Prokaryotes (Pre Nucleus)

 -Bacteria & Archaea

-DNA NOT enclosed within membraine

-Singular circular arrangment

-DNA is NOT associated w/Histones-has other proteins

-LACK membrane enclosed organelles

-Cell walls: PEPTIDOGLYCAN

-BINARY FISSION reproduction

-Very small: 1-10 microns

-Psuedomurein cell walls in ARCHAEA

Eukaryote

-fungi, protista, animalia, plantae

-DNA in NUCLEUS, NUCLEAR membrane

-DNA associated w/HISTONES & nonhistones

-MEMbrane enclosed organelles: mitochondria, ER, golgi, lysosome, some chloroplasts

-Polysachharide cell walls if present

-MITOTIC spindle reprod.= MITOSIS

-Very big: 10-1000 microns

• Bacillis  ( ROD shaped)
• Coccus (spherical)
• Spiral

1. Spirillum
2. Vibrio
3. Spirochete

Cocci Arrangments

Diplococci:

Streptococci:

Tetrads:

Sarcinae:

Staphylococci:

-cocci that remain in pairs

-divide & remain attatched in chainlike

-divide in 2 planes & remain in groups of 4

-divide in 3 planes & cubelike grps of 8

-grape like clusters

Bacilli Arrangments

appear as single rods, long twisted chains

less grouping then cocci

1) Diplobaccili

2)Streptobacili

3)Coccobacilli

1) appear in pairs

2) CHAINS

3)oval and look just like cocci

SPiral

-have one or more twists, never straight

1) Vibrios

2) Spirilla

3) spirochetes

1) curved rods

2) helical shape- use FLAGELLA to move

3) helical & flexible- use AXIAL FILAMENTS to move

MONOMORPHIC

Pleomorphic

Bacteria is determined by heredity

= maintain a single shape

= can have many shapes

- usually .2-1.0 microns x 2.8 microns?

text says .2-2.0 microns in diamter

2-8 microns in length

Glycocalyx (sugar coat)

(prokaryotes secrete this on their surface)

Capsule: if the substance is organized and FIRMILY attatched to cell wall. Can be determined by NEGATIVE STAINING

-OUtside cell wall

-STICKY

-Capsule: neatly organized

-SLIME LAYER: unorganized and loose

-Extracellular polysaccharide allows cells to ATTACH

-Capsules prevent phagocytosis

-VERY important in BIOFILMS

Flagella of Prokaryote

-Prokaryotic cells have this

Gram (-) has how many rings?

Gram (+) has how many rings?

-Outside cell wall

-made of chains of Flagellin

-Attatched to a protein HOOk

-Anchored to wall & membrane by basal body

-Helicobacter pylori- stomach ulcers

(-)2 pairs

(+) 1 -only inner ring

Spirochetes move by

1) axial filaments

best known for Treponema pallidum (syphillis)

Borrelia burgdorferi (lyme diseasea)

- Endoflagella

-bundles of fibrils that arise at end of cell beneath outer sheath

-Rotation causes entire bacterium to move forward in corkscrew motion

- motion allows it to go thru mucus & gain acces to hosts blood and lymph systems thru tissues and membranes

Fimbriae & Pilli

-gram negative bacteria

-shorter, thinner & straighter than FLagella

-used for attatchment and transfer of DNA rather then movement

Pilin= structure consisting of protein, arranged in helical around central core- divided into two types. FImbriae & pilli

Fimbriae- used for attatchment

-form biofilms

-help bacteria stick

Pilli- not MAIN role of attcmt but CONJUGATION

-transfer DNA from one cell to another

FImbria absent, then no disease can happen bc it cant colonize

*help colonize mucous membranes (ex: gonorea)

Bacterial cell wall

- may allow certain Bacterial to cause disease

- semi rigid structure

-respoonsible for SHAPE

-surrounds plasma membrane & protects cell from outside envt

-prevents osmotic lysis

-PEPTIDOGLYCAN walls in bacteria= site of action for antibiotics

-alternating NAM & NAG molecules linked to form carbohydrate "backbone"

