Question

Microbiology Mini-Tutorial: Fundamentals of Microbial Growth

Answer 1

Note: This is a reference for educational/studying purposes, not a question, please save all comments or questions for the end.

Answer 2

\({\bf{Quantifying~Bacterial~Growth}}\)
- spectrophotometry: using absorbance to quantify bacterial content
- microscopy: using light/magnification
- direct counting: slow and time consuming
- viable plate counting (growing colony from a sample and conducting a serial dilution, then determining the number of original viable cells)
- molecular methods: ex. PCR
- dry weight/mass

\({\bf{Doubling~Equation}}\) N = N_0 * 2^n where n is the generation number, obtained by dividing total time/time for each division

\({\bf{Factors~affecting~Growth}}\)
- temperature, pH, salinity, osmotic pressure, oxygen content
- can be obligate/facultative aerobes/anaerobes

\({\bf{Growth~Stages}}\)
1. lag phase: bacteria are metabolically active but not dividing
2. exponential/logarithmic phase, shows exponential growth
3. stationary phase: death and growth rate begin to even out
4. death phase, death rate starts to exceed growth rate

\({\bf{Growth vs. Temperature}}\)
-the temperature range preferred depends on the species of bacteria
-from cold to hot we describe them as: psychrophiles, mesophiles, thermophiles, hyperthermophiles, and hypothermophiles
- human body temp. favors mesophiles

\({\bf{Energy~and~Metabolism}}\)
- electron transport chain, uses the reduction of NADH+ and the H+ gradient to generate ATP
- total TCA cycle: generates 36-38 ATP
- pyruvate converted to acetyl CoA before entering the cycle

Answer 3

This is the end of my tutorial; I hope you found it helpful. If you have any ∗relevant∗ comments or questions I will attempt to address them to the best of my ability.
Thank you for reading!