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61 Cards in this Set
- Front
- Back
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Prokaryotic cells |
Domain Bacteria and Archaea Smaller size: high surface, low volume Quick nutrient uptake Allows rapid growth |
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Shapes of prokaryotic cells |
Coccus (spherical) Rod (cylindrical "bacillus") Vibrio Spirilium Spirochete Pleomorphic |
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Division of prokaryotic cells |
Binary fission that forms chains or clusters |
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Chain of prokaryotic cells |
Diplococcus (pair) Streptococcus (chain) |
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Clusters of prokaryotic cells |
Sarcina ("even packets") Staphylococcus ("grape like clusters") |
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Bacillus (rod shaped bacteria) characteristic groupings |
Cocobacillus ("more oval") Bacillus ("rod") Diplobacilli ("2 rods") Streptobacilli ("several rods in a line") |
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Cytoplasmic membrane |
Defines the cell boundary Serves as the crucial permeability barrier between the cell and its external environment |
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Structure of cytoplasmic membrane |
Phospholipid bilayer embedded with proteins Hydrophobic tails face in Hydrophilic tails face out |
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Fluid mosaic model |
Proteins drift laterally |
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Function of proteins in the membrane |
Selective gates for movement of molecules Act as sensors of environmental conditions Receptors |
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Cytoplasmic membrane |
Selectively permeable O2, N2, CO2, H2O and small hydrophobic molecules pass through freely |
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Aquaporin |
Membrane protein specifically for passage of H2O molecules |
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Movement throughout membrane is done through |
Simple diffusion and osmosis |
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Simple diffusion |
Movement of molecules from a region of high concentration to low concentration until equilibrium is reached |
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Osmosis |
Diffusion of water across selectively permeable membrane due to unequal solute concentrations |
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Osmosis solutions |
Hypotonic: less solute, more water Hypertonic: more solute, less water Isotonic: same amount of water/solute |
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Water flows from |
hypotonic to hypertonic |
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Is there water movement between isotonic solutions? |
No |
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Transport systems |
Mechanisms that allow nutrients and other small molecules to enter the cell Proteins move through specific carriers |
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Types of transport |
Facilitated Diffusion Active transport Group translocation |
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Facilitated diffusion |
Transporter allows substance to move from high to low concentration (no energy required) |
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Active transport |
Moves compounds against concentration gradient (requires energy) |
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Group translocation |
Transporter chemically alters the substance as it is transported across the membrane |
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Prokaryote cell wall |
A strong rigid structure that prevents cell from bursting and gives bacteria their characteristics and shapes Composed of peptidoglycan |
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Peptidoglycan
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Only found in Domain Bacteria Protein carbohydrate complex Alternating series of glycan chains between NAM-NAG molecules |
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NAM molecules |
Have tetrapeptide chains of AA's that determine strength of peptidoglycan
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Tetrapeptides in Gram Negative bacteria |
Joined directly |
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Tetrapeptides in Gram Positive bacteria |
Linked indirectly by a peptide interbridge |
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Gram positive cell wall |
Thick layer of peptidoglycan Small substances still pass through Gel-like substance is sandwiched between the cytoplasmic membrane and peptidoglycan layer |
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Gram negative cell wall |
Thin layer of peptidoglycan Outside peptidoglycan layer is a unique outer membrane called lipopolysaccharide (LPS) |
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Lipopolysaccharide (LPS) |
Endotoxin Includes Lipid A: immune sx recognizes as pyrogen (fever causing) Includes O antigen: used to identify strains fo different bacteria |
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What is between the cytoplasmic membrane and outer membrane? |
Periplasmic space = filled with gel like periplasm that is composed of proteins |
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Bactericidal |
Substance that kills bacteria directly, such as penicillin Best used in GP bacteria |
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Bacteriostatic |
Substance that stops bacteria from reproducing Interferes with protein reproduction and DNA replication |
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Lysozome |
Natural form of protection against GP pathogens |
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Mycroplasma |
Flexible bacteria Does not have a rigid cell wall (no peptidoglycan) Cytoplasmic membrane makes it stronger than most bacteria Reistant to penicillin and lysozome |
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Structure outside cell wall |
Has a gel like layer outside cell wall |
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Capsule |
Distinct, gelatinous, protects against phagocytosis, helps evade immune system |
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Slime layer |
Diffuse, irregular, allows attachment to surfaces |
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Most structures are made of what? |
Glycolax (sugar) and some are polypeptides |
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Flagella |
Long protein structures responsible for prokaryotic motility; anchored in the cytoplasmic membrane and cell wall and extend out past surface of cell |
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How do flagella move? |
Spin like propellars |
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Structure of flagella |
Helical structure with hollow core, basal body, hook, filament |
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Characterization of flagella |
Peritrichous (flagella all over surface of cell) Polar Flagellum (single flagellum at the end of cell) Amphitrichious (one at each end of cell) Lophotrichous (tufts at both ends) |
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Chemotaxis |
When motile bacteria sense the presence of cheicals and respond by moving in a certain direction; towards nutrients or away from toxins |
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Aerotaxis |
Towards or away from oxygen
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Magnetotaxis |
Towards or away from magnetic fields |
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Thermotaxis |
Towards or away from heat |
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Phototaxis |
Towards or away from light |
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Pili |
Hair like appendates found on the surface of many bacteria Shorter than flagella Are involved in attachment to surfaces or in DNA exchange Fimbrae resembles fringe Sex pili: bacteria for DNA transfer |
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Do prokaryotic cells have a nucleus? |
No, nucleoid formed by chromosomes |
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Chromosome
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single, double stranded, circular DNA molecule that contains all genetic information required by a cell |
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Plasmid |
Smaller than chromosome No essential genetic information Carries genes of antibiotic resistant genes |
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Ribosomes |
Involved in protein synthesis Facilitate joining of amino acids S unit for size |
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Prokaryotic ribosome size |
70S |
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Cytoskeleton |
Internal protein framework |
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Storage granules |
Accumulation of polymers synthesized from excess nutrients |
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Gas vesicles |
Small rigid protein bound compartments that provide buoyancy |
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Endospores |
Dormant and heat resistant cell Produced by Bacillus and Clostridium Formed by sporulation, triggered by carbon or nitrogen limitation |
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Germination
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Cell is no longer dormant, becomes vegetative |
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Vegetative cell |
Typical multiplying cell |
