Chapter 4 Part 1 - Prokaryotic Cells

Prokaryotic cell

• unicellular

• lack nucleus and membrane bound organelles

• Include bacteria and archea

Bacterial reproduction

binary fission

Average size of bacteria

.2 - 2 micrometers

bacterial shapes

coccus (spherical)

bacillus (rod)

Spiral or sparila

monomorphic

one shape

pleomorphic

multiple shapes

bacterial arrangements

strepto (chain)

staphylo (cluster)

diplo (two)

Glycocalyx

sugar coat outside of cell wall

• capsule

• slime layer

• extracellular polysaccharide

Capsule

• firmly attached

• evades phagocytosis

Slime layer

• loosely associated

• attachment

Extracellular polysaccharide (EPS)

biofilms

community of bacteria = allows for communication

protects

attachment

Flagella/Archaella

rotate to push the cell (propellec)

Axial filaments

spiral cells - wrap around cell just underneath outer sheath

endoflagellum

spirochete: treponema pallidum, borrelia burdofer

Fimbriae

hair like structures outside of cell

for adherence to surfaces

like velcro

Pili

motility: twitching and gliding

DNA transfer (sex pillus): sexual reproduction, transfer of plasma DNA

Cell wall

structure that surrounds the cell membrane

protects cell from changes in H2O water pressure

bacteria’s cell walls are peptidoglycan

peptidoglycan

sugar-protein polymer

Gram+ have a very thick peptidoglycan layer with no LPS or outermembrane

Gram- bacteria will have a thin peptidoglycan layer with an outermembrane and LPS (lipopolysaccharide)

Gram staining steps

1. Crystal violet

2. iodine

3. decolorie with alcohol

4. safranin as counterstain

purple if +, pink if -

Atypical cell walls

no cell walls - mycoplasma

acid fast cell wall - mycobacterium, not able to be stained

archea-pseudomuerin - no peptidoglycan cell wall

Plasma membrane

phospholipid bilayer

• membrane proteins

• selectively permeable

movement across membrane

high to low concentration in order to reach equilibrium

Concentration gradient

Passive movement

simple diffusion

facilitated diffusion

osmosis

simple diffusion

no energy required

movement down the concentration gradient

facilitated diffusion

transport protein

channel protein

osmosis

Osmosis

movement of water

concentration of SOLUTE is shown NOT WATER so you need to calculate

water follows salt, where there is HIGHER SOLUTE is the direction in which the water will move

Active transport

up concentration gradient

requires energy

cytoplasm contains

water

organic and inorganic molecules

DNA

Ribosomes

Cytoskeleton proteins

inclusion bodies

nucleoid region

area where DNA is located

No walls surrounding → very efficient

circular chromosome

Ribosomes

70s (bacteria)

site of protein synthesis

Inclusions

functional areas inside the cytoplasm

Endospores

gram positive bacteria

resting structure during adverse conditions

all cells have

nucleic acid

ribosomes

plasma membrane

cytoplasm