BACTERIAL MORPHOLOGY BACTERIAL MORPHOLOGY CON’T Plasma CON’T Plasma

(cytoplasmic) membrane(cytoplasmic) membrane

Phospholipid Phospholipid bilayer (Self-bilayer (Self-

assembly)assembly)Two fatty acid tails Two fatty acid tails (hydrophobic)(hydrophobic)

Glycerol-Phosphate Glycerol-Phosphate head head (hydrophilic)(hydrophilic)

Fatty acids(hydrophobic)

Glycerol and phosphate

(hydrophilic)

Phospholipid arrangement in water

Phospholipid self-arrangement

ProteinsProteins•Integral proteinsIntegral proteins

–TransportTransport•Peripheral proteinsPeripheral proteins

–Enzymes Enzymes

Integral protein

Peripheral protein

Plasma membrane Plasma membrane functions functions (BET)(BET)

•BarrierBarrier•Energy productionEnergy production•TransportTransport

Plasma membranePlasma membrane• Target for chemotherapy and disinfectionTarget for chemotherapy and disinfection

– Damage to the membrane by alcohols, quaternary ammonium (detergents) and Damage to the membrane by alcohols, quaternary ammonium (detergents) and polymyxin antibiotics causes leakage of cell contents.polymyxin antibiotics causes leakage of cell contents.•Disruption of phospholipidsDisruption of phospholipids•Selective permeability allows passage of some moleculesSelective permeability allows passage of some molecules

• Enzymes for ATP productionEnzymes for ATP production• Photosynthetic pigments on foldings called chromatophores or thylakoidsPhotosynthetic pigments on foldings called chromatophores or thylakoids

Transport across Transport across membranesmembranes• Simple diffusion:Simple diffusion: Movement of a Movement of a

solute from an area of high solute from an area of high concentration to an area of low concentration to an area of low concentration (often known as concentration (often known as passive transport)passive transport)

• Facilitative diffusion:Facilitative diffusion: Solute Solute combines with a transporter protein combines with a transporter protein in the membranein the membrane

Transport across Transport across membranes membranes

•Active (requires energy, Active (requires energy, usually from lower to usually from lower to higher concentration)higher concentration)

Passive transport across Passive transport across membranesmembranes

•Simple diffusionSimple diffusion•Facilitated diffusion Facilitated diffusion

(permeases)(permeases)•OsmosisOsmosis

Higherconcentration

Lowerconcentration

Facilitated diffusion No energy used !!

Osmosis Osmosis

Sugar or salt molecules(solute)

Semi-permeable membrane (only water flows)

• Liquids flow towards higher solute Liquids flow towards higher solute concentration (lower liquid concentration)concentration (lower liquid concentration)

Active transport across membranesActive transport across membranes • Group translocation Group translocation

–Substance is altered during transport Substance is altered during transport (metabolism-glucose-6-PO(metabolism-glucose-6-PO33) sugars are ) sugars are phosphorylatedphosphorylated

• Carrier proteinsCarrier proteins–Similar to facilitated diffusion, but needs energySimilar to facilitated diffusion, but needs energy

• Group translocation of substances requires a Group translocation of substances requires a transporter protein and PEP transporter protein and PEP (phosphoenolpyruvate)(phosphoenolpyruvate)

• Active transport of substances requires a Active transport of substances requires a transporter protein and ATPtransporter protein and ATP

Energy is used!

Higherconcentration

Lowerconcentration

Group translocation GlucosePhosphate

phosphoenolpyruvate

Microbial Nutrition Acquisition

Cytoplasm contentsCytoplasm contents– Water, proteins, Water, proteins,

carbohydrates, carbohydrates, lipids, inorganic lipids, inorganic ions, DNA, RNA and ions, DNA, RNA and inclusionsinclusions

Nuclear areaNuclear area

•No nuclear No nuclear membranemembrane

•ChromosomeChromosome•Plasmid Plasmid

Bacterial chromosome

• One only• double stranded (ds)

DNA• Attached to plasma

membrane

Bacterial plasmid

• Extrachromosomal genetic material

• Replicate independently• Not crucial for survival

(resistance, enzymes, etc)

RibosomesRibosomes• Protein synthesisProtein synthesis• Two subunits 30 and Two subunits 30 and

50 S = 70 S (rRNA)50 S = 70 S (rRNA)• Target for antibiotic Target for antibiotic

actionaction

InclusionsInclusions•Reserve depositsReserve deposits

–lipids, sulfur, carboxysomeslipids, sulfur, carboxysomes–Metachromatic granulesMetachromatic granules–Polysaccharide granulesPolysaccharide granules–GasGas

Inclusions

EndosporesEndospores– Only Gram-positivesOnly Gram-positives

•BacillusBacillus spp. spp.•ClostridiumClostridium spp. spp.

