functional anatomy of prokaryotic cells-sp10
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Functional Anatomy of Prokaryotic CellsTRANSCRIPT
Functional Anatomy of Prokaryotic Cells
Chapter 4
Prokaryotic and Eukaryotic Cells
Prokaryote comes from the Greek words for prenucleus.Eukaryote comes from the Greek words for true nucleus.
Prokaryote
One ci rcular chromosome, not in a membraneNo histonesNo organellesPeptidoglycan cell wallsBinary fission
Eukaryote
Paired chromosomes, in nuclear membrane
Histones presentO rganellesPolysaccharide cell wallsMitosis
Figures 4.1a, 4.2a, 4.2d, 4.4a, 4.4b, 4.4c
Basic Shapes/MorphologyBacillus (rod-shaped)
Coccus (spherical)
SpiralSpirillumVibrioSpirochete
Scientific name: BacillusShape: Bacillus
Unusual Shapes of Bacteria
Hyphal/F ilamentous bacter ia
Figures 4.1a, 4.1d, 4.2b, 4.2c
B A C T E RI A L A RR A N G E M E N T
Pairs: Diplococci, diplobacilli
Chains: Streptococci, streptobacilli
C lusters: Staphylococci
Bacter ial A r rangement
Clusters:
Tetrads
Sarcinae
monomorphic
vs.
pleomorphic
Rhizobium, Corynebacterium
Significance of Size
1. Typical size of prokaryote vs. typical eukaryote
1-2 m vs. 10-100 m 1 m = 10-6 m
2.Epulopiscium sp.
3. Observing a bacter ium vs. a colony
4. Advantage of small size
Figure 4.6
Functional Anatomy of Prokaryotic Cells
A . G lycocalyx
Outside cell wallUsually stickyCompositionTwo types of G lycocalyx:Capsule vs. Slime layer
A . G lycocalyx
Functions of G lycocalyx:Slime layer allows cell to attachCapsules prevent phagocytosis
B . Cell Wall
1. FunctionPrevents osmotic lysis, r igidity, shape
2. Composition and Structure
Peptidoglycan (PG)
Peptidoglycan (PG)
1. Disaccharide polymer (N A G and N A M)2. Tetrapeptide side chains3. Peptide cross br idges
Polymer of disaccharide:N-acetylglucosamine (NAG) N-acetylmuramic acid (NAM)
Figure 4.13a
Peptidoglycan
Two types of cell walls
Differentiation based on amount of PG and other componentsG ram-positive vs. G ram-negative
1) G ram-positive (Gm+) cell walls
a. Thick layers of PGb. Presence of
teichoic acids (A lcohol/Glycerol plus phosphate)-May regulate movement of cations-Provide antigenic variation
2) G ram-negative (Gm ) cell walls
a. Thin layer of PG + outer membrane
b. No teichoic acids
c. Outer membrane: made up ofL ipopolysaccharides (LPS)LPS = O polysaccharide + L ipid A
G ram-negative (Gm ) cell walls
L ipid A is an endotoxinO polysaccharide antigen, e.g., E . coli O157:H7
Thick peptidoglycanTeichoic acids
G ram-positiveCell Wall
Figure 4.13b c
Thin peptidoglycanOuter membrane
G ram-negativeCell Wall
How penicillin affects bacter ial
E ffect on G ram-positive vs. G ram- negative
Atypical Cell Walls
a. Acid Fast cell wallWaxy lipid (Mycolic acid) bound to peptidoglycan in acid-fast cell walls.
MycobacteriumNocardia
Atypical Cell Walls
b. MycoplasmasLack cell wallsSterols in plasma membrane
c. A rchaeaWalls of pseudomurein (lack N A M and D-amino acids)
Figure 4.14a
C . The Plasma Membrane or Cytoplasmic membrane
C . The Plasma Membrane
1. Phospholipid bilayer and Proteins
2. F luid Mosaic Model
C . The Plasma Membrane
3. Functions of plasma membraneSelective permeability allows passage of some moleculesEnzymes for ATP productionPhotosynthetic pigments Damage to the membrane by alcohols, quaternary ammonium (detergents), and polymyxin antibiotics causes leakage of cell contents
4. Movement Across Plasma Membrane
1. Passive T ransporta. Simple diffusion: C O2, O2b. Facilitated diffusion: G lycerolc. Osmosis: water
2. Active transporta. Active T ransportb. G roup T ranslocation
Figure 4.17a
Passive T ransporta. Simple diffusion:
Movement of a solute from an area of high concentration to an area of low concentration
Figure 4.17b-c
Passive T ransportb. Facilitated diffusion: Solute combines
with a transporter protein in the membrane
Figure 4.18a
Passive T ransportc. Osmosis:
The movement of water across a selectively permeable membrane from an area of high water to an area of lower water concentration
Figure 4.18c e
Osmolarity of the solution outside bacterial cells and its significance
Active transport
a. Active T ransportUsing either PM F or A TP
b. G roup T ranslocation
Endocytosis and Exocytosis????
G roup T ranslocation
D . F lagella
1. Function
2. Made up of 3 partsa. filament: F lagellinb. A ttached to a
protein hook
c. anchored to the wall and membrane through basal body
Flagella proteins are H antigens (e.g., E . coli O157:H7)
a. Monotrichous b. amphitr ichousc. Lophotr ichous d. per itr ichous
3. F lagellar ar rangement on a bacter ial cell surface
4. Run and tumble
5. chemotaxis and phototaxis
6. H elicobacter pylorii
7. other types of bacter ial motility
1. Who has them?
2. F imbriae
3. Pili -Facilitate transfer of DN A from one cell
to another-G liding motility-Twitching motility
E . F imbriae and Pili
No Cytoskeleton
No membrane bound organelles
F . Cytoplasm
1. bacter ial chromosome character isticsNo nuclear membraneNo H istonesCircular DN AHaploid
2. size and packaging: Supercoiling
G . Nucleoid
1. What are they?
2. Advantages to bacter ia
3. Transfer
H . Plasmids
I . Ribosomes
1. Function2. Composition/structure
3. Antibiotic effect on r ibosomes
J. Inclusions/storage granules
1. M etachromatic/volutin/polyphosphate granulesdiagnostic use: Corynebacterium diphtheriae
2. Polysaccharide G ranules
3. L ipid Inclusions PH B:poly- -hydroxy butyric acid
4. Sulfur G ranules
K . Endospores
1. Who produces?
2. N O T reproductive! Resting structures
3. When are they produced?
4. How long can they survive?
Formation of Endospores by Sporulation
Figure 4.21a
5. Structure of a free endopsore (DPA)
6. G ermination
7. Importance of endospores medically and infood processing
8. Destroying endospores
a. John Tyndall and tyndallizationb. autoclave and pressure cooker