BIOL 237 Chapter 3 Lecture Notes

1. mycoplasmids↔cell wall less bacterias
2. ABC transporters↔carrier protein; primary active transports. used by tonB
3. Cytoskeletal Proteins

1. MreB and Mbl protein↔hoogue of actine,

1. fucntion→helps in maintaining rod shape by localizing peptidoglycan
synthesis.

Why is the MreB not found in cocci shaped bacteria?→because it
1.
maintains rod shape
2. FtsZ↔homolgue of tubuling. forms a ring at the center of the divinging daughter
cells. first bacterial cytoskeletal proteins
3. CreS↔(Crescentin)↔ homologue of lamin and keratin ↔ filament proteins
↔responsible for curve shapes
2. Carl woese↔3 domains of life
3. microbacterium↔a slow growing rod shaped gram positive - actinobacteria

1. actinobacteria↔phylum of gram positive bacteria
2. Cell capsule↔organized, composed of polysaccharides

1. fucntion→prevent phagocytosis
2. cell envelope↔covers the different layers above the cytoplasm as a protective
layer
3.
4. Surface area to volume ratio→small cells have higher surface area to volume.

1. higher surface area to volume ratio means→cells can exchange nutrients faster
per unit of cell volume. thast why smaller cells grow faster. given amount of
resource will support a larger population of smaller cells.
2. a rod with the same volume as a coccus has a higher S/V ratio
3. greater S/V ratio is important so larger prokaryotes have coiled or convoluted
plasma membrane to maximize the S/V ratio for example epulospiscium
fishelsoni




4.

,5. surface area=↔4 pi r2
6. volume=→4/3 pi r3
7. S/V→3/r
8.
2. Bacterial Cell

1. cell envelope includes→plasma membrane and everything covering the plasma
membrane. bacteria cell envelope includes plasma membrane, cell wall and at
least a slime layer or capsuel or S layer. phospholipid has D glycerol instead of L.
2.




3. Plasma membrane↔selectively permiable, metabolic processes, detection of
chemotaxis

1. amphipathic↔phospholipids having hydrophilic and hydrophobic side.
2. 2 types of plasma membrane proteins→peripheral membrane proteins and
integral membrane proteins

peripheral membrane proteins↔can be easily extracted from the
1.
membrane; soluble; 20 to 30% of the membrane protein
2. integral membrane proteins↔not easily extracted from
membranes; insoluble; amphipathic, hydrophobic regins are
burried in the membrane and hydrophilic portion projects in the
membrane surface. eg:transport proteins
2. Microdomains↔regins of the membrane formed by different lipids,

1. flotillins↔protein component of microdomain, integral membrane
proteins that functions to assemble large protein complexes like
secretin systems for transporting molecules out of the cell.

, 2. Growth factors↔nutrients that must be obtained from the environment and cannot
be synthesized. like purines, pyrimidines and vitamins or amino acids.
3. Movement of nutrients accross membrane

1. Passive diffusion→movement down a concentration gradient; requires no
energy; rate and extent depends u=on concentration gradient. gases
diffues, water moves slowly.
2. Membrane transport

1. Facilitated diffusion→uses protein channel or carriers; functions
faster at lower concentration gradient than passive diffusion;
carriers binding can change its shape for release of solute in and
out of membrane.
ex:Aquaporin.




2. Active transport→Carrier protein used; specificity; moves
substance up their concentration gradient.

1. Primary active transport→use primary transporter carrier
proteins; (ABC transporter); also uses a substrate binding
protein to bind the molecule being transported; amino acids
and sugar, ATP hydrolysis ; uniporters