Microbial Physiology Chp 1
What is the difference between a protein & a glycoprotein?
A glycoprotein has an amino acid that is covalently bonded to a carbohydrate (sugar) called a polypeptide side chain.
What is the cytoskeleton of the cell?
A microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence
What are the two parts of the flagllem motor?
A non-rotating part called the "stator" made of MotA & MotB The rotating part called the "rotor" made up of FliG proteins that transmit torque to MS ring by interacting with MOT.
What is the nucleoid?
A nucleoid is only in prokaryotic cells & is the site of DNA & RNA synthesis. It is unbounded by a membrane, tightly coiled, with one chromosome.
What is Type 1 Pili?
A pilus that can be blocked by the addition of mannose to the medium. These pili are then called Type 1 Pili or "mannose sensative".
Which type of bacteria has the flagellar structure of vibrio cholera?
Spirochaetes, which also contains a sheath (like Vibrio cholerae), but is composed or protein, instead of LPS. Even with this unique characteristic, the flagella is still very similar to other bacteria.
How is "swarming" advantageous to flagella?
Swarming allows bacterial populations to rapidly spread as multi-cellular populations, rather than as single cells, over a wet, solid surface as in biofilms.
What is the main advantage to having a cell wall?
As the cell wall lies on top of the cell membrane, it protects the cell from bursting due to turgor pressure.
Of the three domains, which has a cell wall?
Bacteria & Archaea have cell walls. Eucarya is the only one without a cell wall.
What proteins are involved directly in the movement of protons H+?
Mot A & Mot B These proteins actually drive the flagellar motor causing rotation of the filament
What is Type 4 (IV) Pili?
Type IV Pili Type are found on Neisseria gonorrhoeae bacteria & are vital to the binding of the upper urinary tract.
What are two different ways operons are controlled to limit the amount of proteins being made?
1. Proteins can bind to the Operator Site which prevents RNA Polymerase from bind to the promoter. 2. Sigma factors can attach the the RNA Polymerase & determine which genes will be transcribed or which genes NOT to transcribe.
What is the function of Halorhodopsin?
A chloride pump used to accumulate chloride intracellularly to maintain osmotic stability.
What substances are attached to the backbone of Teichoic acid?
Alanine, Glucose or NAG are attached to the backbone.
What is the difference between the Bacteria & Archaea cell wall?
Bacteria cell walls are composed of peptidoglycan. Archaea cell walls DO NOT contain peptidoglycan, but what is commonly called pseudo-peptidoglycan.
Why does Bacteria & Archaea need cell walls?
Because Bacteria & Archaea organisms live in hypotonic & hypertonic environments where without a cell wall they would burst or die. The cell wall protects them from these unfriendly environments.
Is the S-layer found in both Gram Negative or Gram Positive?
Both G+ & G-!
Where are the lipoproteins located on Gram Negative bacteria?
Murein Lipoprotein anchors outer membrane to cell wall. The amino end of the protein is bound to the lipid The carboxy end is bonded to the cell wall
Which pathogenic bacteria is associated with "Walking Pneumonia"?
Mycoplasma!
Multienzyme complexes in the cytoplasm produce what kinds of reactions?
Pyruvate dehydrogenase: oxidizes pyruvic acid to acetyla-CoA & CO2. Alpha-ketoglutarate dehydrogenase complex: oxidizes a-ketoglutarate to succinyl-coenzyme A (acetyl-SCoA) & CO2.
If you put two different bacteria in a centrifuge, one with a slime layer & the other with a capsule, which bacterium would still have their glycocalyx?
The capsule, because it's more organized (as thus is more attached to the surface of the bacterium) than the slime layer.
What is the average salt concentration in a cell?
0.85 -0.90 concentration of salt. It's isotonic. i.e red blood cells can survive in this saline concentration.
What are 3 major functions of Pili?
1. Attachment to surfaces, including animal cells. 2. Motility through gliding or twitching. 3. Transfer of DNA between cells (sex pili)
What are Mollicutes?
A class of very small bacteria without cell walls that include Spiroplasma, Mycoplasma & Acholeplasma.
What are intracytoplasmic membranes?
A continuous specialized physiological membrane with specific functions usually attached to the plasma membrane of prokaryotic cells.
What is an Operon?
