Microbial Cell Structure

1
Microbial Cell Structure
A. Features Common to All Cell TypesB.
Prokaryotic CellsC. Eukaryotic CellsD. Viruses

• Features common to all cell types
• Prokaryotic cells
• General features
• Prokaryotic Cell Structures
• Eukaryotic cells
• General Features
• Eukaryotic Cell Structures
• Viruses

Updated Jan 23, 2007
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A. Features common to all cell types
A. Features Common to All Cell Types B.
Prokaryotic CellsC. Eukaryotic CellsD. Viruses

• Bounded by a plasma membrane
• Contain cytoplasm
• Utilize energy and raw materials through
  metabolism
• Have both DNA and RNA
• Reproduce by cell division processes

3
B. Prokaryotic Cells
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• General Features
• Have no (or few) internal membranes
• Many processes that are associated with
  organelles in eukaryotes (e.g. Respiration,
  photosynthesis) are mediated by specialized
  regions of the plasma membrane in prokaryotes

4
B. Prokaryotic Cells
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• General Features (cont.)
• There is no membrane-bound nucleus in
  prokaryotes. Instead the DNA is located within a
  specialized region of the cytoplasm of the cell
  called the nucleoid region. There is no nuclear
  membrane surrounding the nucleoid.
• Includes the bacteria archaeathe terms
  prokaryotic cell and bacterial cell often are
  used interchangeably

5
B. Prokaryotic Cells
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• General Features (cont.)
• Shapes Arrangements See shapes handout
• Sizes
• Typically 0.1 - 20 ?m (with some exceptions)
• Typical coccus 1 ?m (e.g. Staphylococcus)
• Typical short rod 1 x 5 ?m (e.g. E. coli)
• Barely within the best resolution of a good
  compound light microscope

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B. Prokaryotic Cells
7
B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Plasma membrane
• Structure
• Phospholipid Bilayer with Associated Proteins
• Cholesterol is absent (except in the mycoplasma
  group)
• Hopanoids are often present
• Some archaea have plasma membranes with unusual
  lipids and monolayer structures
• Functions
• Maintain Cell Integrity
• Regulate Transport
• Specialized Functions in Bacteria

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Plasma membrane (cont.)
• Internal membranes
• Mesosomes
• Respiratory and Photosynthetic folds

9
B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• The cytoplasmic matrix
• Composition
• Viscous aqueous suspension of proteins, nucleic
  acid, dissolved organic compounds, mineral salts
• Network of protein fibers similar to the
  eukaryotic cytoskeleton

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Ribosomes
• Sites of protein synthesis
• Typically several thousand ribosomes per
  bacterial cell, depending on the state of its
  metabolic activity
• Smaller than eukaryotic ribosomes

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Cytoplasmic inclusions
• Glycogen Granules
• Poly-?-hydroxybutyrate granules
• Lipid droplets
• Gas vacuoles
• Metachromatic granules(Phosphate crystals or
  volutin granules)
• Sulfur Granules

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Nucleoid
• Chromosomal DNA
• Typically, one chromosome per bacterial cell
• Consists of double-stranded, circular DNA
• A few recently discovered groups have gt1
  chromosome per cell and linear chromosomes
• Plasmid DNA
• R-Plasmids
• F-Plasmids

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Prokaryotic cell walls
• Gram Staining
• Method developed by Gram in 1888
• Gram-positive cells stain purpleGram-negative
  cells stain pink
• Later, it was discovered that the major factor
  determining Gram reactions is the bacterial cell
  wall structure
• Gram-positive Gram-negative These terms
  can mean eitherStaining results, or Types of
  cell wall structure

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Prokaryotic cell walls (cont.)
• Peptidoglycan Structure
• Composition
• A Polysaccharide
• Composed of alternating units ofN-acetylglucosami
  ne (NAG) andN-acetylmuramic acid (NAM)