- Adjacent polypeptides are linked

-4 amino acids attatched to NAMs in backbone

-Penicllin interfers w/final linking  of the peptidoglycan rows by peptide cross bridges

-the wall weakens bc of this and cell undergoes lysis

- MANY thick layers of peptidoglycan

-contain teichoic acids

-1 or very few layers of peptidoglycan & OUTer membrane

-peptidoglycan is bonded to LIPOPROTEINS in outer membrane

-NO teichoic acids

-more suseptible to mechanical breakage

-outer mem: LIPOpolysach., lipoproteins & phospholipids

strong negative charge & barrier to antiobiotics

-has porins

+

-THICk peptidoglycan

-Teichoic acids

-

=Thin pep.

-Outer membrane

-periplasmic space

GRam stain Mechanism

-mechanism is based on differences in structures of cell wall

1)Crystal Violet- iodine crystals form in cell, dye enters cytoplams of both + and - gram

-the iodine (the mordant) forms large crystals

2)Alcohol then dehydrates the peptidoglycan of gram+ to make more impermeable to crystal-violet iodine

-on gram(-) it desolves outer membrane of thin pep. layer

-

Gram (+)

-alcohol dehydrates peptidoglycan

-CV-I crystals dont leave

-Pink/Red

Gram (-)

-Alcohol dissolves outer membrane & leaves holes in thin peptidoglycan

-CV-I washes OUT

Purple stain

Atypical Cell Walls

-have ACID-FAST cell walls

-similar to gram (+)

-WAXY LIPID (mycolic acid) bound to peptidoglycan

-*Mycobacterium

-* Nocardia

     -*Cant be gram stained

-can b sstained w Carbolfuch. & heated

-retain RED color

-if mycolic acid layer is removed from stain wall of acid fast bacteria then it will stain GRAM+ in gram stain

Atypical Cell Walls

1) Mycoplasmas

2) Archaea

1) Lack cell walls

-Sterols in plasma membrane (cholestorol in cell wall)

-Pnemonia is wall less )fried egg appearance)

2) Wall LESS

-or walls of PSEUDOmurein

-(lack NAM and D amino acids)

-Lysozyme digests disaccharide in peptidoglycan

      -active in most  gram + bacteria (makes them vulnerable to lysis)

       -tears, mucus & saliva

-Penicillin INHIBITS peptide bridges in peptidoglycan

Plasma Membrane

-bilayer, selective permeable

-Outer membrane only in Gram (-)

-membrane is as viscous as olive oil

-Proteins move to function

-Phospholipids rotate & move laterlly

In Prokaryotes: made of phospolipids

- less rigid bc lack sterols

-EXCEPT: Mycoplasms

In Eurkaryotes: Carbs, sterols (cholestorl)

Plasma Membrane

-Selectively Permeable

-Enzymes for ?

-Chromatophores or Thylakoids

-important for breakdown of nutrients & production of ATP

- allows ppassage of some molecules

-ATP prduction

-Photosynthetic pigments.Found in infoldings that extend to cytoplasm

POLAR heads: 2 surfaces on lipid bilayer

NONpolar tails: interior of bilayer

Mvemt across Membranes

1) Simple diffusion

2) Faciliative Diffusion

-dont need energy for this

3)Osmosis

4)Osmotic Pressure

1)(perfume) mvmt of SOLUTE from HIGH concentration to LOW conc.

2)Solute combines w/transporter protein in membrane

3) Mvmt of WATER across a selectively permeable membrane from HIGH WATER to LOWER water concentration

-OR from LOW SOLUTE conc. to HIGH solute

4) Pressure needed to stop mvmt of water across membrane

1)Simple Diffusion & Facilited: NO energy required bc of going from HIgh SOLVENT to LOW

2) Osmosis: High SOLVENT to low

1) cells rely on this to transport SMALL molecules like O2, CO2

Mvmt of Materials across Membranes

1) Active Transport

2) Group Translocation

1) Requires a transporter protein & ATP- NEED GLucose

2) Requires a transporter protein & PEP

- Substance INSIDE plasma membrane

-Contains Nuclear Region

The PROKARYOTIC Ribosome

Eukaryotic Ribosome

- Protein synthesis

-70S

-80S