MicrobiologyB.E Pruitt & Jane J. Stein

AN INTRODUCTIONEIGHTH EDITION

TORTORA • FUNKE • CASE

Chapter 4, part BFunctional Anatomy of Prokaryotic and

Eukaryotic Cells

• Functions for membranes• Selective permeability allows passage of some

molecules• Movement through the membrane

• Active - requires energy• Passive - no energy involved

• Enzymes for ATP production• Photosynthetic pigments on foldings called

chromatophores or thylakoids

Plasma Membrane

• Damage to the membrane by alcohols, quaternary ammonium (detergents) and polymyxin antibiotics causes leakage of cell contents.

Plasma Membrane

Passive TransportDiffusion and Osmosis

• Simple diffusion: Movement of a solute from an area of high concentration to an area of low concentration.

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

Movement Across Membranes

Passive transport

Movement Across Membranes

Figure 4.17

• Osmosis• Movement of water

across a selectively permeable membrane from an area of high water concentration to an area of lower water.

• Osmotic pressure• The pressure needed to

stop the movement of water across the membrane.

Movement Across Membranes

Figure 4.18a

Figure 4.18c-e

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

• Group translocation of substances requires a transporter protein and PEP.

Movement Across Membranes

• Cytoplasm is the substance inside the plasma membrane

Cytoplasm

Figure 4.6a, b

• Nuclear area (nucleoid)• Plasmids:

• Small circular loops of DNA not connected to chromosomes

Nuclear Area

Figure 4.6a, b

Ribosomes

Figure 4.6a

Ribosomes

Figure 4.19

50S and 30S subunits making a 70S ribosome

Composed of RNA and protein

• Metachromatic granules (volutin)

• Polysaccharide granules• Lipid inclusions• Sulfur granules• Carboxysomes

• Gas vacuoles• Magnetosomes

Inclusions

•Phosphate reserves

•Energy reserves•Energy reserves•Energy reserves•Ribulose 1,5-diphosphate carboxylase for CO2 fixation•Protein covered cylinders•Iron oxide (destroys H2O2)

• Resting cells• Resistant to desiccation,

heat, chemicals• Bacillus, Clostridium• Sporulation: Endospore

formation• Germination: Return to

vegetative state

Endospores

Figure 4.21a

Eukaryotic Cells

• Comparing Prokaryotic and Eukaryotic Cells• Prokaryote comes from the Greek words for

pre-nucleus.• Eukaryote comes from the Greek words for

true nucleus.

Figure 4.22a

Flagella and Cilia

Figure 4.23a, b

• Microtubules • Tubulin• 9 pairs + 2 arrangements

Figure 4.23c

Eukaryotic Flagella

• Cell wall• Plants, algae, fungi• Carbohydrates

• Cellulose, chitin, glucan, mannan• Glycocalyx

• Carbohydrates extending from animal plasma membrane

• Bonded to proteins and lipids in membrane

Cell Wall

• Phospholipid bilayer• Peripheral proteins• Integral proteins• Transmembrane proteins• Sterols• Glycocalyx carbohydrates

Plasma Membrane

• Selective permeability allows passage of some molecules

• Simple diffusion• Facilitative diffusion• Osmosis• Active transport• Endocytosis

• Phagocytosis: Pseudopods extend and engulf particles

• Pinocytosis: Membrane folds inward bringing in fluid and dissolved substances

Plasma Membrane

• Cytoplasm Substance inside plasma membrane and outside nucleus

• Cytosol Fluid portion of cytoplasm• Cytoskeleton Microfilaments, intermediate

filaments, microtubules• Cytoplasmic streaming Movement of cytoplasm

throughout cells

Eukaryotic Cell

• Membrane-bound:• Nucleus Contains chromosomes• ER Transport network• Golgi complex Membrane formation and

secretion• Lysosome Digestive enzymes• Vacuole Brings food into cells and provides

support• Mitochondrion Cellular respiration• Chloroplast Photosynthesis• Peroxisome Oxidation of fatty acids;

destroys H2O2

Organelles

• Not membrane-bound:• Ribosome Protein synthesis• CentrosomeConsists of protein fibers and

centrioles• Centriole Mitotic spindle formation

Eukaryotic Cell

Nucleus

Figure 4.24

Endoplasmic Reticulum

Figure 4.25

• 80S (Svedberg)

• Membrane-boundAttached to

ER• Free

In cytoplasm• 70S

• In chloroplasts and mitochondria

Ribosomes

Golgi Complex

Figure 4.26

Lysosomes

Figure 4.22b

Vacuoles

Figure 4.22b

Mitochondrion

Figure 4.27

Chloroplast

Figure 4.28

Endosymbiotic Theory

Figure 10.2http://www.sumanasinc.com/webcontent/animations/content/organelles.html

Animation

Endosymbiotic theory2