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35 Cards in this Set
- Front
- Back
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prokaryotic cells
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DNA not enclosed in a membrane
One circular chromosome DNA not associated with histones (special proteins) Cell walls of peptidoglycan in domain Bacteria Usually divide by binary fission |
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Eukaryotic cells
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most of the DNA enclosed in a nucleus
DNA complexed with histones cell contains a number of membrane-enclosed organelles including mitochondria, endoplasmic reticulum, Golgi complex, lysosomes and sometimes chloroplasts cell walls simple when present usually divide by mitosis or meiosis these processes involve a spindle of microtubules |
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diplobacilli
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pairs of bacilli
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streptobacilli
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chains of bacilli
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vibrios
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Bacteria with curved rods
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spirochetes
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are helical and flexible and axial filaments, flagella like structures contained within a flexible external sheath
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Glycocalyx
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a viscous gelatinous polymer external to the cell wall and composed of polysaccharide, polypeptide or both. If made of sugars it is called an extracellular polysaccharide (EPS) and helps in attachment.
The glycocalyx of Streptococcus mutans allows these cells to cling to teeth and initiate the formation of dental plaque. |
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Capsule
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an organized glycocalyx that is firmly attached to the cell wall
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slime layer
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unorganized and loosely attached to the cell wall
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Flagella
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filamentous appendages that propel bacteria
Some bacteria have them, some don’t |
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monotrichous
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having a single polar flagellum
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amphitrichous
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having a flagellum or flagella at both ends of the cell
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lophotrichous
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- having 2 or more flagella at one end or both ends
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peritrichous
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having flagella distributed over the entire cell
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H antigens
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Flagella proteins are
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Axial filaments
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are found in spirochetes
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fimbriae
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(singular - fimbria) - hairlike appendages, shorter and straighter than flagella, for attachment; can occur at poles of bacteria or can be evenly distributed
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Pili
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(singular - pilus) - hollow; grab cells in preparation for transfer of DNA from one cell to another (conjugation) - sex pilus. Facilitate transfer of DNA from one cell to another
Gliding motility Twitching motility Grappling hook model Pseudomonas aeruginosa Neisseria gonorrhoeae Some strains of Escherichia coli |
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Peptidoglycan
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Polymer of disaccharide:
N-acetylglucosamine (NAG) N-acetylmuramic acid (NAM) |
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Gram-Positive Cell Walls
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Teichoic acids
Lipoteichoic acid links to plasma membrane Wall teichoic acid links to peptidoglycan |
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Teichoic acids
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are polymers of glycerol phosphate or ribitol phosphate liked via phosphodiester bonds. Above is teichoic acid from Micrococcaceae
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Gram-Negative Outer Membrane
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Lipopolysaccharides, lipoproteins, phospholipids
Forms the periplasm between the outer membrane and the plasma membrane. Protection from phagocytes, complement, and antibiotics O polysaccharide antigen, e.g., E. coli O157:H7 Lipid A is an endotoxin Porins (proteins) form channels through membrane |
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lipid A - endotoxin
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that is toxic in the bloodstream; can cause a fever and shock that is often deadly
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Acid-fast cell walls
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Like gram-positive
Waxy lipid (mycolic acid) bound to peptidoglycan Mycobacterium Nocardia |
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Mycoplasmas
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Lack cell walls
Sterols in plasma membrane |
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Fluid Mosaic Model
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Membrane is as viscous as olive oil
Proteins move to function Phospholipids rotate and move laterally |
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Photosynthetic pigments
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on foldings called chromatophores or thylakoids
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Aquaporins
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(water channels)
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Group translocation
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Requires a transporter protein and PEP
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group translocation
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a process found only in prokaryotes
the substance is altered as it is transported across the membrane. For instance glucose is phosphorylated. |
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plasmids
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small circular double stranded DNA molecules; may also be attached to plasma membrane; contain 5-100 genes;self replicating (must have an origin of replication); not crucial to survival; may be gained or lost; may carry genes for toxins, antimicrobial resistance, capsules, tolerance to heavy metals
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Inclusions
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usually reserve deposits
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metachromatic granules
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reserve of inorganic phosphate - volutin; sometimes stain red with methylene blue; found in algae, fungi and protozoa as well as in bacteria; characteristic of Corynebacterium diphtheriae
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polysaccharide granules
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consist of glycogen or starch; stain reddish brown or blue with iodine
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lipid inclusions
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appear in Mycobacterium, Bacillus, Azotobacter, Spirillum and others; a common lipid unique to bacteria is poly--hydroxybutyric acid; stains with Sudan dyes
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