Microbial Metabolism Flashcards
What is metabolism?
All chemical reactions in organisms
What does catabolism do?
Produces ATP by breaking bonds (carbs, lipids, proteins, DNA, RNA)
What does anabolism do?
Uses ATP- monosaccharides, nucleotides, sugars, fatty acids, amino acids, atoms, ions
What happens when molecules are moving continuously?
A collision happens
What does the energy in collisions do?
Can disrupt electrons which break and form bonds
What is activation energy?
Energy needed to disrupt electrons
What is a reaction rate?
How often collisions occur
How can reaction rates be increased?
Increasing temperature or pressure
Enzymes
What does it mean when enzymes catalyze?
They speed up chemical reactions by lowering activation energy
What is a principle of enzymes related to chemical reactions?
They are not altered during them
What is an apoenzyme?
Protein part
What is a cofactor?
Non protein parts
What is a non protein part?
1 part Organic (coenzymes), carbon based—— NAD
1 part inorganic (ions), calcium, zinc, NO CARBON
What is a holoenzyme?
Fully functional unit
What is an induced fit?
The substrate is oriented in optimal position
What does an induced fit lead to?
Lower requirement of energy to initiate a chemical reaction
What are the enzyme mechanisms of reaction?
Specific substrate contacts enzyme active site
Induced fit
Substrate transforms
Products are released
Enzyme is UNCHANGED
What is vMax?
Maximum velocity
Enzymes are saturated (all active sites occupied)
Will not increase until more enzymes are added
What raises reaction rate up to a point?
Substrate concentration
What does temperature do to enzyme activity?
It denatures the protein
Bonds are broken and the protein is no longer functional
What happens to proteins at low temperatures?
It doesn’t denature, just freezes
What pH is optimal for most enzymes?
7
What happens when an enzyme pH is too high or too low?
It denatures
What are competitive inhibitors?
They compete for active sites
What do non-competitive inhibitors do?
They DO NOT bind to the active site
They bind to an allosteric site which changes the active site shape
Enzyme can no longer act on the substrate
What is feedback inhibition?
Non-competitive inhibitory pathway
Occurs in metabolism
How does feedback inhibition end?
End product binds to allosteric site in first enzyme so that the first enzyme can’t bind more substrates
What does the movement of electrons do?
Release energy!
What is a redox reaction?
Transfer of electrons via 1 or many from one reactant to another
What is oxidation?
Loss of electrons (LEO- loss electrons oxidation)
What is reduction?
Gain of electrons (GER- gain electrons reduction)
What is another name for a redox reaction?
Dehydrogenation- proton (H+) goes with electron= loss of H atom
How can you tell if a redox reaction has occurred?
Follow the H’s
What do molecules with lots of H’s have?
Lots of potential energy
What is phosphorylation?
Addition of a phosphate to a molecule (ADP to ATP)
What is substrate level phosphorylation?
The phosphate of a substrate is given to ADP via a catabolic reaction done by the enzyme
What is photophosphorylation?
Electrons come from the chlorophyll becoming excited by light
Received by the electron transport chain and energy is released
Proton pumps use released energy to create a proton gradient
Proton gradient turns ATP synthase and synthase makes ATP
What is oxidative phosphorylation?
Electrons are received from reduced carriers (organic molecules that contain H+ that are stripped from them by redox reactions- in metabolism)
Proton gradient and ATP synthase cycle occurs
Where does photophosphorylation occur in eukaryotes and prokaryotes?
Euks- chloroplasts
Proks- plasma membrane
Where does oxidative phosphorylation occur in eukaryotes and prokaryotes?
Euks- mitochondria
Proks- plasma membrane
What is an organic cofactor called?
Coenzyme
What is an inorganic cofactor called?
Ion
What are the 2 types of glucose catabolism?
cellular respiration and fermentation
What is cellular respiration?
complete breakdown to CO2 and H2O
What is the final electron acceptor for aerobic respiration?
oxygen
How is anaerobic respiration different from aerobic respiration?
final electron acceptor not O2
produces less energy
What are the stages of cellular respiration?
