2008 Functional Anatomy of Prokaryotic and Eukaryotic Cells

2008 Prokaryotic Cells Comparing Prokaryotic and Eukaryotic Cells Prokaryote comes from the Greek words for prenucleus. Eukaryote comes from the Greek words for true nucleus.

2008 One circular chromosome, not in a membrane No histones No organelles Peptidoglycan cell walls Binary fission ProkaryoteEukaryote Paired chromosomes, in nuclear membrane Histones Organelles Polysaccharide cell walls Mitotic spindle

2008 Average size: µm  µm Basic shapes:

2008 Unusual shapes Star-shaped Stella Square Haloarcula Most bacteria are monomorphic A few are pleomorphic Figure 4.5

2008 Pairs: diplococci, diplobacilli Clusters: staphylococci Chains: streptococci, streptobacilli Arrangements

2008 Outside cell wall Usually sticky A capsule is neatly organized A slime layer is unorganized & loose Extracellular polysaccharide allows cell to attach Capsules prevent phagocytosis Glycocalyx Figure 4.6a, b

2008 Outside cell wall Made of chains of flagellin Attached to a protein hook Anchored to the wall and membrane by the basal body Flagella Figure 4.8

2008 Flagella Arrangement Figure 4.7

2008 Flagella arrangement flash animation

2008 Figure 4.8

2008 Flagella structure flash animation

2008 Rotate flagella to run or tumble Move toward or away from stimuli (taxis) Flagella proteins are H antigens (e.g., E. coli O157:H7) Motile Cells

2008 Motile Cells Figure 4.9

2008 Endoflagella In spirochetes Anchored at one end of a cell Rotation causes cell to move Axial Filaments Figure 4.10a

2008 Motility flash animation

2008 Fimbriae allow attachment Pili are used to transfer DNA from one cell to another Figure 4.11

2008 Prevents osmotic lysis Made of peptidoglycan (in bacteria) Cell Wall Figure 4.6a, b

2008 Polymer of disaccharide N-acetylglucosamine (NAG) & N-acetylmuramic acid (NAM) Linked by polypeptides Peptidoglycan Figure 4.13a

2008 Figure 4.13b, c

2008 Thick peptidoglycan Teichoic acids In acid-fast cells, contains mycolic acid Gram-positive cell wallsGram-negative cell walls Thin peptidoglycan No teichoic acids Outer membrane

2008 Teichoic acids: Lipoteichoic acid links to plasma membrane Wall teichoic acid links to peptidoglycan May regulate movement of cations Polysaccharides provide antigenic variation Gram-Positive cell walls Figure 4.13b

2008 Lipopolysaccharides, lipoproteins, phospholipids. Forms the periplasm between the outer membrane and the plasma membrane. Protection from phagocytes, complement, antibiotics. O polysaccharide antigen, e.g., E. coli O157:H7. Lipid A is an endotoxin. Porins (proteins) form channels through membrane Gram-Negative Outer Membrane

2008 Gram-Negative Outer Membrane Figure 4.13c

2008 Crystal violet-iodine crystals form in cell Gram-positive Alcohol dehydrates peptidoglycan CV-I crystals do not leave Gram-negative Alcohol dissolves outer membrane and leaves holes in peptidoglycan CV-I washes out Gram Stain Mechanism

2008 Mycoplasmas Lack cell walls Sterols in plasma membrane Archaea Wall-less, or Walls of pseudomurein (lack NAM and D amino acids) Atypical Cell Walls

2008 Lysozyme digests disaccharide in peptidoglycan. Penicillin inhibits peptide bridges in peptidoglycan. Protoplast is a wall-less cell. Spheroplast is a wall-less Gram-positive cell. L forms are wall-less cells that swell into irregular shapes. Protoplasts and spheroplasts are susceptible to osmotic lysis. Damage to Cell Walls

2008 Plasma Membrane Figure 4.14a

2008 Plasma Membrane Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane proteins Figure 4.14b

2008 Membrane is as viscous as olive oil. Proteins move to function Phospholipids rotate and move laterally Fluid Mosaic Model Figure 4.14b

2008 Selective permeability allows passage of some molecules Enzymes for ATP production Photosynthetic pigments on foldings called chromatophores or thylakoids Plasma Membrane

2008 Damage to the membrane by alcohols, quaternary ammonium (detergents) and polymyxin antibiotics causes leakage of cell contents. Plasma Membrane

2008 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

2008 Movement Across Membranes Figure 4.17

2008 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

2008 Figure 4.18c-e

2008 Active transport of substances requires a transporter protein and ATP. Group translocation of substances requires a transporter protein and PEP. Movement Across Membranes

2008 Cytoplasm is the substance inside the plasma membrane Cytoplasm Figure 4.6a, b

2008 Nuclear area (nucleoid) Nuclear Area Figure 4.6a, b

2008 Ribosomes Figure 4.6a

2008 Ribosomes Figure 4.19

2008 Metachromatic granules (volutin) Polysaccharide granules Lipid inclusions Sulfur granules Carboxysomes Gas vacuoles Magnetosomes Inclusions Phosphate reserves Energy reserves Ribulose 1,5- diphosphate carboxylase for CO 2 fixation Protein covered cylinders Iron oxide (destroys H 2 O 2 )

2008 Resting cells Resistant to desiccation, heat, chemicals Bacillus, Clostridium Sporulation: Endospore formation Germination: Return to vegetative state Endospores

2008 Figure 4.21a

2008 Eukaryotic Cells Comparing Prokaryotic and Eukaryotic Cells Prokaryote comes from the Greek words for prenucleus. Eukaryote comes from the Greek words for true nucleus.

2008 Figure 4.22a

2008 Flagella and Cilia Figure 4.23a, b

2008 Microtubules Tubulin 9 pairs + 2 arrangements Figure 4.23c

2008 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

2008 Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane proteins Sterols Glycocalyx carbohydrates Plasma Membrane

2008 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

2008 CytoplasmSubstance inside plasma membrane and outside nucleus CytosolFluid portion of cytoplasm CytoskeletonMicrofilaments, intermediate filaments, microtubules Cytoplasmic streamingMovement of cytoplasm throughout cells Eukaryotic Cell

2008 Membrane-bound: NucleusContains chromosomes ERTransport network Golgi complexMembrane formation and secretion LysosomeDigestive enzymes VacuoleBrings food into cells and provides support MitochondrionCellular respiration ChloroplastPhotosynthesis PeroxisomeOxidation of fatty acids; destroys H 2 O 2 Organelles

2008 Not membrane-bound: RibosomeProtein synthesis CentrosomeConsists of protein fibers and centrioles CentrioleMitotic spindle formation Eukaryotic Cell

2008 Nucleus Figure 4.24

2008 Endoplasmic Reticulum Figure 4.25

S Membrane-boundAttached to ER FreeIn cytoplasm 70S In chloroplasts and mitochondria Ribosomes

2008 Golgi Complex Figure 4.26

2008 Lysosomes Figure 4.22b

2008 Vacuoles Figure 4.22b

2008 Mitochondrion Figure 4.27

2008 Chloroplast Figure 4.28

2008 Endosymbiotic Theory Figure 10.2