CHARACTERISTICS OF PROKARYOTIC AND EUKARYOTIC CELLS CHAPTER 4
Cellular Characteristics
Cellular Characteristics 2 Domains, then Phyla 1 Domain, 4 kingdoms, then Phyla
Prokaryotic Cells Sizes 0.5 - 2µm (average) Shapes Cocci Bacilli Spirals
Prokaryotic Cell Arrangements Pairs Diplo- Tetrads Chains Strepto- Clusters Staphylo-
Typical Prokaryotic Cell
Gram Positive Cell Walls Peptidoglycan Thick layer Physical strength Teichoic Acids Molecular transport Viral attachments
Gram Negative Cell Walls Outer Membrane LPS components (Endotoxin) Periplasmic space Digestive Enzymes Protein pumps Chemical resistance Thin peptidoglycan layer
Other Cell Walls Acid Fast Cell Wall Mycolic acid or other lipid Gram positive structure Cell Wall Deficient bacteria
Prokaryotic Plasma Membrane Fluid Mosaic Proteins embedded in lipid Phospholipids Inner hydrophobic region Outer hydrophilic Chemical movement Small Uncharged
Prokaryotic Plasma Membrane
Internal structures Cytoplasm Watery medium Enzymes Cytoskeleton Ribosomes 70S Nuclear region
Endospores Stasis versus vegetative state Medically significant genera Resistances Dipicolinic acid
External Prokaryotic Structures Motility: Flagellae Axial filaments
Motility “Behaviors”
External Prokaryotic Structures Attachment: Pili Conjugation pili Fimbriae
Glycocalyx Capsule Attachment May limit penetration of some substances such as antibiotics, disinfectants Virulence factor Slime Layer Gliding substrate
Eukaryotic Cell Structure
Core Cellular Components Plasma membrane Cytoplasm Nucleus Ribosomes
Mitochondria and Chloroplasts
Mitochondria and Chloroplasts
Membranous Networks Endoplasmic Reticulum Rough Smooth Golgi apparatus
Eukaryotic Organelles/ Inclusions Lysosomes Peroxisomes Vacuoles Cytoskeleton
Motility Flagella Cilia Pseudopods
Cell Wall components Fungi Plants Protozoan pellicle
Endosymbiosis Evidence: DNA in Mt and chloroplasts 70S ribosomes No mitosis Two membranes
Eukaryotic/Prokaryotic symbiosis observed in today’s world (Protozoan termite inhabitant with internalized bacteria)
Movement across Membranes Diffusion Molecules move down a concentration gradient Size and charge are factors Osmosis Water molecule movement
Active Transport Protein pumps span the membrane ATP energy required Large charged molecules
Endo/Exocytosis Engulfment (Endocytosis) Eukaryotic activity Protozoan cells Phagocytic WBC Extrusion (Exocytosis)