Glycolysis, synthesis of Acetyl-CoA, Krebs cycle, electron transport cycle
Where does glycolysis occur in euks and proks?
euks- cytoplasm
proks- cyotplasm
Where does synthesis of Acetyl-CoA occur in euks and proks?
euks- mitochondrial matrix
proks- cytoplasm
Where does Krebs cycle occur in euks and proks?
euks- mitochondrial matrix
proks- cytoplasm
Where does the electron transport chain occur in euks and proks?
euks- mitochondrial inner membrane
proks- plasma membrane
What is fermentation?
partial breakdown of glucose to organic waste product- produces lactic acid and alcohol
What happens during glycolysis?
-energy is released during this process by stripping glucose of all of the hydrogen molecules to make ATP
What are the products of glycolosis?
2 NADH, 2 ATP, 2 pyruvic acid
What does glycolysis mean?
splitting glucose
involves redox
What are the steps of glycolysis?
1 glucose oxidized to 2 pyruvic acid
2 NAD+ reduced to NADH (electron carrier)
2 ADP to ATP (substrate-level phosphorylation)
What happens during Acetyl-CoA formation?
Redox reaction
Pyruvic acid is oxidized to Acetyl-CoA
NAD+ is reduced to NADH
CO2 removed (decarboxylation)
What are the products of Acetyl-CoA formation?
2 NADH, 2 CO2, 2 Acetyl-CoA
What happens during the Krebs cycle?
redox reaction
intermediates are oxidized
NAD+ and FAD are reduced to NADH and FADH
CO2 removed (decarboxylation)
Substrate level phosphorylation (ADP to ATP)
What are the products of the Krebs cycle?
6 NADH, 2 FADH2, 2 ATP, & 4 CO2
What happens during the electron transport chain?
ETC receives electrons from electron carriers that are carrying electrons from glucose (NADH, FADH2)
NADH and FADH2 are oxidized and electrons go down the ETC
The final electron acceptor is oxygen, and oxygen becomes water
What is chemiosmosis?
Hydrogen diffusing through the ATP synthase
How does ATP synthase make ATP?
oxidative phosphorylation
How much ATP does cellular respiration produce in prokaryotes?
38 ATP
2 ATP from glycolysis
2 ATP from the Kreb’s cycle
34 ATP ETC
How much ATP does cellular respiration produce in eukaryotes?
36 ATP
2 ATP from glycolysis
2 ATP from the Kreb’s cycle
32 ATP ETC
Why do eukaryotes produce less ATP than prokaryotes?
NADH produced from glycolysis need ATP to move across the mitochondrial membrane for the ETC chain, 2 ATP are needed for that
What does fermentation do with NAD+?
recycles NAD which is a vital element for glycolysis
What happens during fermentation?
Involves redox
2 NADH are oxidized (H electrons are given to pyruvic acid)
2 pyruvic acids are reduced to organic waste products (lactic acid and ethanol)
What are the 2 major types of glucose fermentation?
lactic acid and alcohol
What happens during lactic acid fermentation? What is an example of lactic acid fermentation?
Pyruvic acid is reduced to lactic acid
Bacteria— milk—- cheese and yogurt
What happens during alcohol fermentation?
Acetaldehyde is reduced to ethanol
What is an example of alcohol fermentation?
yeast—- grape juice—- wine
What are the steps to lactic acid fermentation?
1 glucose
2 NAD are reduced to NADH
2 ADP to 2 ATP (substrate-level phosphorylation)
2 NADH oxidized to 2 NAD
2 pyruvic acid reduced to lactic acid
What are the steps to alcohol fermentation?
-2 NAD to 2 NADH (reduction)
-2 ADP to 2 ATP (substrate-level phosphorylation)
-2 pyruvic acid (first product)
-2 released CO2 produces 2 Acetaldehyde
Reduced to ethanol by 2 NADH to 2 NAD (NADH is oxidized)