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Prokaryotic cell walls (cont)
• Peptidoglycan Structure (cont)
• Peptide crosslinking between NAM units
• Tetrapeptide or pentapeptide chains attached to
  NAM may crosslink adjacent PG strands
• This gives PG a net-like or mesh-like structure.
• Indirect crosslinking
• Found in Gram-positive bacteria
• TP chains of adjacent PG strands are linked by
  pentapeptide chains
• Direct crosslinking
• Found in both Gm and Gm - bacteria
• TP chains are directly attached to each other

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Prokaryotic cell walls (cont.)
• Gram-positive Cell Wall
• Thick layer of Peptidoglycan
• 20-80 nm in thickness
• Extensively crosslinked, both with indirect
  direct links
• Teichoic Acids
• Polymers of glycerol or ribitol
• Inserted into the PG layer
• Sometimes attached to plasma membrane lipids
• Periplasmic Space
• Space between the PG layer and the plasma
  membrane
• Much smaller than in gram negative bacteria --
  significance questioned

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Prokaryotic cell walls
• Gram-negative Cell Walls
• Outer Membrane
• 7 - 8 nm in thickness
• Bilayer of lipopolysaccharide and phospholipid,
  with outer membrane proteins
• Lipopolysaccharide contains Lipid A A dimer
  of glucosamine with 6 fatty chains Core
  Polysaccharide About 10 monosaccharide units
  O-side chain (O antigen)
• Lipid A is the bacterial endotoxin triggers
  inflammatory effects and hemorrhaging
• Outer Membrane ProteinsPorin Protein 3 porin
  molecules form a channel for transport/diffusion

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Prokaryotic cell walls (cont.)
• Gram-negative Cell Walls (cont.)
• Peptidoglycan Layer
• Thinner than gm positive
• 1 - 3 nm thick
• Less extensively crosslinked
• Anchored to outer membrane via Braun's
  lipoprotein
• Periplasmic Space
• Fluid or gel-filled space
• Much larger in Gm negative cells possibly 20 -
  40 of cell volume
• Periplasmic proteinsHydrolytic enzymes
  Transport proteins

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Prokaryotic cell walls (cont.)
• Variations on Cell Wall Architecture
• Acid-fast Cell Walls
• Many genera in the High GC gram-positive
  bacterial group contain mycolic acids, embedded
  in the peptidoglycan
• Mycolic acids are a class of waxy, extremely
  hydrophobic lipids
• Certain genera contain very large amounts of this
  lipid, and are difficult to gram stain
• These genera may be identified by the acid-fast
  staining technique
• Includes Mycobacterium and Nocardia

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Prokaryotic cell walls (cont.)
• Variations on Cell Wall Architecture (cont.)
• Mycoplasmas
• Bacteria that are naturally have no cell walls
• Includes Mycoplasma and Ureaplasma
• Archaea
• Have archaea cell walls with no peptidoglycan
• Many have cell walls containing pseudomurein, a
  polysaccharide similar to peptidoglycan but
  containing N-acetylglucosamine and
  N-acetyltalosaminuronic acid

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Capsules, slime layers, and S-layers
• Species and strain specific
• Structure of capsules slime layers
• Polysaccharide or polypeptide layer outside cell
  wall
• May be tightly or loosely bound
• Detected by negative staining techniques
• Structure of S-layers
• Found on surfaces of some bacteria and archaea
• Protein layer on exterior of cell
• Regular floor tile pattern
• Function not clear -- Stability?

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Capsules, slime layers, and S-layers (cont.)
• Functions of capsules slime layers
• Attachment
• Resistance to desiccation
• Nutrient Storage
• Evasion of phagocytosis
• e.g. in Streptococcus pneumoniae
• S strain is encapsulated virulent
• R strain is non-encapsulated non-virulent

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Fimbriae and Pili
• Short, hair-like filaments of protein on certain
  bacterial cells
• Believed to function in attachment
• In a few species, specialized pili (sex pili,
  encoded by genes on the F plasmid) enable the
  transfer of DNA from one cell to another
  (conjugation)

