔✔Reduced NADH would build up and the cycle would stop How does substrate level phosphorylation work? - ✔✔A phosphate from a substrate is transferred to ADP to create ATP
What is the net yield of ATP for each glucose fermented to lactate? - ✔✔2 ATP How is respiration different from fermentation? - ✔✔Reducing power is transferred to a terminal election acceptor, rather than the end product of degradation What is the terminal electron acceptor in aerobes? - ✔✔O What does the movement of reducing power equal? - ✔✔Electron transport What is aerobic respiration? - ✔✔oxidation using O2 as the terminal electron acceptor What are NADH dehydrogenases? - ✔✔Proteins bound to the inside of the cytoplasmic membrane Bind to NADH and Accept 2 electrons and 2 protons that are passed to flavoproteins What are flavoproteins? - ✔✔Contain flavin prosthetic group that accepts 2 electrons and protons but donates only the electrons to the next protein in the chain What are cytochromes? - ✔✔-proteins that contain heme prosthetic groups
- they accept and donate a single electron via the iron in heme What are iron-sulfur proteins? - ✔✔clusters of iron and sulphur that carry electrons
- reduction potentials vary depending on number and position of atoms What are quinones? - ✔✔hydrophobic non-protein containing molecules that participate in electron transport accepts electrons and protons but pass along electrons only How are electron carriers ordered in the membrane? - ✔✔In terms of their electron potential
What are polysaccharides synthesized from? - ✔✔Activated glucose
- ADPG (glycogen precursor) and UDPG (glucose derivative precursor) What two pathways are amino acids synthesized from? - ✔✔Glycolysis and CAC How are fatty acids synthesized? - ✔✔2 carbons at a time an acyl carrier protein is involved as it holds the fatty acid as it is being synthesized What is the final assembly of lipids in bacteria and eukarya? - ✔✔Fatty acids are added to glycerol What is the final assembly of lipids in archaea? - ✔✔Phytanyl side chains are added to fatty acids
- phytanyl production is independent of fatty acid production What is each gene transcribed onto in eukaryotes? - ✔✔A single mRNA How are genes transcribed in prokaryotes? - ✔✔Multiple genes are transcribed onto a single mRNA What is coupled in prokaryotes? - ✔✔transcription and translation, producing proteins at a maximum rate What violates central dogma? - ✔✔Some viruses How is DNA packed in prokaryotes? - ✔✔Into circular supercoils What is needed for supercoiled DNA to form? - ✔✔One or both strands to be broken What element is common in prokaryotes but uncommon in eukaryotes? - ✔✔Plasmids
How does DNA replication occur in prokaryotes? - ✔✔-Synthesis is initiated at then origin of replication
- Replication forks continue synthesis in opposite directions
- Two chromosomal copies are released when the replication forks hit the terminus of replication What is a sigma factor? - ✔✔a protein needed only for initiation of RNA synthesis that binds with RNA polymerase What is the core promoter? - ✔✔The Pribnow Box What is termination of RNA synthesis governed by? - ✔✔A specific DNA sequence What are intrinsic terminators? - ✔✔transcription is terminated without any additional factors What is Rho-Dependent termination? - ✔✔Where the Rho protein causes a pause in transcription after it recognizes certain DNA sequences What is the unit of transcription? - ✔✔unit of chromosome bounded by sites where transcription of DNA to RNA is initiated and terminated What are the three types of rRNA? - ✔✔16S, 23S, and 5S True or False: All RNAs are translated - ✔✔False, rRNA and tRNA aren't Which RNAs are stable and which degrade quickly? - ✔✔tRNA and rRNA are stable, mRNA has a short half life How are prokaryote genes spread out? - ✔✔They are clustered together
How do bacteria grow? - ✔✔Exponentially, with short generation times What is a batch culture? - ✔✔a closed-system microbial culture of fixed volume What are the four phases of a cell population growth curve? - ✔✔-lag phase
- exponential phase
- stationary phase
- death phase What is a continuous culture? - ✔✔an open-system microbial culture of fixed volume What is a chemostat? - ✔✔a device for continuous culture What two factors can be controlled both independently and simultaneously? - ✔✔Growth rate and population density How can you control the growth rate? - ✔✔By altering the dilution rate: the rate at which fresh medium is pumped in and spent medium is pumped out How can you control population density? - ✔✔By controlling the concentration of a limiting nutrient What occurs in a batch culture? - ✔✔Growth conditions constantly change, so it's impossible to independently control both growth parameters What does too high a dilution rate result in? - ✔✔The organism washing out What does too low a dilution rate result in? - ✔✔The organism starving
What does increasing concentration of the limiting nutrient result in? - ✔✔Greater biomass but the same growth rate What are two ways of enumerating microbial cells? - ✔✔1. Microscopic observation
- Flow Cytometer What is a viable count? - ✔✔A measurement of a living, reproducing population
- spread plate method and pour plate method
- have to dilute mixture to get a countable number What is the great plate anomaly? - ✔✔*direct microscopic counts of natural samples revea far more organisms than those recoverable on plates becasue microscopic methods count dead cells whereas viable methods dont and different organisms have different requirements for growth What can spectrophotometry be used to measure? - ✔✔Microbial growth (optical density)
- doesn't destroy sample What conditions effect growth? - ✔✔-Temperature
- pH
- Osmolarity
- Oxygen availability What are cardinal temperatures? - ✔✔the minimum, optimum, and maximum temperatures at which an organism grows What are extremophiles? - ✔✔organisms that grow under very hot or very cold conditions What are psychrophiles? - ✔✔cold-loving microbes, always live in cold
