BIOL 401 (GEN MICRO) Flashcards
Germ Theory of Disease
Many diseases are caused by microbes.
Koch’s Postulates
- Microbe is always present in diseased individuals.
- Microbe is grown outside the host.
- When microbe is introduced to healthy individuals, they become sick.
- The same microbe is present in new sick individuals and can be re-isolated.
Antoni van Leeuwenhoek
- Build a single-lens magnifier.
- First to observe single-celled microbes.
Robert Hooke
- Built the first compound microscope
- Observed mold
- Published Micrographia (with illustrations of microscopic organisms)
- Coined the term cell
A Microbe
An organism that is microscopic.
Microbe Morphologies
- Coccus (sphere)
- Rod (rod)
- Spirillum (bendy rod)
- Spirochete (red rope)
- Budding / Appendaged (stalks / hypha)
- Filamentous (strings)
Is a virus a microbe?
Yes
Pros of being small:
- Greater surface area / volume ratio
- Grows faster
*Less nutrient requirement
Alexander Fleming
- Discovered Penicillium (Penicillin)
Winogradsky Column
A stratified bacterial colony in glass, showing bacterial diversity.
Eukaryotes:
- Nucleus
- Golgi
- ER
- Peroxisomes
- Actin
- Myosin
- Tubulin
- Mitochondria
Biochemical Composition of Cells
- Water
*Essential Ions - Small Organic Molecules
*Macromolecules
Typical Bacterial Molecular Composition
- Water 70%
- Proteins 16%
- RNA 7%
- Lipids 4%
- DNA 1%
etc…
Dry Weight vs Wet Weight
- Water can vary dramatically
Bacterial Cell Overview
- Cytoplasm
- Cell Membrane
- Cell Wall
- Nucleoid (not membrane bound)
- Flagellum
Cytoplasmic Membrane
- Permeability
- Protein Anchor
- Energy Conservation
Cell Membrane:
- Lipid Bi-layer
*Divides Cytoplasm from the outside world. - Embeds proteins.
Membrane Lipids:
- Equal parts phospholipids and proteins.
Phospholipid:
Glycerol with ester links to two fatty acids and a phosphoryl head group.
A single layer of Phospholipids
Leaflets
Archaeal Lipids
- Number of rings increases with temperature.
- More rings = more rigidity.
- Monolayer
Membrane Proteins
- Provide structural support
- Environmental detection.
- Ion transport and energy storage.
Membrane Transport:
- Semi-permeable
- Selective transport
- Passive Diffusion follows the concentration gradient.
Transport Systems:
- Uniporter (out —> in)
- Antiporter (out / in <—–> out / in )
- Symporter ( out x2 —–> in x2 )
Cell Wall:
- Single molecule
- Helps withstand turgor pressure
Cell Envelope: Gram-positive vs Gram-negative
Gram Negative:
- Cell wall in the periplasm, which is thick.
- Single layer.
Gram Positive:
- Cell wall is external.
- Multiple Layers of peptidoglycan
START LEC 5
