MICROM 410

Who is credited with disproving the theory of spontaneous generation?
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Who is credited with disproving the theory of spontaneous generation?
Tyndall
True or false: the 16S rRNA sequence MUST be identical between two organisms for them to be considered the same species
False!
Define endosymbiotic theory
Origin of mitochondria and chloroplasts: they originated as a result of a symbiotic union between free living bacteria and ancestors of eukaryotic cells.
- Cyanobacteria evolved into chloroplasts in eukarya
- Proteobacteria evolved into mitochondria in eukarya
You have discovered a new organelle in the cells of the eukaryotic organism you are studying. What might you expect to find if the endosymbiotic theory applies to this new organelle?
The organelle has its own circular DNA. Phylogenetic analysis tells you that this organelle groups with the prokaryotes.
Some prokaryotic species have properties normally NOT found in prokaryotes. The same can be said for some eukaryotic species and eukaryotes. What is an example of this point?
Some eukaryotic species don't use a mitochondrion (which are absent) to generate energy.
True or false: the bilayer of prokaryotes is generally impermeable to uncharged, nonpolar molecules.
False! The phospholipid bilayer is generally impermeable to polar and charged molecules due to the hydrophilic head and hydrophobic tail.
You have isolated a prokaryotic species in the laboratory. When analyzing the cellular material, what sort of observations would lead you to believe you are dealing with an archaeal species?
- The membrane phospholipids have ether linkages.
- The prevalence of isoprene subunits in the cell membrane.
Characteristics of bacterial phospholipids:
- Phospholipids vary in length and degree of saturation of fatty acid side chains
- A phospholipid with short fatty acid side chains will make the membrane more fluid than one with long fatty acid side chains.
- They are amphipathic (have both polar & nonpolar parts)
True or false: the cell wall can influence permeability.
False!
What would you expect to find in the cell envelope/cell wall of Gram positive cells?
- A polymer containing subunits linked by phosphodiester bonds.
- Mature peptidoglycan that contains the amino acid glycine.
Define gram positivePURPLE, thick cell wall, stain is retained by the cell wall after washingDefine gram negativePINK, very thin cell wall, stain is washed away very easilyTrue or false: During peptidoglycan biosynthesis, a lactic acid group is added to UDP-NAG to produce UDP-NAM.True!True or false: During peptidoglycan biosynthesis, the enzyme carboxypeptidase forms peptide bonds between peptide side chains on different strands of peptidoglycan.False!True or false: During peptidoglycan biosynthesis, UDP-NAM is covalently linked to bactoprenol, which is recycled.True!True or false: During peptidoglycan biosynthesis in gram POSITIVE species, the interbridge is added to the peptidoglycan subunit prior to transport across the membrane.True!Which of the following antibiotics act within the CYTOPLASM of the cell?A. Cycloserine B. Penicillin C. Vancomycin D. Cephalosporins E. LysozymeWhich of the following are TRUE about pseudomurien? 1. All archaea use it in their cell walls. 2. It doesn't have peptide side chains. 3. It has a different glycosidic linkage than peptidoglycan. 4. It contains N-acetylglucosamine as one of its sugars. 5. It's also called an S-layer.3 and 4 :-)True or false: Capsules can protect a microbe from dessication (removal of moisture).True!True or false: The capsule contributes to pathogenesis.True! The capsule is really important for pathogenesis (encapsulated vs non encapsulated mouse experiment)You are studying magnetotactic bacteria present in a sample oof pond water. What kinds of findings would support your hunch that the microbe in question is magnetotatic?- Microscopy indicates that the cells harbor internal crystals surrounded by a membrane - Contains a string of magnetic particles composed of iron oxide - Orient bacterial swimming toward optimal oxygen concentrationWhich of the following is NOT an example of an electron transport chain (ETC) member? - Flavoproteins containing redox active Flavin mononucleotide - Cytochromes - Iron/Sulfur proteins that contain iron conjugated to a porphyrin ring - QuinonesIron/Sulfur proteins taht contain iron conjugated to a porphyrin ringWhich of the following is FALSE regarding chemolithotrophs? - They use an ETC - They do NOT use central metabolic pathways during growth - Hydrogen is a great energy source for some chemolithotrophs - Iron, Nitrogen, and Sulfur-containing inorganic compounds can be used as substrates for chemolithotrophic metabolism. - The use the F0F1 ATPase for generation of biochemical energy (ATP).They do NOT use central metabolic pathways during growthWhich of the following are TRUE about anaerobic respiration? 1. This type of metabolism does NOT involve an electron transport chain. 2. E. coli is incapable of anaerobic respiration. 3. It involves the use of a terminal electron acceptor other than oxygen. 