Slide 1

2004 Wadsworth Thomson Learning Chapter 4 Prokaryotic and Eukaryotic Cells Slide 2 2004 Wadsworth Thomson Learning Prokaryotic vs. Eukaryotic Prokaryotic No nucleus No membrane- bound organelles Cell wall contains peptidoglycan Size: less than several micrometers Eukaryotic Nucleus Membrane-bound organelles No peptidoglycan if cell wall even present Size: may be 10 times larger Slide 3 2004 Wadsworth Thomson Learning Prokaryotes--Cell Structure Appendages on outside Capsule and envelope outer membrane (some) periplasmic space between two membranes cell wall (most) cytoplasmic membrane Cytoplasm nucleoid ribosomes storage granules Figure 4.3 Slide 4 2004 Wadsworth Thomson Learning Prokaryotes: Outer membrane Lipid bilayer phospholipid lipopolysaccharide (LPS) endotoxin lipid A porins lipoprotein anchors to cell wall unique to bacteria Figure 4.5 Slide 5 2004 Wadsworth Thomson Learning Prokaryotes: Cell wall Provide shape Withstand turgor pressure (osmotic pressure) Composition peptidoglycan: murein part protein (peptido-) part polysaccharide (-glycan) chains of alternating polysaccharide N-acetylglucosamine (NAG) N-acetylmuramic acid (NAM) cross-linked with peptides Figure 4.6 Slide 6 2004 Wadsworth Thomson Learning Spherical bacteria Cocci (Coccus) single pair diplococcus group of four tetrads chain streptococcus clusters staphylococcus Figure 4.7 Slide 7 2004 Wadsworth Thomson Learning Rod-shaped bacteria Bacilli (Bacillus) Arrangement single pair diplobacillus chain streptobacillus Figure 4.7 Slide 8 2004 Wadsworth Thomson Learning Spiral and other shaped Spiral shaped spirilla (spirillum) Comma shaped vibrio Other Square Star-shaped Figure 4.7 Slide 9 2004 Wadsworth Thomson Learning Cytoplasmic membrane Contain the cytoplasm Both Eucaryotic and Procaryotic regulate passage into and out of cell Components phospholipid bilayer proteins transmembrane cytoplasmic peripheral Fluidity of membrane Figure 4.8 Slide 10 2004 Wadsworth Thomson Learning Prokaryotes: Appendages Pili (Pilus) or fimbriae attachment Flagella (flagellum) locomotion propeller-like motion structure helical-shaped filament hook attached to anchor basal body anchors in membrane Figure 4.10 Slide 11 2004 Wadsworth Thomson Learning Prokaryotes: Movement Chemotaxis sense chemicals Phototaxis sense light intensity Aerotaxis favorable oxygen concentrations Magnetotaxis move along magnetic lines Slide 12 2004 Wadsworth Thomson Learning Prokaryotes: Chemotaxis Run: swimming motion propelled by flagella working in unison Tumble: senses the chemical concentration flagella loosen apart repeat actions changing direction slightly Figure 4.12 Slide 13 2004 Wadsworth Thomson Learning Prokayrotes: Outermost layer Capsule, slime layer, glycocalyx Slimy or gummy substance Composition varies Most made of polysaccharides Function Protection Against drying out Against phagocytosis Adhere to surface pathogenesis Slide 14 2004 Wadsworth Thomson Learning Prokaryotes: Cytoplasm Primarily water Site of metabolism Nucleoid region contains DNA Ribosomes site of protein synthesis Inclusion bodies storage granules Gas vacuoles Chlorosomes magnetosomes Slide 15 2004 Wadsworth Thomson Learning Prokaryotes: Endospores Resting structures formed inside cell Conditions unfavorable for growth extreme heat dehydration toxic chemicals radiation Long-term survival hundreds of years Slide 16 2004 Wadsworth Thomson Learning Sporulaton Unequal cell division begins Cytoplasm divides vegetative cell forespore DNA in both parts Figure 4.15 Slide 17 2004 Wadsworth Thomson Learning Sporulation Thick protective wall forms peptidoglycan--different than vegetative cell keratinlike Spore body contains all essential cell components Vegetative cell lyses--releases endospore Germinates when conditions become favorable Figure 4.15 Slide 18 2004 Wadsworth Thomson Learning Structure of Archaea Cell walls archaea have protein or pseudomurein Plasma membrane fatty acids attached to glycerol differently bacteria--ester bond archaea-ether bond stronger bond withstand harsh conditions Figure 4.16 Slide 19 2004 Wadsworth Thomson Learning Eukaryotes: Appendages Flagella Purpose motility wave-like motion (not propeller-like) Composition microtubules 9 pair surrounding 2 central Cilia shorter