A genetic regulatory system found in bacteria in which genes coding for functionally related proteins are clustered along the DNA. A typical operon consists of a group of structural genes that code for enzymes involved in a metabolic pathway, such as the biosynthesis of an amino acid.
What is a promoter?
A promoter is a region of DNA that initiates transcription of a particular gene. It is the site where the RNA Polymerase lands, which is at the beginning, then moves along & starts to transcribe the mRNA from each gene.
What are Operon's made of?
A set of genes with a single promoter.
What is the glycocalyx of Prokaryotes?
A viscous covering surrounding a cell. In bacteria, it may appear as a capsule or a slime layer The structure is actually outside the cell wall
What are the 3 main roles of the glycocalyx?
Adhesion: Gives bacteria higher concentrations of nutrients on surfaces. Protection from phagocytosis: gives more virulence to the cell Prevent dehydration: polyanionic polysaccharies are heavily hydrated.
Where does photosynthesis take place in bacteria such as Chlorobium?
Although Chlorobium's inclusion bodies (Chlorosomes) contain photopigments, the PHOTOSYNTHETIC REACTION CENTERS are located in the cell membrane where photosynthesis actually takes place.
What would be the advantage to putting a charge on the phospholipid?
An ionic bond, which would allow the phospholipid of the cell membrane to stick to other proteins by having those ionic properties.
How is Archaea flagella different than Bacteria flagella?
Appear to be less complex and show no sequence homology with bacteria but have similar sequence homology at the N-terminal end among different Archaea
What is the function of Aquaporins?
Aquaporins, or water channels, increase the rate of permeability for water in the cell membrane. Without the water channels, water typically moves across the membrane slowly.
What type of microorganisms have gas vesicles?
Aquatic bacteria such as cyanobacteria, photosynthetic bacteria, & some archaea.
What is the initial amino acid used for Bacteria, Archaea & Eucarya?
Archaea & Eucarya use Methionine to initiate protein creation, but Bacteria uses a alternate form of Methionine called Formylmethionine.
What is the difference in metabolic pathways in Archaea & Bacteria?
Archaea are very metabolically diverse, so they are hard to generalize. Archaea DO NOT use glycolysis pathway to break down glucose. Many archaea do not have functional Kreb's cycle pathways, but some do.
Does Bacteria or Archaea, typically live in extreme environments?
Archaea commonly lives in extreme environments. i.e Rift vents in the deep sea at temperatures well over 100 degrees Celsius. Acidic or Alkalized waters. Digestive tracts of animals. Hyepersaline waters (Salt Lake)
Are Archaeal or Bacterial ribosomes similar to Eukaryotic ribosomes?
Archaea ribsomes resemble Eukaryotic ribosomes. Both are of their ribosomes are NOT sensative to certain protein synthesis inhibitors or antibiotics. Both start with Methionine instead of Formylmethionine for protein synthesis.
How are the sugars linked differently in Pseudo-peptidoglycan than normal peptidoglycan?
Archaea's peptidoglycan sugars are linked Beta-1, 3 instead of Beta-1, 4. Also, peptides in the cross link are only L-amino acids (normal form, no D!) There is NO NAM! It's N-acetyltalosamuronic acid instead.
What difference in RNA Polymerase do Archaea & Bacteria have?
Archaeal RNA Polymerase have 8-10 subunits, whereas Bacterial RNA Polymerase only has 4.
What are the three Domain's in biology?
Bacteria Archaea Eucarya
What is the significance of FliC protein also being an antigen?
Because FliC can be an antigen, it allows the body to detect a bacterium via the immune response. The IR can then attack & destroy the bacterium. Also, the antigen can be used to identify certain strains of bacteria in food.
How is the criteria measured for the organization of the glycocalyx?
By electro-spectroscopy, & by how difficult it is to remove from the cell. The more difficult it is to remove, the more organized it is.
How is the "tumble" motion of flagella advantageous to the bacteria?
By reversing the direction of movement, it can provide more environmental security. The flagella will receive signals from proteins to warn against harmful environments such as toxins or acids.
How does the Gram Negative Peptidoglycan differ from Gram Positive?
Can be isolated as a single pure sac Cross-linking direct Diamino is usually Diaminopipelic acid (DAP)
How can the Cytosol be isolated?
Can be isolated in a diluted form as the supernatant after broken cell extracts have been centrifuged at 105,000 x G for 1-2 hours which produce sediments made up of DNA, ribosomes, protein aggregates & membrane fragments.
