Lecture #3 - Microbial Growth & Nutrition Flashcards
Macronutrients
- Elements required in LARGE amounts to build macromolecules (b/c you req. a lot of it)
- The building blocks of cell material
think: screw to build house is a macronutrient b/c you need A LOT of it to build the house
How much of dry weight do Macronutrients makeup?
C,H,O,N,P and S makeup >90% of the dry weight of the cell
What does “dry weight of the cell” mean?
dehydrated - means that water is 60-80% of the weight of cell will skew the #’s too much so you consider cell in dehydrated state to see how the atoms will be req.
Protein–C,H,O,N(andS)
• Polymer of made of building blocks – amino acids
How much of dry weight do Protein–C,H,O,N(andS) makeup?
> 50% of cell dry weight
- b/c protein is the workhouse of the cell - big deal in so many things, therefore cell must have adequate amounts
Protein–C,H,O,N(andS); which are from where?
C,H,O,N - backbone of an AA
S - 2/20 AA’s (cysteine/methionine)
Lipids–C,H,O(andP)
- Building blocks = fatty acids and glycerol
- Ex) Phospholipids
- mostly HYDROPHOBIC structure
- C, H - contributes to the non-polar hydrophobic character (therefore most of hydrophobic structure)
- O - (small amount) within hydroxyl groups of f.a. tails & in glycerol comp. of neck of structure
- P - specifically found in PL’s - head group comp
Carbohydrates – C, H, O (and N)
- Building blocks = sugars
- Ex. Polysaccharides and peptidoglycan
(monosaccharide (building blocks) form polysaccharides that take on specific terms like PD)
C: 1
H: 2
O: 1
(glucose C6H12O6)
Carbohydrates – C, H, O (and N)
N is a…
sugar DERIVATIVE
- not true sugar but if it has N its a derivative of a sugar
- can be there, but never part of glucose, galactose, sucrose, ribose, deoxyribose, etc.
Protein is ____% of dry weight
55
RNA is ____% of dry weight
20.5
Why is RNA such a large value of % dry weight comp. of cell?
PRE-CURSOR (transcript) to actually give you your protein which you have so much of (55%)
Nucleicacids–C,H,O,N,P
- Building blocks = nucleotides (indiv. pieces used to form DNA & RNA)
- Ex. DNA and RNA
Describe where each Nucleicacids–C,H,O,N,P are part of
C,H,O - part of sugar (ribose or deoxyribose)
N - part of nitrogenous base
P - part of phosphate group
Carbon is ___% of dry weight
50
backbone for all organic macromolecules
Hydrogen is ___% of dry weight
8.2
only forms 1 cov. bond
Sulfur is ___% of dry weight
1.8
2/20 AA’s
Selenium is ___% of dry weight
<0.01
- used to form selenocysteine (an AA MODIFICATION)
- even though its small you still need it
Other Macronutrients – inorganic ions (K, Mg, Ca, Fe)
• Often serve as metabolic CO-factors (a sidekick)
• NON-protein component required for enzyme function
- enzyme itself is a PROTEIN
- Enzymes involved in protein synthesis require K+
- Cytochromes (e- carriers) require Fe2+ (affects reduction potential, which affects e- affinity so those e- carriers will have diff. affinity (pull/desire for those e-‘s) which will correlate with amount of energy that’s released)
- Other functions:
- Mg2+ helps stabilize membranes and nucleic acids (can relieve charge repulsion on PM)
- Ca2+ helps stabilize cell walls, and plays a role in heat stability of endospores (helps make inside of endospore stable - Ca2+/dipicolinic acid)
Describe glycolysis
glucose –> glucose 6-P
glucose –>(hexokinase - protein; has cofactor of Mg2+, allowing formation of G-6P) glucose 6-P (-)ly charged
Mg2+ (NON-protein) (+)ly charged (therefore provides temporary relief for charge repulsion that (-) charges will have with 1 another
ATP –> ADP Pi comes off and goes to form G-6P
_____ of the macronutrients should be considered when making media
ALL
therefore, DON’T expect them to grow if you left out a source (think: forgot screws - key comp)
ALSO, not all organisms like the same thing - may not like concentrations b/c they are wrong
CANNOT grow every single organism in a lab, no matter how hard you try (some are too partic)
Micronutrients
• Elements required in VERY SMALL amounts (trace elements)
- doesn’t mean they are unimp. ( they are CRITICAL for their function)
- just b/c you don’t need a lot of something, doesn’t mean you can remove it & it still will lead to an unhindered life (absolutely critical you always have this material in the cell for full growth & success & viability)
• Usually serve as COFACTORS for enzymes
- provide a support (usually ionic stability)
- can’t function without its sidekick
• Ex) Mn, Zn, Co, Ni, Cu, Mo
• Se is required to make the unusual amino acid selenocysteine (derivative of cysteine AA (has S); been modified - allowing add. function/diversity)
Micronutrients
Usually serve as cofactors for enzymes
• Ex) Mn, Zn, Co, Ni, Cu, Mo
Describe Zn2+
(can’t function without its sidekick; provide a support usually ionic stability)
Zn2+ to stabilize active site of the enzyme
- anywhere you have a (-) charge with your substrate, the (+)ity can provide ionic stability or electrostatic activity
Carboxypeptidase
Why is C so abundant, & O and H are less?
