Microbial Metabolism and Growth Flashcards
(63 cards)
No matter how microbes obtain their energy source, what do they generally want to use for this?
Glucose
How do chemoheterotrophs get their glucose?
By importing it directly using transporters
How do chemoautotrophs get their glucose?
By fixing carbon to create glucose themselves using the Calvin Cycle
Why do microbes use glucose specifically?
-Glucose is a great electron donor
-Oxygen is a great electron acceptor
What are the phases of bacterial growth?
- Lag phase
- Log phase
- Stationary phase
- Death phase
Lag phase of bacterial growth
no increase in # of living bacterial cells
Log phase of bacterial growth
exponential increase in # of living bacterial cells
Stationary phase of bacterial growth
plateau in # of living bacterial cells; rate of cell division and death ~ equal
Death phase of bacterial growth
exponential decrease in # of living bacterial cells
Which is easier to metabolize? Glucose or lactose
glucose
Why is glucose easier to metabolize than lactose?
Lactose produces 2 glucose molecules BUT at the cost of 2 additional ATP and 6 enzymes
How do protons power ATP synthase?
Via proton motive force
Since prokaryotes and unicellular eukaryotes are metabolically diverse and flexible, what ability do they have regarding metabolic strategies?
They are able to quickly adjust metabolic strategies within a single cell type
In the absence of C6 or C4, some bacteria can use ____ with the ____________ cycle.
C2, glyoxylate
Isocitrate lyase
Bypasses number of TCA steps and creates an intermediate -> glyoxylate
Glyoxylate Cycle
Allows microbes to grow off of fatty acids as fatty acid degradation produces acetate
What are the variations on traditional aerobic central metabolism?
- Glyoxylate cycle
- Mixed Acid Fermentation
Mixed Acid Fermentation
-Anaerobic, low energy
-Pyruvate is converted to lactic acid (recover 1 NAD)
-Acetyl CoA is converted to ethanol and acetate (Recover 2 NAD, gain 1 ATP)
Lactic acid bacteria can “___________” and is why they are often considered “___________.”
niche construct, keystone species
Niche Construction
A process where organisms change their environment in ways that can affect the evolutionary dynamics of themselves and of other organisms
Keystone Species
A species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically
Is lactic acid fermentation a type of anaerobic respiration?
No because cellular respiration has a specific definition
Cellular Respiration
The act of oxidizing highly reduced compounds (FADH, NADH) to establish an electrochemical gradient (often a proton gradient) across a membrane. Protons moved down the gradient (across the membrane) through the proton channel of ATP synthase, creating ATP.
Aerobic respiration
Terminal electron receptor is oxygen