What chemical disruptions affect Gram Positive?
Cell wall is disrupted by Lysozymes Penicillin & Sulfonamide Anionic Detergents
What type of structure does the Gram Positive bacteria have, that differs from the Gram Negative structure?
Cell wall is thick Peptidoglycan is multi-layered Teichoic Acids Lipoteichoic Acids Glycolipids
What type of structure does the Gram Negative bacteria have, that differs from the Gram Positive structure?
Cell wall is thin Peptidoglycan is single-layered Periplasmic space Outerlayer with porins LPS Endotoxins
What are major differences between Archaea & Bacteria?
Cell walls are made up of different material Environments Lipids in cell membrane Genetic Metabolic pathways
Other than cell walls, what other substances are beta-1,4 bonds found?
Cellulose!
What substances can block pili attachment?
Certain monosaccharides, oligosaccharides, galactose, or mannose may block pili attachment.
What bacteria are associated with Chlorosomes?
Chlorosomes inclusion bodies are mostly found in the photosynthetic organism "Green Sulfur Bacteria" or Chlorobium. Recently found in green photosynthetic bacterium Chloroflexus.
What does the second class of operons in flagella do?
Class 2 genes have operons are for the basal body, hook, & sigma factor (FliA) for Class 3 genes.
What does the third class of operons in flagella do?
Class 3 genes are required for flagellin monomer synthesis for the genes fliC (flagellin monomer protein) and MotA and MotB
What are Porins?
Porins are proteins in the outer membrane of Gram Negative bacteria that act as hydrophilic channels for sugars and ions.
What are Magnetosomes?
Contain crystals of magnetite (Fe3O4), each crystal surrounded by complex membrane of phospholipid and protein. They influence bacteria's direction of swimming with respect to the earth's magnetic field. Cool!
What is a severe, & many times fatal symptom of vibrio cholera?
Continual diarrhea. A person infected with that bacteria can poop 20 liters a day. It's not the bacteria that directly kills you, its the dehydration of loosing so many fluids. This is especially dangerous in children.
How does the Gram Positive Peptidoglycan differ from Gram Negative?
Covalently bonded to various polysaccharides and teichoic acids. Because of numerous bonds, cannot isolated in pure form. Cross-linking is by peptide bridge Diamino is sometimes DAP
Which proteins facilitate the bending of the coiled DNA in prokaryotic cells?
DNA in the nucleoid is not bound by a membrane, but is connected to the proteins HU, IHF, H-NS & Fis that create the coiling of prokaryotic DNA. Some of these proteins also help with gene expression.
What is the Sex Pili mechanism for transferring DNA from one sex to another?
DNA is transferred through the point of contact between the cells by pilus depolymerization, & NOT through the sex pilus.
What are the major similarities between Archaea & Bacteria?
Domains Prokaryotes, single-celled organisms. Cell walls Almost identical under a microscope. Reproduce using binary fission Flagella for motion.
Is Mycobacteria hydrophobic or hydrophillic?
Due to it's waxy lipid contents & being composed of 60 carbons, its very hydrophobic!
What would happen to E. coli if it lost the oligosaccharide (O antigen) & the core from its LPS?
E. coli would have an increased sensitivity to hydrophobic compounds such as antibiotics, bile salts & hydrophobic dyes such as eosin & methylene blue. Thus the bacteria would be weakened & more likely to die.
What chemical disruptions affect Gram Negative?
Environmental/Physical Streptomycin, Chloramphenicol & Tetracycline Sodium Azide
Which domains are sensitive to dipetheria toxin? How come?
Eucarya & Archaea, because they use Methionine to initiate protein synthesis which helps them not be sensitive to certain antibiotics, it does make them sensitive to dipertheria toxin, whereas Bacteria is NOT sensitive to the toxin, but IS sensitive to those other antibiotics.
What are the three major phenotypes of Archaea?
Euryarchaeota -Methanogenic -Halophilic Crenarchaeota -Thermophilic
What are the characteristics of Halophiles?
Extreme Halophiles or Euryarchaeota require 3-5 M NaCl concentrations (3x more salty than ocean) They include Bacteriorhodopsin or Halorhodopsin - light-driven H+ or Cl- pumps Halophiles in Greek means "salt-loving".
What are the characteristics of Extreme Thermophiles (Crenarchaeota)?