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Bacterial flagella and motility
• Function
• MotilityAlmost all motile bacteria are motile by
  means of flagella
• Motile vs. nonmotile bacteria
• Detected by flagella staining or by motility agar
• Different species have different flagella
  arrangements
• Structure
• FilamentComposed of the protein flagellin
• Hook Rotor AssemblyPermits rotational
  "spinning" movement

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Bacterial flagella and motility (cont.)
• Mechanism of Motility
• Run and Tumble Movementcontrolled by the
  direction of the flagellar spin
• Counterclockwise spin Straight RunClockwise
  spin Random Tumble

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Bacterial flagella and motility (cont.)
• Chemotaxis
• Response to the concentration of chemical
  attractants and repellants
• As a bacterium approaches an attractantthe
  lengths of the straight runs increase
• As a bacterium approaches a repellantthe
  lengths of the straight runs decrease
• Mechanism of chemotaxisStimulation of
  chemotactic receptors in the PM this triggers a
  cascade of enzymatic activity that alters the
  timer setting of the flagella rotors

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Bacterial spores
• Function
• To permit the organism to survive during
  conditions of desiccation, nutrient depletion,
  and waste buildup
• Bacterial spores are NOT a reproductive
  structure, like plant or fungal spores
• Occurrence
• Produced by very few genera of bacteria
• Major examplesBacillus Clostridium

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Bacterial spores (cont.)
• Significance in Medicine Industry
• Spores are resistant to killing
• Cannot be killed by moist heat at 100C (boiling)
  
• Killing spores by moist heat requires heating to
  120C for 15-20 min (autoclaving or pressure
  cooking)

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Bacterial spores (cont.)
• Sporulation
• The process of spore formation
• Governed by genetic mechanism
• A copy of the bacterial chromosome is surrounded
  by a thick, durable spore coat
• This forms an endospore within a vegetative cell
• When the vegetative cell dies and ruptures, the
  free spore is released

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B. 2. Prokaryotic Cell Structures
A. Features Common to All Cell TypesB.
Prokaryotic Cells 1. General Features 2.
Prokaryotic Cell Structures a. Plasma
membrane b. The cytoplasmic matrix c.
Ribosomes d. Cytoplasmic inclusions e. The
nucleoid f. Prokaryotic cell walls g.
Capsules, slime layers, and S-layers h.
Fimbriae and pili i. Bacterial flagella and
motility j. Bacterial sporesC. Eukaryotic
CellsD. Viruses

• Bacterial spores (cont.)
• Spore Germination
• When a spore encounters favorable growth
  conditions
• The spore coat ruptures and a new vegetative cell
  is formed

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C. Eukaryotic Cells
A. Features Common to All Cell Types B.
Prokaryotic CellsC. Eukaryotic Cells 1. General
Features 2. Eukaryotic cell structures a.
Nucleus b. Ribosomes c. Cytomembrane
system d. Mitochondria e. Chloroplasts f.
Cytoskeleton g. Vacuoles h. Peroxisomes D.
Viruses

• General Features
• Have complex internal membrane
  system      compartmentalization      membrane-e
  nclosed organelles
• DNA is enclosed in a membrane-bound nucleus
• Includes animal plant cells, fungi, protists
  (protozoa algae)

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C. 2. Eukaryotic Cell Structures
A. Features Common to All Cell Types B.
Prokaryotic CellsC. Eukaryotic Cells 1. General
Features 2. Eukaryotic cell structures a.
Nucleus b. Ribosomes c. Cytomembrane
system d. Mitochondria e. Chloroplasts f.
Cytoskeleton g. Vacuoles h. Peroxisomes D.
Viruses

• Eukaryotic Cell Structures
• Nucleus
• Location of the cells DNA
• Major processes
• DNA replication
• DNA expression (transcription)

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C. 2. Eukaryotic Cell Structures
A. Features Common to All Cell Types B.
Prokaryotic CellsC. Eukaryotic Cells 1. General
Features 2. Eukaryotic cell structures a.
Nucleus b. Ribosomes c. Cytomembrane
system d. Mitochondria e. Chloroplasts f.
Cytoskeleton g. Vacuoles h. Peroxisomes D.
Viruses

