Microbio Week 4 Flashcards
Adaptation
Organism survives habitat through process of gradual adjustment of genetics, anatomy and physiology
Nutrient
Chemical compounds organisms obtain from outside the cell in order to sustain life
Biomolecules
Nucleic Acids
Carbs
Protein
Microbial molecule makeup
30% dry weight
70% water
How do Humans get Nitrogen?
Through organic compounds
How do these organic compounds get Nitrogen?
Nitrogen Fixation
Nitrogen Fixation
organisms take nitrogen from the atmosphere and convert it to ammonia.
Also known as “fix”
Performed by T. Erythraeum
and
Rhizobium
Nitrogen Cycle
- Ammonification
N2 converted to Ammonium (NH4+) by nitrogen fixing bacteria - Assimilation
Release of NH4+ during decomposition and/or being ingested - Nitrification (produces Nitrates)
Done by Chemoautotrophs who get energy from oxidizing organic compounds - Denitrification (anaerobic respiration)
In the absence of O2 use nitrates as final e- acceptor
Energy source of nutrients
Sun and Oxidizing Substances
Sun = Phototrophs
Oxidizing Substances = Chemo (chemicals) and Lithotrophs (Rock)
Carbon source of nutrients
Inorganic Carbon sources= Autotrophs
Organic Carbon sources = Heterotrophs
What molecules can pass through the Semi permeable PL bilayer
Small nonpolar
small noncharged
What molecules cannot pass through the Semi permeable PL bilayer
Large Polar Molecules
Ionized molecules
passive transport
Transport that does not require Energy
Diffusion
Movement of molecules from high conc to low conc
Facilitated diffusion
Use of transmembrane protein to allow substances to move down the conc gradient
Osmosis
Movement of water across cell membrane
(water is small, polar and easily passes through PL bilayer)
Hypotonic
The concentration of water inside the cell is low (due to high solute) so water moves into the cell
Cells without cell wall: Cells will expand as they fill with water
Cells with cell wall: Cells will expand to a limited capacity due to the cell wall
Isotonic
Movement of H20 is net zero due to their being relative equal conc of water both inside and outside the cell (same with solute)
Cells with both cell walls and no cell walls:
Cells will remain the same size
Hypertonic
The concentration of water inside the cell is high (due to low solute) so water moves out of the cell.
Cells without cell walls:
Cell will shrink and so will the Cell membrane
Cells with cell walls:
Cells won’t shrink due to cell wall. Instead the cell membrane and cell contents will shrink within the cell walls.
Adaptations to osmotic pressures
Depending on the environment microbes will use adaptations
Cell walls: Protects against too much water
Vacuoles: In microbes that lack a cell wall, vacuoles play an important role in storing and evacuating water
Halophiles
Bacteria + archaea that can grow in extremely high salt environments.
Active Transport
Use energy by cell to transport nutrients
Membrane proteins (pumps and permeases)
ATP is converted to ADP
Transport of nutrients faster than diffusion alone
or AGAINST diffusion gradient
Pumps and Permeases
Specific membrane bound transporter proteins that allow essential solutes to traverse the cell membrane.
Endocytosis
The taking in of a molecule by a cell by invagination of it’s membrane to form a vacuole
Exocytosis
A process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane
