1 Prokaryotic Cell Envelopes n Filename Envelope ppt

1 Prokaryotic Cell Envelopes n Filename: Envelope. ppt Hugh B. Fackrell 9/15/2020

2 Presentation Outline n Cell wall – Gram reaction – Gram positive vs Gram negative – Gram wall Cell Capsule n Flagella n Pili n 9/15/2020

3 Background Terms & Concepts Proteins n Membranes (membr. ppt) n Formation of lipid bilayers (membr. ppt) n Prokaryotes vs eukaryotes n Evolution of eukaryotes n 9/15/2020

4 Prokaryotes Size: 1 -10 m n Flagella: simple, 2 proteins n Capsule: extracellular polymer n Cell wall: usual, complex n Plasma membrane: no carbohydrates or sterols n Ribosomes: small(70 S) n Cell division: binary fission n 9/15/2020

5 Cell Envelope Cell membrane n Cell Wall n Capsule (glycocalyx) n 9/15/2020

6 Diagram of prokaryote 9/15/2020

7 Plasma membranes in cell 9/15/2020

8 Phospholipid bilayer 9/15/2020

9 Phospholipid Molecules in Bilayer 9/15/2020

10 Plasma Membrane: Eukaryote 9/15/2020

11 Cell wall is Rigid 9/15/2020

12 Gram Positive Cell Wall 9/15/2020

13 Gram Positive Cells 9/15/2020

14 Gram Positive Cell Wall 9/15/2020

15 Lysozyme Site 9/15/2020

16 NAG & NAM 9/15/2020

17 Gram Negative Cell Wall 9/15/2020

18 Gram Negative Cells 9/15/2020

19 Gram Negative Cell Wall 9/15/2020

20 Gram Negative Cell Wall 9/15/2020

21 Bacterial Cell Walls 9/15/2020

22 Bacterial Wall [detail] 9/15/2020

23 Isolated Murein Layer 9/15/2020

24 Capsule Deposited outside of cell wall n Polymer n – Carbohydrate – Protein Antiphagocytic n Receptors n Antigenic n Klebsiella pneumoniae negatively stained 9/15/2020

25 Bacterial Capsule n Negatively stained with India ink particles Bacteroides thetaiotaomicron 9/15/2020

26 Bacterial capsule Method: Differential interference phase contrast microscopy n Capsule appears larger than last slide n Bacteroides thetaiotaomicron 9/15/2020

27 Surface attachment by Glycocalyx 9/15/2020