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59 Cards in this Set
- Front
- Back
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What are the two major groups of procaryotes?
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Bacteria and Archaea
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What are the three morphologies regarding procaryotes?
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-cocci(coccus)
-bacilli (bacillus) -spirilla (spirillum) |
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What are the different arrangements under cocci?
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-diplococci (pair)
-streptococci (chain) -staphylococci (cluster) -tetrads (square) -sarcinae (cube) |
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What are the different arrangements under bacilli?
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-coccobacilli (very short rod)
-streptobacilli (chain) -vibrios (curved rods) -mycelium (long, multinucleate filaments) |
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How are spirilla and spirochetes different?
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Spirilla are rigid and motile by flagella. Spirochetes are flexible and motile by axial filaments.
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What is pleomorphic?
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organisms that are variable in shape
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What are some examples of pleomorphism?
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-Mycoplasma
-Arthrobacter -Corynebacteria |
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Mycoplasma
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lack a cell wall, cant be treated with antibiotics that change the cell wall
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Arthrobacter
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Rod shaped. When environment is depleated of nutrients it turns into a sphere
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Corynebacteria
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club-shaped
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Bacillus
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the genus Bacillus
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Streptococcus
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the genus Streptococcus
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What is the size of E.coli?
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1X2-4 micrometers
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Procaryotic Cell
Plasma membrane |
Selectively permeable barrier, mechanical boundary fo cell, nutrient and waste transport, location of many metabolic processes (respiration, photosynthesis), detection of environmental cues for chemotaxis
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Procaryotic Cell
Gas Vacuole |
Buoyance for floating in aquatic environments
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Procaryotic Cell
Ribosomes |
Protein Synthesis
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Procaryotic Cell
Inclusion Bodies |
Storage of carbon, phosphate, and other substances
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Procaryotic Cell
Nucleoid |
Localization of genetic material (DNA)
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Procaryotic Cell
Periplasmic space |
Contains hydrolytic enzymes and binding proteins for nutrient processing and uptake
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Procaryotic Cell
Cell wall |
Gives bacteria shape and protection from lysis in dilute solutions
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Procaryotic Cell
Capsules and slime layers |
Resistance of phagocytosis, adherence to surfaces
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Procaryotic Cell
Fimbriae and pili |
Attachment to surfaces, bacterial mating
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Procaryotic Cell
Flagella |
movement
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Procaryotic Cell
Endospore |
survival under harsh environmental conditions
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Describe the procaryotic cell membrane. What are its major components?
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Membranes are requirement for all living organisms.
Plasma membrane encompasses the cytoplasm. Some procaryotes also have internal membrane systems. Very similar to that of a eucaryotes. |
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Plasma Membrane, contains?
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Lipids (form bilayer) and proteins (embedded in or associated with lipids).
Highly organized, asymmetric, flexible, and dynamic. |
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Asymmetry of membrane lipids
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Polar ends; interacts with water; hydrophilic
Nonpolar ends; insolube in water; hydrophobic |
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How does the cell membrane of the Archaea differ from that of the Bacteria?
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Archael membrane is composed of unique lipids and some have monolayer structure instead of bilayer. There are lipid diethers and tetraethers in Archaea.
Ester of glycerol= Bacteria Glycerol ether= Archaea |
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Steroids & Hopanoids
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Bacteria do not synthezie steroids. Some acquire steroids from host. Many bacteria synthesize hopanoids.
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What are the two types of membrane proteins? describe
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-Peripheral proteins. Loosely associated with the membrane and easily removed.
-Integral proteins. Embedded with the membrane and not easily removed (includes e- transport system). |
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What are the major functions of the procaryotic cell membrane?
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-separate cell from environment
-selectively permeable barrier -location of crucial metabolic processes (e- transport system) -detection of & response to chemicals (chemotaxis, quorum sensing) |
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Organelle
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Internal structure formed separately from the cell membrane
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Mesosomes
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-may be invaginations of the plasma membrane. Plays a role in cell wall formation and chromosome replication.
-May be artifacts of chemical fixation process |
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Other Internal Membrane Systems
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-complex in-folding of the plasma membrane
-observed in many photosynthetic bacteria, autotrophs. May be aggregates of spherical vesicles, flattened vesicles, or tubular membranes. Strucutre are NOT organelles. |
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Cytoplasmic Matrix
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Substance between membrane and nucleoid (nuclear membrane). Packed with ribosomes and inclusion bodies. Highly organized with respect to protein location.