Extremely Thermophilic (Crenarchaeota) GROW at temperatures between 55-100ºC They use inorganic sulfur as an electron donor or acceptor. Also a third phyla, Korarchaeota is thermophilic and a fourth phyla, Nanoarchaeota from submarine hot vent.
What is bacterial Flagella?
Flagella are helical shaped structures which are composed of proteins called flagellin. Bacterial flagella are long, thin, whip like appendages that move the bacteria towards nutrients & other attractants in liquid.
What is FliC?
FliC is the flagellin protein monomer which makes up the long filament. It is the most abundant protein in flegella & tends to be an antigen by inducing an immune response.
What protein(s) make up the M-S ring?
FliF
Which of the proteins in the C ring interact directly with MOT? What does that interaction cause?
FliG interacts DIRECTLY with MOT to transmit the torque to the M-S ring.
What are the proteins that make up the C ring of flagella?
FliG, FliM, and FliN They are considered the motor switch that usually turns counter-clockwise but can reverse.
What is a gas vesicle made up of & what is its function?
Gas vesicles are hollow, spindle shaped structures filled with gas made up of a small highly conserved hydrophobic protein (GsvA) surrounding itself as a coat. It's allows organisms to float in lakes/ponds at depths that support growth from light, temperature or nutrients.
What does the first class of operons in flagella do?
Genes in class 1 (flhDC) compromise of operons that encode transcription activators for Class 2 genes.
What is the motility of Mycolasmas?
Gliding
What is considered the backbone of the peptidoglycan stucture?
Glycan = NAG & NAM.
What is the structure of glycerol? What is it the backbone of?
Glycerol is the backbone of phospholipids. It is one of the simplest forms of sugar, with only 3 carbons.
Does Gram Positive or Gram Negative have a more complex cell wall?
Gram Positive! The reason for it's complexity is unknown.
Is Mycobacteria Gram Positive or Gram Negative?
Gram Positive, but it doesn't gram stain due to the waxy mycolic acid covering.
What method in the lab is used to distinguish Gram Negative & Gram Positive?
Gram stains distinguishes two types of cell walls as well as the presence of an outer membrane. Gram Positive stains purple (except mycobacteria) Gram Negative stains Pink
What are Granules? How do they benefit organisms?
Granules store energy for many bacteria with substances such as: Poly-Beta-hydroxybutarate (PHB) Glycogen Polyphosphate Sulfur
Where does the flagella structure start to grow?
Growth occurs through distal end. Flagellin subunits travel thru a hollow core in the basal body, hook, & filament, then added at the distal tip. It's important for HAP2 (FliD) to move over for flagellum growth, but by stay attached to close up again.
What is used to form the junction between the hook and the filament (flagellin polymer)?
HAP1 & HAP3 are used to form & connect the hook & the filament.
What is another name for HAP1? What is another name for HAP3?
HAP1 = FlgK HAP3 = FlgL
What is the role of HAP2 in the Flagella? What is it's other name?
HAP2 caps the flagellar filament. HAP2 = FliD
How does the differences in Archaea cell membranes enhance it's survival in comparison to bacterial & eukaryotic cell membranes?
Having a more complex hyrdocarbon tail with branched isoprene chain & a monolayer allows Archaea to withstand environments with higher temperatures, & larger pH fluctuations.
What is an HAP?
Hook Associated Protein
What is found in the isolated cytosol that's incredibly important to the metabolism of the cell?
In the supernatant are soluble enzymes of various biochemical pathways important for metabolism. Most major reactions done in the cell are done by these enzymes. The protein concentration is very high in the cytosol.
What are inclusion bodies & where are they found in the cell?
Inclusion bodies are specialized compartments in the cytoplasm. They are NOT surround by a lipid bi-layer-protein like eukaryotes, but can contain a coat or membrane.
What substances are excluded from crossing the cell membrane without a transporter?
Ions cannot cross the cell membrane without a transport channel!
In broad terms, how does the lysozyme help protect the human body from infectious bacteria?
It generally helps the body from invasion of bacteria via tears, saliva, etc.
Do glycocalyx exist on prokaryotic cells only? Or does it include Eukaryotic cells too?
It includes both Prokaryotic & Eukaryotic.
What is the function of Bacteriorhodopsin?
It is a proton pump that creates an electrochemical proton gradient that is used to drive ATP synthesis.
