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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Chapter 4 Prokaryotic Cell Functional Anatomy of Prokaryotic and Eukaryotic Cells.

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Presentation on theme: "Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Chapter 4 Prokaryotic Cell Functional Anatomy of Prokaryotic and Eukaryotic Cells."— Presentation transcript:

1 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Chapter 4 Prokaryotic Cell Functional Anatomy of Prokaryotic and Eukaryotic Cells Bio 205

2 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Prokaryotic Cells Comparing Prokaryotic and Eukaryotic Cells Prokaryote comes from the Greek words for prenucleus. Eukaryote comes from the Greek words for true nucleus.

3 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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

4 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Average size: µm  µm Basic shapes:

5 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Unusual shapes Star-shaped Stella Square Haloarcula Most bacteria are monomorphic A few are pleomorphic (variable shapes during life cycle) Figure 4.5

6 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pairs: diplococci, diplobacilli Clusters: staphylococci Chains: streptococci, streptobacilli Arrangements

7 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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

8 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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

9 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Flagella Arrangement Figure 4.7

10 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Brownian Motion Flagella motion

11 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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

12 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Endoflagella In spirochetes Anchored at one end of a cell Rotation causes cell to move Axial Filaments Figure 4.10a

13 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fimbriae allow attachment Pili are used to transfer DNA from one cell to another Figure 4.11 Fimbriae

14 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Prevents osmotic lysis Made of peptidoglycan (in bacteria) Cell Wall Figure 4.6a, b

15 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Polymer of disaccharide N-acetylglucosamine (NAG) & N-acetylmuramic acid (NAM) Linked by polypeptides Peptidoglycan Figure 4.13a

16 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.13b, c

17 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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

18 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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

19 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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 form channels through membrane Gram-Negative Outer Membrane

20 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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

21 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Mycoplasmas Lack cell walls Sterols in plasma membrane Archaea Wall-less, or Walls of pseudomurein (lack NAM and D amino acids) Atypical Cell Walls

22 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lysozyme digests disaccharide in peptidoglycan. Penicillin inhibits peptide bridges in peptidoglycan. Protoplast is a wall-less cell Gram-positive cell. Spheroplast is a wall-less Gram-negative cell. L forms are wall-less cells that swell into irregular shapes. Protoplasts and spheroplasts are susceptible to osmotic lysis. Damage to Cell Walls

23 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Plasma Membrane Figure 4.14a

24 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Plasma Membrane Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane proteins Figure 4.14b

25 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Membrane is as viscous as olive oil. Proteins move to function Phospholipids rotate and move laterally Fluid Mosaic Model Figure 4.14b


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