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Do procaryotes have a cytoskeleton? Function of cytoskeleton?
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Homologs of all 3 euc. cytoskeleton elements (microfilaments, intermediate filaments, microtubules) recently identified in Bacteria and one in Archaea. Functions include roles in cell division, protein locatization and determination of cell shape.
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What is an inclusion body?
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Granules of organic or inorganic material that are stockpiled by the cell for future use. Some are enclosed by a single-layered membrane.
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Examples of organic inclusion bodies (6)
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1. glycogen
2. poly-B-hydroxybutyrate (PHB) 4 carbons 3. Other polyalkanoates (4-16 Carbons) 4. Cyanophycin granules 5. Carboxysomes (CO2 fixation) 6. Gas Vacuoles |
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Cyanophycin granules
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large polypeptides containing abt equal quantities or arginine and aspartic acid
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Gas vacuoles
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Found in cyanobacteria and some other aquatic procaryotes. Provide buoyancy. Aggregates of hollow cylindrical structures called gas vesicles (protein layer). Use gas vaculos to move to certain area of water to catch certain light wavelength. Fill with gas they rise, release gas they descend.
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Examples of inorganic inclusion bodies (3)
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-Polyphosphate granules. Also called volutin granules and metachromatic granules.
-Sulfur granules -Magnetosomes |
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Procaryotic ribosome
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Complex structure consisting of protein & RNA. Sites of protein synthesis.
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How does the procaryotic ribosome differ from that of a eucaryote?
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Procaryote ribosome is smaller than a eucaryotic ribosome. Pro: 70S Eu: 80S
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S=
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Svedberg unit. Depends on weight, volume and shape.
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Procaryotic Nucleoid
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Irregularly shaped region. Location of chromosome (nucleoid). Not membrane-bound
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Procaryotic "chromosome"
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Closed circular, double-stranded DNA molecule. Looped and coiled extensively. Nucleoid proteins probably aid in folding (nucleoid proteins differ from histones). DNA is attached to the cell membrane at one or more points.
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Unusual nucleoids
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Some procaryotes have >1 chromosome. Some have chromosomes composed of linear double-stranded DNA. A few have membrane-delimited nucleoids.
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What is a plasmid?
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Small, closed circular DNA molecule. Exist and replicate independently of chromosome. Not required. May carry genes that confer selective advantage (drug resistant).
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Curing
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The loss of a plasmid
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How are plasmids classified? Examples?
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Based on mode of existence, spread, and function. F plasmid, R plasmid, col plasmid, virulence plasmid, metabolic plasmid.
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Structure of procaryotic cell wall
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Rigid structure that lies just outside the plasma membrane. Sometimes called the cell envelope.
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Function of procaryotic cell wall.
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Provides shape to cell.
Protects cell from osmotic lysis. May contribute to pathogenicity (involves specific attachment structures, may trigger inflammatory response) May protect cell from toxic substances Very few procaryotes LACK cell walls |
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What two major groups are Bacteria divided into based on the response to Gram-stain procedure?
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-Gram-positive bacteria stain purple
-Gram-negative bacteria stain pink |
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What is staining reaction in a Gram stain due to?
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cell wall structure. Archaea have diff types of cell walls, but Gram stain doesn't correlate well with structure.
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What is the periplasmic space (periplasm)? Where is it located?
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Periplasm is the substance that occupies periplasmic space. Located as gap between plasma membrane and cell wall (gram +) or between plasma membrane and outer membrane (gram -).
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What is an exoenzyme?
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Secreted by gram + bacteria. Preform many of the same functions that periplasmic enzymes do for gram - bacteria.
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Perimplasmic enzymes. Function?
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Found in periplasm of gram - bacteria.
-nutrient acquistion -electron transport -peptidoglycan synthesis -modification of toxic compounds |
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Structure of peptidoglycan?
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In both gram + and gram -. Polysaccharide formed from peptidoglycan subunits. Two alternating sugars form backbone: N-acetylglucosamine and N-acteylmuramic acid.
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Gram + Cell Wall
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Composed primarily of peptidoglycan. May also contain large amounds of teichoic acids. Some have layer of proteins on surface of peptidoglycan.
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