– Highly resistantHighly resistant– Spore coat has a form of Spore coat has a form of

dipicolinic acid and Cadipicolinic acid and Ca+ +

ions in itions in it

Spores

The eucaryotic cellThe eucaryotic cell• AlgaeAlgae• ProtozoaProtozoa• PlantsPlants• AnimalsAnimals

The eucaryotic cell The eucaryotic cell (cont.(cont.))•Larger and more complex Larger and more complex

than procaryotesthan procaryotes•10 to 100 10 to 100 mm•Membrane-bounded Membrane-bounded

organellesorganelles

Flagella and CiliaFlagella and Cilia

• LocomotionLocomotion• Flagella, few and Flagella, few and

longlong• Cilia, numerous Cilia, numerous

and shortand short

Movement of eukaryotic Movement of eukaryotic flagella and ciliaflagella and cilia

• Respiratory systemRespiratory system• Digestive systemDigestive system• LocomotionLocomotion

Cell wall of eucaryotesCell wall of eucaryotes• Not present in all eucaryotes Not present in all eucaryotes

(alga, plants, some fungi)(alga, plants, some fungi)• No peptidoglycanNo peptidoglycan• Simpler than procaryotesSimpler than procaryotes

Cell wall of eucaryotes (Cell wall of eucaryotes (cont.cont.))• CelluloseCellulose

–Glucose polymerGlucose polymer• Chitin (most fungi, some Chitin (most fungi, some

protozoans)protozoans)–N-acetylglucosamine N-acetylglucosamine

polymerpolymer

Cell wall of eucaryotes Cell wall of eucaryotes ((cont.cont.))

•Polysaccharides (yeast)Polysaccharides (yeast)–GlucanGlucan–MannanMannan

Glycocalyx functionsGlycocalyx functions•Strengthens the cell Strengthens the cell

surfacesurface•Helps attach cells Helps attach cells

togethertogether•Cell to cell recognitionCell to cell recognition•Sticky carbohydratesSticky carbohydrates

Eucaryotes plasma Eucaryotes plasma (cytoplasmic) membrane(cytoplasmic) membrane•Similar to procaryotesSimilar to procaryotes

–Receptor sites Receptor sites (carbohydrates) cell to cell (carbohydrates) cell to cell recognitionrecognition

Eucaryotes plasma Eucaryotes plasma (cytoplasmic) membrane (cytoplasmic) membrane (cont.)(cont.)

–Attachment sites for Attachment sites for bacteriabacteria

–Sterols (rigidity)Sterols (rigidity)–transport (passive and transport (passive and active)active)

Eucaryotes passive Eucaryotes passive transporttransport

•DiffusionDiffusion•Facilitated diffusionFacilitated diffusion•OsmosisOsmosis

Eucaryotes active transport Eucaryotes active transport (endocytosis)(endocytosis)

•Phagocytosis Phagocytosis (macrophages –cells are (macrophages –cells are “eating”)“eating”)

•Pinocytosis (extracellular Pinocytosis (extracellular fluid into the cell—cells are fluid into the cell—cells are “drinking”)“drinking”)

CytoplasmCytoplasm•CytoskeletonCytoskeleton

–MicrofilamentsMicrofilaments–Intermediate filamentsIntermediate filaments–MicrotubulesMicrotubules

Cytoplasm (Cytoplasm (cont.cont.))•Cytoskeleton functionsCytoskeleton functions

–ShapeShape–Movement Movement

•Entire cellEntire cell•Substances within the Substances within the cellcell

NucleusNucleus•Spherical to ovalSpherical to oval•Contains DNA Contains DNA •combined with histones combined with histones •and nonhistonesand nonhistones

Nucleus (Nucleus (cont.cont.))•Chromatin (threadlike)Chromatin (threadlike)

–Non-reproducing cellsNon-reproducing cells•Chromosomes (rodlike Chromosomes (rodlike

structure)structure)–Reproducing cellsReproducing cells

Endoplasmic reticulum (ER)Endoplasmic reticulum (ER)• Network of sacsNetwork of sacs• Synthesis and storage Synthesis and storage

of lipids and proteinsof lipids and proteins

Endoplasmic reticulum (ER) Endoplasmic reticulum (ER) ((cont.cont.))

• Rough ER Rough ER –numerous ribosomes, protein numerous ribosomes, protein

synthesissynthesis• Smooth ERSmooth ER

–Lipid synthesis Lipid synthesis

Golgi ComplexGolgi Complex• Similar to ERSimilar to ER• Receives ER Receives ER

productsproducts– SortsSorts– packagespackages– delivers (secretory delivers (secretory

vesicles)vesicles)

MitochondriaMitochondria

• Double membraneDouble membrane– Multy-folded inner Multy-folded inner

membrane membrane

Mitochondria (Mitochondria (cont.cont.))• Provides a large surface for Provides a large surface for

proteins involved in cellular proteins involved in cellular respiration (ATP synthesis)respiration (ATP synthesis)

• Multiply on their ownMultiply on their own

ChloroplastChloroplast

• Algae and green Algae and green plantsplants

• ChlorophyllChlorophyll• Photosynthesis Photosynthesis

enzymesenzymes• Multiply on their Multiply on their

ownown

LysosomesLysosomes

• Derived from Golgi Derived from Golgi complexcomplex

• Free spheres in Free spheres in cytoplasmcytoplasm

• Contain powerful Contain powerful digestive enzymesdigestive enzymes

• Numerous in white Numerous in white blood cellsblood cells

VacuolesVacuoles• Storage of nutrientsStorage of nutrients• Metabolic wastesMetabolic wastes• WaterWater