Why is attachment for a bacterium via the glycocalyx important?
It serves as a virulence factor, so it can attach to tissues & attack. Allows the bacterium a better chance at catching nutrients in a stationary period, than swimming around in the media.
Why would gas vesicles that help with buoyancy be a benefit to microorganisms?
It would be especially helpful to microbes that are photosynthetic. Floating would allow it to be shallow enough in the water to receive light.
What is ribitol phosphate?
It's a sugar with 5 carbons & a phosphate.
Is it more advantageous for a cell wall to have Beta-1,3 or Beta-1,4 bonds? Why?
It's structurally more beneficial to have a Beta-1,4 bond in cell walls because its strong, & harder to break.
Are intracytoplasmic membranes synthesized independent of the cell membrane?
Its unknown! ???
What is the cell wall structure of Mycobacterium?
Its very similar to Gram + cell wall in that it's very thick & complex, but with less polysaccharides & more complex lipids with the waxy mycolic acids covering. The wall can be composed of 60 carbons & is very hydrophobic.
Which protein is associated with the L ring & P ring?
L ring =FlgH P ring = FlgI
What is the common form of amino acid, L or D?
L! The famous 20 amino acids used to make protein are all in the L-form.
How are Archaea lipids different than Bacteria & Eukaryotes?
Lack fatty acids Ether linkages instead of ester Branched isoprene chains L-glycerol instead of D formation
What are Carboxysomes? What type of bacteria are they found in?
Large polyhedral inclusions found in strict autotrophs which grow with CO2 as their only source of energy. RUBISCO is found inside but all autotrophs have carboxysomes
What is the pathway of photosynthesis in Chlorobium?
Light is absorbed by pigments in chlorosomes & energy is transmitted to the reaction centers in the cell membrane where photosynthesis takes place.
What is Lipid A?
Lipid A is an endotoxin. Only when the cell dies, does an "endo" toxin get released into the media.
What are the 3 parts of LPS?
Lipid A that's embedded in outer membrane Core O-antigen, which is a repeating oligiosaccharide
How are the linkages & lipids organized in Archaea cell membranes?
Lipids are isopranoid alcohols with either 20 or 40 carbons Ether linked to one glycerol to form monoglycerol diether (A) or two glycerols to form diglycerol tetraethers (B). The two tails can be linked!
In a Gram Negative cell, what does the Outer Membrane contain?
Lipopolysacharrides, LPS!
How does Lysozyme affect peptidoglycan?
Lysozyme target the COVALENT BONDS linking sugars NAG & NAM of the cell wall's peptidoglycan, which breaks it apart which results in weakening the cell wall structure.
What is MOT?
MOT is the proton channel consisting of Mot A and Mot B proteins.
What is the function of Mechanosensitive channels?
Mechanosensitive channels regulate solute export and protect against hypo-osmotic shock.
What are the characteristics of Methanogenic (Euryarchaeota)?
Methanogenic or Euryarchaeota produce methane by REDUCING carbon dioxide or by converting acetate to carbon dioxide and methane. i.e. live in the gut of cattle
Are Mollicutes more closely related to Gram Negative or Gram Positive?
Mollicutes are more closely related to GRAM POSITIVE, although they stain PINK, instead of purple!
What are the four different arrangements of Flagella?
Mono polar (single flagellum at one pole) or bipolar (single flagellum at each pole). Lophotrichous refers to a bundle of flagella at a single pole. Amphitrichous refers to a bundle of flagella at each pole. Peritrichous refers to flagella surrounding the cell but coalesce into a trailing bundle.
Where are monomers transported in the flagella?
Monomers are transported through the hollow filament and assembled as the capping protein moves outward.
What is bacteria's advantage to having a glycocalyx?
More virulenence due to hiding from IR Protection from desiccation, which is harsh environments Attachment Nutrient acquisition
Why does Mycobacteria NOT gram stain?
Mycobacteria contains mycolic acids, which have a waxy lipid covering, external to the cell wall that will not allow for a purple staining. This resistance to dye is called "acid-fast".
What exactly is the mycolic acid of Mycobacteria
Mycolic acid is a 3-hydroxy fatty acid with 2 alkyl branches with one branch as a hydrocarbon side chain of 24 carbons, & the second branch is a hydroxylated hydrocarbon with 60 carbons.
