Topic6 Microbial Physiology Flashcards
What are the 2 cateogories of cellular metabolism?
where does the energy come from?
Where does the carbon come from?
What are phototrophs?
Obtaining energy from light
what are autotrophs?
Deriving carbon from CO2
What are heterotrophs?
Deriving carbon from organic compounds
Metabolism of prochlorococcus and spirulina is?
photoautotroph
Metabolism of Heliobacillus mobilis and Rhodobacter sphaeroides is?
photoheterotrophs
Can fermicute be photosynthetic? if so, ex?
Yes- Heliobacillus mobilis
What is chemoorganoheterotroph?
Deriving energy from chemical - organic chemical - deriving carbon from organic matter
Metabolism of e.coli?
Chemoorganoheterotroph
What is a chemotroph?
Deriving energy from chemicals
What is chemolithoautotroph?
what is another name for this?
Deriving energy from chemical- inorganic- fixing their own carbon from co2
lithotrophs
Aquifex, geobacter, and thiobacillus ferroxidans metabolism
chemolithoautotroph
What does aquifex oxidize? products/reactants
Hydrogen and oxygen yields water and energy
thiobacillus ferroxidans oxidize what?
sulfur and iron
sulfur oxidation yields
acid
Name 6 elements essential for all microorganisms
HCNOPS
oxygen found in what macromolecule, nitrogen in what, silicon, boron, phosphorous, etc.
oxygen : dna, rna, lipids, carbohydrates etc. in a cell
boron : signalling
silicon: build diatom- silica oxide around itself
phosphorous: phospholipid, backbone of dna and rna, majority in rna
nitrogen: protein, bases of nucleic acid,
Dicuss effect of replacing elements and give an example.
Some can be harmful, some can be harmless
tongston substituting molybdenum
Describe the effect of lead and why it can be harmful.
Lead can displace elements that should be there.
Name top 4 elements by dry weight in an organism
carbon, oxygen, nitrogen, hydrogen
50,20,12,8%
Name the top macromolecules in a cell
protein, rna, lipid,polysaccharide,lipopolysaccharide, dna
Where are the molecules needed to build up the macromolecules coming from?
they are intermediates of glycolysis and tca cycle
Is succinyl coa also used as building block?
yes
energy used to fuel synthesis of new cells from precursors is provided in the form of?
atp
What pathways are precursors made of in different cells?
Same pathways
Energy used to fuel precursor synthesis is?
ATP
Describe the amount of ATP required to synthesize new cell in different organisms
The amt of ATP is essentailly the same bc the pathways are the same.
Name 5 constraints on microbial growth and fitness
- It more or less takes same amt ATP to make a cell from the same starting substrate.
- cell yield is proportional to atp yield per mol of substrate
- Cells making more atp per mol substrate make more progeny per mol substrate
- cells making more progeny outcompete ones making fewer
- atp yield is a critical selective force.in microbial competition and evolution - RATE OF ATP SYNTHESIS IS ALSO CRITICAL
What is substrate level phosphorylation?
when a high energy substrate donates Pi directly to ADP to make ATP
Describe ATP as an energy storage
IT is not for long term energy storage - it is to pass energy. Fast production and usage - balance
What is alternative to SLP?
ATP production from ion gradient in energized membrane
Describe Electron transport-mediated phosphorylation
ATP is synthesized from ADP and Pi via ATP synthase with ion motive force created by the electron transport chain.
Describe energized membrane
More positive charge outside - proton or Na
Name 4 high energy compounds
phosphoenolpyruvate, ATP, acetyl-CoA, acetyl phosphate
Name a not as high energy compound
glucose-6-phosphate
Why is ATP high in energy?
It is a very strong acid, and the oxygens are charged -1, -1 and -2. The charges repell each other.
Why isn’t AMP as energetic?
The last bond is a standard ester bond, which is not as energetic as the anhydride bonds
What are the 12 major precursor molecules discussed?
Glucose 6 P
Fructose 6 P
Ribose 5 P
Triose phosphate
3-phosphoglycerate
phosphoenolpyruvate
pyruvate
acetyl coA
oxaloacetate
2oxoglutarate
succinyl CoA
Does glucose pass through the membrane?