• Ribosomes
• Thousands are located suspended in the cytoplasm
  and attached to the rough endoplasmic reticulum
• Major process
• Protein synthesis (translation)
• Ribosomes in the eukaryotic cytoplasm are larger
  than prokaryotic ribosomes
• Ribosomes are also found within mitochondria and
  chloroplasts the ribosomes of these organelles
  are very similar in structure size to
  prokaryotic ribosomes

38
C. 2. Eukaryotic Cell Structures
A. Features Common to All Cell Types B.
Prokaryotic CellsC. Eukaryotic Cells 1. General
Features 2. Eukaryotic cell structures a.
Nucleus b. Ribosomes c. Cytomembrane
system d. Mitochondria e. Chloroplasts f.
Cytoskeleton g. Vacuoles h. Peroxisomes D.
Viruses

• Cytomembrane system
• Folded sacks of membranes within the cytoplasm
• Carry out processing and export of the cells
  proteins
• Major components
• Endoplasmic reticulum (rough and smooth)
• Golgi apparatus
• Transport vesicles
• Lysosomes

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C. 2. Eukaryotic Cell Structures
A. Features Common to All Cell Types B.
Prokaryotic CellsC. Eukaryotic Cells 1. General
Features 2. Eukaryotic cell structures a.
Nucleus b. Ribosomes c. Cytomembrane
system d. Mitochondria e. Chloroplasts f.
Cytoskeleton g. Vacuoles h. Peroxisomes D.
Viruses

• Mitochondria
• Located in the cells cytoplasm
• Major process cellular respiration
• The mitochondria oxidize nutrient molecules with
  the help of oxygen
• Some of the energy is conserved in the form of
  chemical energy (energy-containing chemical
  compounds) that can be used for biological
  processes
• Evolved from bacteria by a process called
  endosymbiosis

40
C. 2. Eukaryotic Cell Structures
A. Features Common to All Cell Types B.
Prokaryotic CellsC. Eukaryotic Cells 1. General
Features 2. Eukaryotic cell structures a.
Nucleus b. Ribosomes c. Cytomembrane
system d. Mitochondria e. Chloroplasts f.
Cytoskeleton g. Vacuoles h. Peroxisomes D.
Viruses

• Chloroplasts
• Located in the cytoplasm of plant cells, algae
  cells, and certain protozoan cells
• Major process photosynthesis
• Using the energy from light, CO2 is converted
  into carbohydrates such as glucose
• Evolved from bacteria by endosymbiosis

41
C. 2. Eukaryotic Cell Structures
A. Features Common to All Cell Types B.
Prokaryotic CellsC. Eukaryotic Cells 1. General
Features 2. Eukaryotic cell structures a.
Nucleus b. Ribosomes c. Cytomembrane
system d. Mitochondria e. Chloroplasts f.
Cytoskeleton g. Vacuoles h. Peroxisomes D.
Viruses

• Cytoskeleton
• Microfilaments
• Microtubules
• Intermediate filaments
• Vacuoles
• Peroxisomes

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D. Viruses
A. Features Common to All Cell TypesB.
Prokaryotic CellsC. Eukaryotic CellsD. Viruses

• Structure of a Virus Particle
• Noncellular Biological Entity
• Contains either DNA or RNA (not both)
• Nucleic Acid is surrounded or coated by a protein
  shell (capsid)
• Some viruses possess a membrane-like envelope
  surrounding the particle

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D. Viruses
A. Features Common to All Cell TypesB.
Prokaryotic CellsC. Eukaryotic CellsD. Viruses

• Viral Replication
• No independent metabolism or replication
• Replicate only inside an infected host cell
• Do not replicate via a process of cell division
• Replicate via a process of
• Attachment and Penetration
• Disassembly (uncoating)
• Synthesis of Viral Protein and Nucleic Acid
• Reassembly of new viral particles
• Release of new viral particles