Peptide bridges are associated with cross-linking with NAG or NAM?
NAM! (N-acetylmuramic acid.)
Is Flagellin identical in all bacteria? Is it identical through the same species of a particular bacteria?
No & no! Flagellin is not the same in all bacteria. There can even be different types of flagellin in the exact same bacteria species.
Does Mycoplasma have peptidoglycan?
No!
Is there an L & P ring in gram positive bacterial flagellum?
No!
Do the same antibiotics that affect Bacteria, also affect Archaea?
No! Although bacteria's ribosomes are sensitive to the antibiotics chloramphenicol, strepomycin & kanamycin, it has virtually zero affect on Archaea.
Does Bacteria commonly change its shape in response to its environment?
No! Bacteria is usually monomorphic, but can be pleomorphic in rare cases.
Do Archaea always have lipid bilayers to their cell membrane?
No! Unlike Eucarya & Bacteria; Archaea can have monolayers. These monolayers are very common in extreme thermophiles.
What are major characteristics Prokaryotes have, that differ from Eukaryotes?
Nucleoid w/ 1 looped chromosome in cytoplasm. Cell walls. No histones or organelles. Binary fission
What are major characteristics of Eukaryotes that differ from Prokaryotes?
Nucleus w/ paired chromosomes Do not have cell walls but have polysaccharides Include histones & organelles Mitosis
What are the proteins for Porins & how do they contribute to regulation?
OmpF = largest pore size OmpC= non-specific PhoE = greater specificity for phosphate & increases under phosphate limiting conditions. Considered non-specific, but regulate by SIZE.
What is the function of an Operon?
Operons enable protein synthesis to be controlled coordinately in response to the needs of the cell. By providing the means to produce proteins only when and where they are required, the operon allows the cell to conserve energy (which is an important part of an organism's life strategy).
Where are prokaryotic flagella found in relation to the cell?
Outside the cell wall, attached to the cell at one end, while free at the other. This attachment to the wall & membrane of the cell is done by a protein hook which connects filament to the motor portion of the flagemmum called the the basal body.
What type of activities from enzymes occur in the periplasmic space of the cell wall?
Oxidation reduction reactions Osmotic regulation Solute transport Protein secretion Hydrolytic activities with nucleases and phosphatases
What would be the result of mutated motA & motB genes in flagellum?
Paralyzed flagellum.
How does Penicillin affect peptidoglycan?
Penicillin prevents the peptide bridges from forming during a GROWTH PHASE, which causes instability in the formation of a cell wall. Turgor pressure will decimate this poorly constructed cell wall & effectively kill the bacteria.
What is the cell wall material made up of?
Peptidoglycan or Murien. It is glycan chains cross-linked with peptides.
What is another term for Fimbriae?
Pili
Which part of the phospholipids are hydrophobic & hydrophilic?
Polar ends = the "polar-head", interact with water, hydrophilic Nonpolar ends = fatty acid tails, insoluble in water, hydrophobic
What is a Capsule composed of?
Polysaccahrides or proteins. The polysaccharide can be made of a single type of monosaccharide, or several different sugars.
Are gas vesicles membrane or protein structures?
Protein structures!
How are the proteins distinguished in the bacterial cell membrane?
Proteins are either integral or peripheral, & distinguished by removal by salt versus detergent Integral proteins removal from DETERGENTS. Peripheral proteins removal from SALTS or pH.
What is the prokaryotic "cytoskeleton" made up of?
Proteins called... FtsZ: resembles tubulin (microtubules) MreB: resembles actin Crescentin: appears similar to intermediate filaments Prokaryotes have proteins similar to the classic type of Eukayotic cytoskeleton proteins.
What is the S Layer composed of?
Proteins or glycoproeins that have a tile-like appearance.
What are ribosomes & what is their function?
Ribosomes are the sites of protein synthesis. Composed of ribonucleoprotein particles, 50 different proteins & 3 different types of RNA (23S, 16S & 5S).
What 4 forms can the glycocalyx take on a cell?
S Layer (can be the cell wall for Archaea) Capsule Slime Layer Loose Network of fibrils
What are Pili?
Small hair-like protein fibrils that extend from the cell.
What is the important type of pili used to attach to the intestinal lining? Would a drastic mutation effect it's ability to attach to those tissues?
