Metabolism, Nutrition and Growth Flashcards
Catabolism
Transfer energy from complex molecules to ATP. Heat is released. Break things down
Anabolism
Transfer energy from ATP to complex molecules. Build things
Substrate-level phosphorylation
Transfer energy to ADP
Oxidative phosphorylation
Transfer of energy to electron carriers and ultimately to oxygen or other electron acceptors
Photophosphorylation
Transfer energy from the sun
Chemotrophs
Derive energy from chemicals
What are the two mechanisms of chemotrophs
-Respirations (O2, aerobic)
-Fermentation (no O2, anaerobic)
both involve oxidation-reduction reactions
What are the three types of final electron acceptors for metabolism?
- O2 aerobic respiration
- Inorganic compounds anaerobic respiration
- Organic compounds fermentation
What are the end products of fermentation
- acetate
- Propionate
- Butyrate
- Lactate
- Ethanol
How are complex organic substrates catabolized?
Extracellular enzymes break complex molecules to simple molecules and then the components of the is metabolized separately
How do bacteria reproduce?
Binary fission (asexual)
Generation time?
Time required for one cell to become two
Four phases of the growth curve
- Lag
- Log
- Stationary
- Death
Describe bacterial cell division
DNA replicates-> cell elongates- septum formation-> Septum completes to form distinct walls-> cells separate
Lag phase
Slow amount of growth at the start of the growth curve
Log phase
Greatest slope of growth were they start dividing. Exponentially growing
Stationary phase
Plateau where not dividing anymore
Death phase
Less cells are made compared to the amount of bacteria dying
How do we measure bacterial growth
- Direct
- Indirect
Direct method of bacterial growth
- Microscopic counts (count live and dead)
- Viable counts (only count live)
- count the number of colonies no the number of cells
What level of dilution is generally used for viable counts
ten-fold dilution through serial dilution
What is the spread-plate method?
Sample pipetted on agar and spread evenly then incubated
What is the pour plate method?
Add sample to empty plate then add medium and mix then incubate
What is the indirect methods of bacterial growth
Measure turbidity in spectrophotometer or absorbance of sample