No- they are polar
Describe the 3 transporters of the phototransferase system
- Simple transport- driven by proton motive force
- Group translocation - transported substance - chemical modification, driven by phosphoenolpyruvate=activated form of transported compound
- ABC transporter - periplasmic binding proteins involved, energy from ATP
ABC transporter means
ATP binding casette
One role of ABP transport in cells like e.coli is?
Determination of specificity of transporter for glucose for ex.
What does the phosphotransferase system do to accumulate things in the cell?
It puts some kind of charge on the substance, like phosphorylating glucose
Where is the phosphate coming from to phosphorylate glucose?
from PEP
Why does glucose keep going through the pore when it is acucumulated in the cell?
The concentration of unmodified glucose is low in the cell
What are the purposes of 2 rearrangements that occur during glycolysis?
- to allow cleavage by aldolase
- to make a high energy intermediate- the rearrangement is pulling the rxn
Free energy change of rxn depends on what?
concentration of products and reactants
What is the concentration of proton dealt with in biological system?
pH 7, which is 10^-7M proton
What does delta G tell you?
direction that a rxn wants to go
What does negative delta G mean?
wants to make product
Is cleavage of fructose1,6 bisphosphate favorable?
NO- more product than reactant
What enzyme links glycolysis and the tca cycle?
pyruvate dehydrogenase
Summarize the reaction carried out by tca cycle
It oxidizes acetyl coa into CO2.
It also provides ATP and cellular building blocks
What group of the CoA attaches to pyruvate?
the sulfhydril group
Acetyl coa is a good donor of what?
acetate
What are the 2 functions of TCA cycle?
- energy- oxidize acetate group to acetyl coa
- biosynthesis- intermediates are important biosynthetic precursors
how many times are you going through tca cycle per glucose?
2x bc you have 2 pyruvate, and 2 acetyl coa
Biosynthetic pathways are essentially _____ for all organisms
same
High energy bonds have what kind of group transfer potential?
high group transfer potential
PTS system saves _____ and are found in many what?
ATP, prokaryotes
At equilibrium, delta G is
zero
Why does PEP have high group transfer potential?
keto-enol tautomerization after transfer
Is oxygen involved in glucose oxidation to co2?
no
Through glycolysis, pdh, and tca cycle, how many co2, nadh, nadph, and fadh2 are produced? How many ATP?
6co2, 8nadh, 2nadph, and 2 fadh2
4 atp
Where is the rest of the energy not accounted for the atp production when comapred to the reaction delta G?
in the reduced cofactors
What does the electron tower display?
relative affinity of various carriers for e-
Electrons naturally flow from what to what potential? What kind of reactions are these?
from low to high potential. They are exergonic reactions
Endergonic reaction flow of electron is from what to what potential?
from high to low potential- it requires energy
What is the equation deltaG=-nFdeltaE showing?
relationship of electrical potential energy to chemical potential energy
F=96.48kJ/V
n=number of electrons
What is a rxn for oxidizing NADH?
1/2O2+NADH+H+ => H2O + NAD
What are the 2 Mitchell’s hypotheses?
I. Electron transport creates a proton gradient across the cell membrane
II. Energy stored in proton gradient is converted to ATP by ATP synthase
What is the net rxn of electron transport chain?
separating the electron from hydrogen, pushing protons out, and letting electron trickle down through electron carriers.
What is the unfavorable part of electron transport chain?
taking proton out of the cell, against the electrochemical gradient
What is an alternative way to get electron into the quinone pool? What is it coupled to?
oxidation of succinate to fumarate.
This is coupled to FAD cofactor
What is the goal of electron transport chain/overal result? how many protons are transported out of the cell?
reduction of oxygen, oxidation of nadh, transporting 10 protons out of the cell
What does NAD+ carry?
2 e=, 1 proton to become NADH
What does FMN carry?
2e-, 2 protons, to become FMNH2
How do you convert FMN to FAD?
attach adenine via ester linkage to FMN
What does ubiquinone carry?
2 electrons, 2 protons to become ubiquinol
where is the oxidized ubiquinone localized to in the cell? why?
membrane, because of its hydrophobic tail
What happens to reduced ubiquinol in the membrane?
It remians uncharged- soluble in the membrane
Heme and Fe/S cluster containing protein carry what?
only electrons
What do you do if you have a compound that is not as oxidizing as oxygen?
couple at earlier step of electorn transport chain= don’t have to pump as many protons to reoxidize nadh
rotation of waht subunit drives atp synthase?
gamma