Tcp or "toxic coregulated pili", are necessary for Vibrio cholera to attach to the intestinal lining. Yes! A dramatic mutation would cause the vibrio cholera to loose its pathogenicity.
Where are Teichoic acids found? In what type of Bacteria?
Teichoic acids are linked to the peptidoglycan via a phosphate to the C6 hydroxyl of the NAM. They are associated with Gram Positive bacteria.
What two possibilities do Teichoic acids have for a back bone?
Teichoic acids have either GLYCEROL or RIBITOL phosphate for backbones.
Which RNA Polymerase of Archaea & Bacteria, is more closely related to the Eukaryotic RNA Polyermase? What are the two reasons for the similarities.
The 2 reasosn Archaeal RNA Polymerase resembles Eukaryotic RNA Polymerase is because both have similar number of subunits (eukaryotic has 10-12, archaea has 8-10) & because both are NOT sensative to Rifampicin, unlike Bacteria.
What was the original name of Syphilis? What is the bacterial name?
The Great Pox, because it was always fatal. Treponema pallidum
What is the Hook from a flagella made up of?
The Hook protein is made up of many copies of FlgE proteins. The gene of FlgE is flgE.
Where is the LPS located in the cell wall?
The LPS is in the outer leaflet of the outer membrane
What are important protective functions of the LPS in Gram Negative bacteria?
The LPS serves as an important HYDROPHOBIC barrier to bile salts, as well as hydrophobic dyes. The lipid A portion contains only saturated fatty acids increasing its impermeability by its rigidity.
While Gram Negative bacteria are swimming around in the harsh environment of the intestines, what protects them against the bile salts?
The LPS.
What is the order of assembly of the Flagella? What's formed first, what's created last?
The M/S/C rings are made first. Rod --> hook --> P/L rings as the hook is completed. Flagellin monomers are transported and the filament is assembled. MotA and MotB are assembled late.
What type up charge does the Polar head of a phospholipid have?
The Polar & hydrophilic section of the fatty acid can have a positive, neutral, or negative charge.
What is the Sex Pili function? What is it coded by?
The Sex pili is coded by the F plasmid, attach from the donor to recipient cell for the purpose of transferring plasmid DNA. The recipient cell also becomes a potential donor cell.
What is an unusual feature about the LPS's distribution in the cell wall?
The asymmetric distribution of lipids in a membrane is unusual in bacteria.
What is the basal body of flagellum?
The basal body is embedded in the cell membrane & contains 3 stacked rings, C, M & S & the Central Rod. In gram negative bacterial, it also includes L & P rings.
What are bile salts?
The bile produced from pancreatic enzymes & the gall bladder. They are important in the digestions of lipids.
Why are Capsules notorious for making infections more virulent?
The capsule acts like camouflage for the immune system by covering the antigen's on the surface of the bacterium.
What part of the cell is a fluid mosaic?
The cell membrane is fluid mosaic lipid bilayer with PROTEINS. It's 2D; NOT 3D, meaning proteins & things don't "flip", but move side to side on the membrane. It doesn't flip because of the polarity of the membrane.
Is the diversity of the cell walls of Bacteria & Archaea similar or different?
The cells walls of both Bacteria & Archaea are similar in structure. Archaea cells walls tend to be more DIVERSE & more DENSE in their structure.
What is Mycobacteria's "cord factor"?
The cord factor is glycolipid consisting of glucose diasaccharide trehalose which is covalently attached to two mycolic acids (the waxy lipids). Cord factor is required for Mycobacteria's virulence in TUBERCULOSIS.
What makes the corkscrew motion of Spirochaetes advantageous to the bacteria?
The corkscrew motion allows for the spirochaetes to penatrate semi-solid material. This is the case for Syphilis, which can be detrimental to the immune system of an infected individual.
How does Flagella receive its energy for motility?
The energy for movement, the proton motive force, is provided by ATP.
What causes the movement of corkscrew propulsion in Spirochaetes?
The flagellum in spirochaetes are located in the periplasm (axial filament) and do not protrude from the cell, which causes the movement of the flagellum between the outer membrane and the cell cylinder to produces a corkscrew like propulsion through viscous media such as much and sediment.
What is glycan composed of?
The glycan is made of alternating carbohydrate (sugar) units of N-acetylgulcosamine, NAG & N-acetylmuramic acid, NAM. The cross-links are peptides between N-acetylmuramic acids.