more numerous Slide 20 2004 Wadsworth Thomson Learning Eukaryotes: Cell wall and cytoplasmic membrane Cell wall great diversity many cells dont have (animal cells) composition varies Cytoplasmic membrane similar to prokaryotes Slide 21 2004 Wadsworth Thomson Learning Eukaryotes: Cytoskeleton Function structure movement cytoplasmic streaming transport of molecules cell division Fibrous protein structures three types Microtubules Microfilaments Intermediate filaments Figure 4.17a Slide 22 2004 Wadsworth Thomson Learning Eukaryotes: Nucleus Function contain the DNA Nuclear membrane lipid bilayer surrounding nucleus nuclear pores passage of material Nucleoplasm gelatinous matrix of nucleus Nucleoli dense masses of RNA and protein Slide 23 2004 Wadsworth Thomson Learning Eukaryotes: Cytomembrane system Function sorting and transport of synthesized molecules Components Endoplasmic reticulum (ER) rough ER ribosomes attached smooth ER no ribosomes Figure 4.21 Slide 24 2004 Wadsworth Thomson Learning Eukaryotes: Cytomembrane system Golgi apparatus stacks of flattened membrane sacs molecules are modified Vessicles transport from ER to Golgi from Golgi to final destination inside the cell outside the cell Figure 4.22 Slide 25 2004 Wadsworth Thomson Learning Eukaryotes: Mitochondria and Chloroplasts Energy production Double membrane system outer membrane--separate from rest of cell inner membrane--highly folded Mitochondria respiration Chloroplasts photosynthesis Slide 26 2004 Wadsworth Thomson Learning Cell Division: Mitosis Cell division ending in two identical cells Stages: Interphase DNA decondenses DNA replicated Mitosis Prophase Metaphase Anaphase Telophase Figure 4.19 Slide 27 2004 Wadsworth Thomson Learning Cell division: Mitosis Early prophase double number of chromosomes chromosomes condense Late prophase spindle forms chromosomes condensed Figure 4.19 Slide 28 2004 Wadsworth Thomson Learning Cell division: Mitosis Metaphase chromosomes attach to spindle fibers chromosomes line up middle of cell Anaphase chromosomes moved to opposite ends of cell Figure 4.19 Slide 29 2004 Wadsworth Thomson Learning Cell division: Mitosis Telophase chromosomes decondense nuclear membrane reforms cell separation occurs Interphase identical daughter cells Figure 4.19 Slide 30 2004 Wadsworth Thomson Learning Cell division: Meiosis Cell division in reproductive cells Final cells half the chromosome number haploid number Meiosis I duplication of chromosomes crossing-over genetic variability Meiosis II reduce chromosome number Slide 31 2004 Wadsworth Thomson Learning Cell division: Meiosis Prophase I Homologous chromosome pair up Crossing over Nuclear membrane disintegrates Chromosomes condense Metaphase I Chromosomes align in center Attach to spindle fibers Figure 4.20 Slide 32 2004 Wadsworth Thomson Learning Cell division: Meiosis Anaphase I Chromosome pairs separate to different ends Telophase I Cells divide Single set of chromosomes (haploids) Figure 4.20 Slide 33 2004 Wadsworth Thomson Learning Cell division: Meiosis Prophase II Duplicates of each chromosome Metaphase II Chromosomes line up in the middle Attached to fibers Figure 4.20 Slide 34 2004 Wadsworth Thomson Learning Cell division: Meiosis Anaphase II Chromosome separate to opposite ends Telophase II Cell divides Each daughter cell has single copy of each chromosome Reproductive cell Egg or sperm Figure 4.20 Slide 35 2004 Wadsworth Thomson Learning Simple diffusion Molecules move randomly Evenly distribute Figure 4.24 Slide 36 2004 Wadsworth Thomson Learning Osmosis Water movement Cross membrane from low concentration of solute to high High solute concentration hypotonic cell swells Low solute concentration hypertonic shrinks Equal solute concentration Isotonic Figure 4.25 Slide 37 2004 Wadsworth Thomson Learning Membrane transport Facilitated diffusion no energy required carrier protein high to low concentration Active transport energy required carrier protein low to high concentration Group translocation unique to bacteria modification as well as transport Figure 4.26 Slide 38 2004 Wadsworth Thomson Learning Eukaryotic membrane transport Endocytosis bring inside the cell phagocytosis engulfing cells pinocytosis cell drinking Exocytosis exporting out Figure 4.26