4. It involves the use of the F0F1 ATPase for generation of biochemical energy (ATP).3 and 4True or false: The TCA cycle produces both CO2 and THREE of the essential precursors for biosynthesis.True! :-)True or false: One of the major purposes of the pentose phosphate pathway is to generate the precursors necessary to synthesize nucleic acids.True! :-)Tell me about central metabolic pathways idk how to form this as a question- the TCA cycle produces both CO2 and THREE of the essential precursors for biosynthesis - One of the major purposes of the pentose phosphate pathway is to generate the precursors necessary to synthesize nucleic acidsWhich of the following is TRUE regarding the Calvin cycle? - It is the only biochemical pathway that can be used to fix carbon. - Its products enter central metabolism at the level of the glycolytic pathway. - It generates quite a bit of ATP and reducing power. - It has two unique enzymes, citrate synthase and succinate dehydrogenase. - It is ONE way a phototroph can generate energy.Its products enter central metabolism at the level of the glycolytic pathway.The chromosomes of most bacteria and archaea are: (2 things, one has to do with shape and one relates to the sugar-phosphate backbone)- circular - have deoxyribose as part of their sugar-phosphate backboneDuring DNA replication in bacteria, the ____________ ____________ holding the two parental DNA strands together will be broken by _______ _______________ acting at the replication fork.hydrogen bonds; DNA helicaseTheory of spontaneous generationThe concept that living creatures could arise spontaneously, without parental organisms (this theory was eventually disproved by Tyndall and Pasteur's swan-necked flask experiment)Germ theory of diseaseThe theory that diseases are caused by microbes. Supported by John Snow's experimentsRobert KochThe founder of the scientific method of microbiologyPure culturea culture grown from a single "parental" cellKoch's PostulatesDefine the causative agent of disease. 1. The microbe is found in all cases of the disease but is absent from healthy individuals 2. The microbe can be isolated from the diseased host and grown in pure culture. 3. When the microbe is introduced into a healthy, susceptible host, the same disease occurs. 4. The same strain of microbe is obtained from the newly diseased host. SUMMARY: - requires pure culture - requires symptoms - must be able to detect pathogen - requires animal host w/ same diseaseDefine immunizationThe stimulation of an immune response by deliberate inoculation with an attenuated pathogenChemolithotrophs/lithotrophsorganisms that feed solely on INORGANIC mineralsGeochemical cyclingThe global interconversion of various inorganic and organic forms of elementsNitrogen fixationProcess of converting nitrogen gas into ammoniaEndosymbiosisWhen one partner population grows within the body of another organism, i.e. the partnership of a host organism with its associated endosymbionts, microbes that grow within a host body/cell.BiofilmsOrganized, multispecies community adhering to a surfaceProkaryotesNo nucleus: bacteria and archaeaEukaryotesContain a nucleus: algae, fungi, protozoaIf two organisms share more than _____% genetic similarity, they are considered the same species.95%16S rRNAacts as a molecular clock. the sequence divergence of variable regions can be used as a proxy of genetic relatedness (i.e. phylogenetic trees)True or false: 80% of prokaryotes are motileTrue!Cell membrane:- the site of energy generation (ATP synthase) - key location of important proteins (~200!) - permeability barrier & location os transport proteins - an effective barrier to polar and charged moleculesPhospholipidsFatty acids attached to glycerol backbone via ester linkages. They can vary based on the attached fatty acids and groups attached to the phosphate.Membrane phospholipid composition can vary based on _____________, ___________ ____________, and ________________ __________.temperature, acid stress, and starvation stressUnsaturated fatty acids vs saturated fatty acids (lipid bilayer)Unsaturated fatty acids have high permeability due to kinks in their structure (higher permeability, more fluid). Saturated fatty acids have lower permeability because they are straight.Hopanoids (bacteria only!)Exist between fatty acid side chains, limiting motions and stiffening structure. Helpful when the bacteria is experiencing acid stress or starvation stress! They are also considered evidence of early cellular life.True or false: archaea have tons of variation in their phospholipid side chain structuresTrue! Archaeal membranes are very rigid and well-supported.Importance of cell wall- Provides rigidity to resist lysis - May have a role in shape determination - Provides a barrier against toxic chemical and biological agents - Site of action of most antibiotics - A component of cell wall is immunostimulatory (determining self from non-self)Gram positive peptidoglycanlil thiccie! ~40 layers thiccccGram negative peptidoglycanskinny legend!! mariah carey who! she's SKINTY baby!!!!!!!! ~2 layers thickRibosomal RNA (rRNA)present in all living organisms, can be used to estimate how long ago two species diverged from one anotherLipopolysaccharides are super toxic. Of the following macromolecules, which is the most responsible for the toxic effects of LPSs? - O-antigen polysaccharide - Lipid A - Disaccharide phosphate - Fatty acids - Core polysaccharideLipid ATrue or false: bacterial membranes contain proteins and phospholipids in the greatest abundance.True!ArabinogalactanAn important structural component of the mycobacterial cell wall, more importantly a good target for anti-mycobacterial drugs because it connects to, and anchors, the mycolic acid component of the cell wall.Penicillin (directly or indirectly) targets:- Cell wall synthesis - Cross-linkig of peptidoglycan peptides - Transpeptidase activityStromatolitesOldest known fossils formed from many layers of (photoautotrophic) bacteria and sediment.What are the two basic subunits of peptidoglycan?NAG and NAMWhat links the two basic subunits of peptidoglycan?Beta-1,4-linkageWhat enzyme cleaves the beta-1,4 linkage in peptidoglycan?lysozyme! This degrades the cell wall of bacteria.How is NAM different from NAG?NAM has a lactic acid group, which forms a link to the pentapeptide under it.Where does cross-linking occur in peptidoglycan?3rd position: mDap in gram negative and L-lysine in gram positiveTrue or false: the peptide side chain attached to NAM is cross-linked, which DECREASES stability of peptidoglycanFalse, it increases stability!True or false: Cross-bridge formation can be blocked or inhibited by antibioticsTrue!Peptidoglycan biosynthesis:1. Make subunit inside cytoplasm 2. Get it across the membrane 3. Insert it into exiting peptidoglycan (PG)