What is a consequence of lacking the HAP2 or FliD protein in the flagella?
The lack of the capping protein, FliD or HAP2, causes leakage of monomers into the medium which can cause the lack of motility in flagella.
What is Cytosol?
The liquid portion of the cytoplasm which has an incredibly high protein concentration.
How does Mycoplasma attach to host tissues?
The narrow neck region of Mycoplasma contains the cytoskeleton composed of protein fibers that are used for adhesion to tissues.
What are the usual amino acid peptides that are cross-linked with NAM?
The peptides, amino acids, are typically L-alanine, D-Glutamine, & D-Alanine Peptido = the peptide bridge that cross-link with the strands of the sugars (NAG & NAM)
What substances are included in the Gram positive periplasm? How is the evidence of these substances obtained?
The periplasm may contain proteins & enzymes. Cryo-electron microscopy has some evidence for this space.
What structure does the peptide bridge take?
The structure of the polypeptide cross-bridges may vary but they always have a tetrapeptide sidechain, which consists of 4 amino acids attached to NAMs. The amino acids occur in alternating D and L forms.
What causes movement in Spiroplasma?
The unique cytoskeletal ribbon of 7 paired parallel protein fibers that help it move within the fluid.
What factors are Mycobacteria resistant too?
They are extremely resistant to acid, alkali & dehydration because of the waxy lipid covering the cell wall.
What are Chlorosomes composed of?
They are surround by a non-unit membrane of GALACTOLIPID. They also contain the major light-harvesting PHOTOPIGMENTS.
What are the genetic differences between Archaea & Bacteria?
They both have a 70S ribosome, but with a different shape. Archaea have more complex RNA polymerases than Bacteria, similar to Eucarya.
What is the result of Type IV Pili being extensively mutated or removed from Neisserua gonorrhoeae?
This would make the Neisserua gonorrhoeae bacteria non-pathogenic because the Type IV pili would be unable to attach to the tissue of the upper urinary tract.
What are 4 examples of prokaryotes with intracytoplasmic membranes?
Thylakoid of Cyanbacteria (photosynthetic membranes). Methanotrophs Nitrifiers. Other Phototrophs
What is the function of Mot A & Mot B?
To allow protons to move to make "work" & to create the rotation of the ring.
What 2 serious diseases are caused by Mycobacteria?
Tuberculosis & leprosy!
What type of pili is galactose sensative?
Type P Pili! :)
What are the general appearance of Mycoplasma?
Very small & have a "flask-like" appearance.
What are the characteristics of the flagellar structure of Vibrio cholera?
Vibrio cholera have sheathed flagella, the sheath is LPS (lipopolysaccarchide) & appears to be an extension of the outer membrane. LPS is characteristic of G negative bacteria.
What substances CAN move across the bacterial cell membrane?
Water, gases, & small hydrophobic molecules.
How does Mechanosensitive channels actually perform their function with the cell membrane?
When a risk of sudden influx of water or hypo-osmotic stress threatens the cell to overexpansion & subsequent lysis of the cell, the mechanosensitive channels OPEN, allows internal solutes to rapidly EXIT the cell, thus lowering the internal osmotic pressure.
When is the glycocalyx considered a capsule?
When neat, organized, & tightly bound gelatinous material adhere to the cell wall. This capsule may enable the bacterium to adhere to environmental surfaces and/or resist phagocytic engulfment.
What causes the motion of "tumbling" in flagella?
When the usual counter-clockwise turn of the filament reverses due to the C ring's motor twitch, & causes a tumbling motion to occur.
When is the glycocalyx considered a slime layer?
When unorganized & loosely attached, it is referred to as a slime layer. Extracellular polysaccharides allow cell to attach to surfaces because its usually sticky.
How do the cytoskeleton proteins benefit the prokaryotic cell?
Work with the peptidoglycan to give the cell its shape.
What are the major chemical components of a phosphlipid?
X = serine, ethanolamine, a derivative of glycerol or a carbohydrate derivative Polar head hydrophilic R1 & R2 = 12- 20 carbons per fatty acid insoluble in water hydrophobic
Does both Gram Negative & Gram Positive have a periplasm?
Yes! It was previously believed that Gram Negative was the only one with a periplasmic space, but new evidence indicated Gram Positive contains one too.
Do all cells have a cell membrane?
Yes! Every single friggin one!
