Microbiology 303Cell structure and function
OutlineI. General Thoughts about Cell Structure II. Visualizing Microorganisms III. The Cytoplasm A. Nucleoid B. Ribosomes C. Cytoskeleton D. Inclusions IV. The Membrane A. Membrane Lipids B. Transport Across the membrane V. Outer Layers A. Cell envelopes i. Peptiodglycan ii. Gram-positive iii. Gram-Negative B. Cell wall diversity C. Capsules D. Pili E. Flagella VI. Archaea A. Cell Membranes B. Cell Wall Types VII. Eukaryotes A. Organelles B. Origin of Eukaryotes
Learning outcomes•Be able to recognize the structures of the monomersthat make up the basic building blocks of the cell•Be able to assign a function to a structural unit.Cytoplasm, nucleoid, membrane.•Be able to recognize DNA and protein structures•Decide on the correct type of microscopy andsample preparation for a given situation.•Explain how bright-field microscopy works and whyspecimens must be stained.
Learning outcomes•List two structures that both Gram-negative and Gram-positive cellshave in common, and provide the function of each.•List two structures that are unique to Gram-negative and to Gram-positive cells, and provide the function of each.•Distinguish between cell envelope structures (e.g., membranes andcell wall, etc.) in Gram- positive and Gram-negative bacteria.•Compare and contrast the different cellular transport processes(e.g., facilitated diffusion, ion driven transport/simple transport,ABC transporter, group translocation, etc.) with regard to theproteins involved and the energy source used.•Distinguish between different modes of motility•Explain what chemotaxis is and how it works•Compare and contrast the structure of cell membranes and cellwalls in Bacteria, Archaea, and Eukarya
For microbes: the cell is the organism and Cells are Cells•The basic unit of life•All cells are made of basically the same things:proteins, nucleic acids, lipids, sugars, andvarious small molecules•Membranes are the critical divider betweenself and non-self–Maintain barrier–Sense outside world–Contain cell components
Microbes have the same basic life functions asmacrobes(as populations)Common to all microbes-3, 4 and 5 many but not all microbes
On being small: surface to volume ratio
Cell shape variesBacillus (rod)Spirochete
Why so many different shapes?•Nutrient acquisition•Defense from predators–Phagocytes that eat cells, multicellular microbivores•Attachment to surfaces•Dispersal•Motility•Differentiation•Why not?
Visualized Structures Using•Light microscope•Fluorescent microscope•Phase-contrast microscope•Confocal microscope•Atomic force microscope•Electron microscope (SEM, TEM)•X-ray CrystallographyJanice Carr/ Jeff Hageman, M.H.S.CDC
Visualizing microbes 1. Your brilliant, but absent-minded, research mentor is terribly excited.
- Spring '19