C - can form 4 cov. bonds - excellent candidate to build lipids, carbs, AA’s & nucleotides b/c you can build elaborate castles (lots of diff. options on how they can be built)
O - can form 2 cov. bonds - less diversity/options
H - con form 1 cov. bond
Growth factors
- Small organic molecules REQUIRED for growth (BUT there are things the cell can sometimes make)
- IF an organism CANNOT SYNTHESIZE the growth factor, then it must be ADDED to medium to grow that microbe in the lab
IF an organism CANNOT SYNTHESIZE the growth factor, then…
it must be ADDED to medium to grow that microbe in the lab
If you have an organism that CANNOT synthesize a GF, then gets put into a growth medium that doesn’t have that GF? Will it grow?
- either they won’t grow or they’ll grow abnormally (certain pathway for ex won’t be prod.)
- depends on what it was critical for
- expect destruction of some kind
- GFs can either be made b/c organism has a recipe within its genetic makeup to actually cell for that OR it must be provided
If you have an organism who CAN synthesize the GF. Will it rather wanna make it on its own or take what you provided in the GM? You can give or not give it to him. Would he rather you give it to him or make it on its own?
- GIVE IT TO HIM –> b/c LESS energy (less time/work)
think: someone can buy you a car or you can earn it on your own
- you’ll take, but doesn’t mean you’re not capable of working for it - have opp. to do that
Three classes of growth factors:
- Amino acids
- Purines and pyrimidines
- Vitamins
Three classes of growth factors:
- Amino acids
• 20 amino acids are needed for protein synthesis
- if you look at an Aa codon chart (there’s 20), so to be able to accommodate every codon that you encounter, you would need to have a total of 20 AA’s avail. in some copy #
(lego block - 20 diff colours/shapes etc. & then you make proteins which are lego castles)
Three classes of growth factors:
- Purines and pyrimidines
- A,G,T,CandU
- Needed to make NUCLEOTIDES, building blocks of DNA and RNA
(lego blocks that come for DNA in 4 flavours & RNA in 4 flavours & then you build nucleic acids (the castle))
Three classes of growth factors:
- Vitamins
- Small molecules used to make organic COFACTORS (usually something needed by an enzyme for full function)
- NON-protein components required by some enzymes (protein)
- Ex) Nicotinic acid –> NAD+
What is the cofactor usually made of?
NON-protein
What is the enzyme usually made of?
PROTEIN
Describe which is the cofactor and which is the vitamin
Ex) Nicotinic acid –> NAD+
Nicotinic acid - vitamin
NAD+ - cofactor (since this cofactor is ORGANIC its called a COENZYME)
- imp. cofactor that needs to be present for glycolysis & Kreb’s cycle
- necessity to have it
- inability to produce energy if the enzyme doesn’t have it & cell will die
Growth factor requirements
- Many have NO growth factor requirements
- Ex) E. coli
- Addition of growth factors to medium may promote growth
- Some bacteria require many
- Ex) Leuconostoc mesenteroides requires ALL 20 amino acids, 4 purines and pyrimidines, 10 different vitamins
Describe E. coli’s growth factor requirements
NO growth factor requirements
NOT picky –> don’t have to worry; can make what they req. by themselves
- can build things - will be AUTONOMOUS - do a lot of things SOLO (CAN COOK)
Describe Leuconostoc mesenteroides growth factor requirements
require MANY
requires ALL 20 amino acids, 4 purines and pyrimidines, 10 different vitamins
PICKY - can’t make it on their own (CAN’T COOK)
Describe PABA (p-aminobenzoic acid) growth factor
some bacteria use this pathway for folic acid syn.
FUNCTION: precursor of folic acid
- necessary by bacterium to form AA & some nucleotides
- if bacterium doesn’t have folic acid, it cannot form full spectrum of nucleotides & AA’s that it req’s & can normally do on its own
Describe Sulfa drug
antibiotic
- analogs to PABA (look like PABA, but isn’t), which confuses bacterium & allows it in
- PREVENT folic acid syn. which this is present in you
- therefore, bacterium can’t make the folic acid, AA, nucleotides
- antibiotic has PERFECT selective toxicity - b/c we don’t make folic acid, we get it from our diet, therefore when we take the drug it doesn’t interfere with our own folic acid syn. b/c we don’t do our own folic acid syn
- can be resistant
Describe Biotin growth factor
used in the formation of C-C cov. bonds
FUNCTION: fatty acid biosynthesis; some CO2 fixation rxns
Describe Nicotinic acid (Niacin)
FUNCTION: precursor to NAD+