week 4-microbial nutrition and growth Flashcards
Define microbial growth
Increase in number of cells(through reproduction)
Why do organisms require nutrients? Where do human pathogens get nutrients from?
So they can metabolize, so they can reproduce and grow
They get nutrients from humans
Name the 4 most common nutrients needed by microbes
Carbon
Hydrogen
Oxygen
Nitrogen
Why is it important that microorganisms have a carbon source?
essential for catabolizing to generate ATP
What are the main possible carbon sources
for a microorganism?
Carbs, amino acids, fats,(organic).
co2(inorganic)
Why do cells require water? Can they survive without water?
Need water so metabolic reactions can occur in the cell
Why is oxygen deadly for obligate anaerobes?
Lacks protective enzymes necessary that would break down the toxic oxygen forms
Why is hydrogen essential for life
helps form bonds
in water
How can obligate aerobe protect itself from toxic o2
why can’t anaerobe protect itself
aer- makes enzymes to break down toxic 02
an-does not make the enzymes required to fight toxic forms of 02
Why is nitrogen important for a microbe?
Found in all amino acids
part of nitrogenous bases (DNA RNA)
D-ATCG
R-AUCG
Why is phosphorous important for microbes?
P- important for backbone of DNA + RNA
also P in ATP
optimal
best case scenario for a microorganism
optimal temp, ph etc.., there will always be an optimal range for the organism
Briefly describe the different types of physical growth factors that can affect a microorganism -Temp
increasing temp from optimal-denatures proteins(loses function)/liquify cell membrane
too low from optimal-membrane becomes rigid and fragile-slow down metabolism
each organism can survive over a specific temperature range-minimum temp and max temp
Briefly describe the different types of physical growth factors that can affect a microorganism -PH
Changes in ph away from optimal ph can denature proteins
normally a very shallow range of ph
Briefly describe the different types of physical growth factors that can affect a microorganism -Hydrostatic pressure
Water exerts pressure in proportion to its depth.
Their membranes and enzymes depend on this pressure to maintain their three- dimensional, functional shape.
like human in deep sea- too high of pressure and 3d shape will change
Hypotonic solution-osmotic pressure
less salt in water then cell
water will be drawn into cell-causing it to burst
Hypertonic solution-osmotic pressure
Very salty solution-more salt then water
Water will be drawn out of cell, causing cell to shrink
Isotonic solution-osmotic pressure
level of salt in cell and salt in water are same
There is NO movement of water(no osmosis)
Briefly describe the different types of physical growth factors that can affect a microorganism -osmotic pressure
More solutes = higher osmotic pressure.
Osmosis is the movement of water—water follows salt (water moves toward the area with higher solute concentration).
Psychrophiles
low temp
mesophiles
body temp
thermophiles
higher temps
barophiles
extreme pressure
Neutrophiles
neutral ph
