Microbial Metabolism - Chapter 4 Flashcards
Catabolism
Large moelcules being broken into smaller molecules
Is catabolism energetically favorable or unfavorable?
Energetically favorable as it releases energy
Anabolism
Small molecules are assembled into larger molecules
Is anabolism energetically favorable or unfavorable?
Energetically unfavorable as it uses energy
What is metabolism a combination of?
Catabolism and anabolism
What do chemotrophs use as their energy source?
Chemicals
What do phototrophs use as their energy source?
Light
What do autotrophs use as their carbon source?
Inorganic compounds, most likely CO2
What do heterotrophs use as their carbon source?
Organic compounds
What can chemotrophs be further divided into?
Autotrophs or heterotrophs
What can phototrophs be further divided into?
Autotrophs or heterotrophs
What kind of energy do bacteria use?
Any type, they can be chemoautotrophs, chemoheterotrophs, photoautotrophs, or photoheterotrophs
Donor
Lose an electron, give an electron away
Acceptor
Gain an electron
Are donors oxidized or reduced?
Oxidized
Are acceptors oxidized or reduced?
Reduced
Donor Agent
Reducing agent
Reducing Agent
Reduces the other molecule
Acceptor Agent
Oxidizing agent
Oxidizing Agent
Oxidizes the other molecule
What happens to hydrogen in the oxidized form?
Hydrogen is taken away
How does the cell make the most of its ATP?
Through storing the energy in moelcules and putting them through the electron transport chain
In what form is energy stored?
In the reduced form
What are energy storage types in the reduced form?
NADH, NADPH, or FADH2
Coupling Endergonic and Exergonic Reactions
ATP circles between ADP and ATP during metabolism
Phosphorylation
ADP -> ATP
Dephosphorylation
ATP -> ADP
Phosphorylation Energy Type
Solar or chemical energy
Dephosphorylation Energy Type
Energy available for cellular work including anabolism
What pathway can photosynthesis lead to?
The electron transport chain or glycolysis
Light Reaction
Photosynthesis -> electron transport chain
Dark Reaction
Photosynthesis -> glycolysis
What pathway can glycolysis lead to?
Transition reaction or fermentation
What pathway can fermentation lead to?
Electron transport chain
What pathway can the transition reaction lead to?
Kreb’s cycle which then leads to the electron transport chain
Glycolysis
Catabolism of carbohydrates
What is the first step of glycolysis?
Break down glucose into 2, 3 carbon molecules and add a phosphate from ATP.
Phosphorylate molecules
How much ATP does the first step of glycolysis use?
2 ATP
What is the second step of glycolysis?
Convert the molecule into pyruvate by taking the phosphate away, making NADH
How much ATP does the second step of glycolysis produce?
4 ATP
What is the amount of ATP produced during glycolysis?
2 ATP (4 gained, 2 used)
Glycolysis Steps
Energy investment phase and energy payoff phase
Oxidative Phosphorylation
Remove phosphate from the molecule (pyruvate + phosphate) and add to ADP to make ATP
What needs to happen for pyruvate to get into the appropriate form for the Krebs cycle?
A carbon from pyruvate needs to be removed to make an acetyl and the acetyl has to be added to coenzyme A to make Acetyl CoA
What molecule goes into the Krebs cycle instead of pyruvate?
Acetyl CoA
Transition Reaction
Pyruvate -> Acetyl -> Acetyl CoA
Krebs Cycle Reactions
It is both anabolic and catabolic to create energy
Krebs Cycle
Acetyl CoA -> breaks it down -> builds it back up
What kind of loop is the Krebs cycle?
Closed loop
Closed Loop
Last step regenerates the starting product
What are the products made per Acetyl CoA?
1 ATP/GTP, 3 NADH, 1 FADH2
How much Acetyl CoA comes from glycolysis into the Krebs Cycle?
2 Acetyl CoA
Krebs Cycle Products
2 ATP/GTP, 6 NADH, 2 FADH2
What other products can be made from the other cycles the Krebs cycle can feed into?
Amino acids, nucleotides, lipids (fatty acids and sterols), and additional moelcules (porphyrins, heme, and chlorophyll)
Where does oxidative phosphorylation occur in a prokaryote?
Plasma membrane
Where does oxidative phosphorylation occur in a eukaryote?
Inner mitochondria membrane
Prokaryote Oxidative Phosphorylation
Hydrogen ions flow from the cytoplasm to the periplasmic space
Eukaryote Oxidative Phosphorylation
Hydrogen ions flow from the matrix to the intermembrane space
Electron Transport Chain
Remove hydrogen ions from energy carries, put them through channels to flow into the periplasmic space, then pump across the membrane, and pump it back through ATP synthase through the creation of a high concentration of hydrogen ions
Where is there a high concentration of hydrogen in the electron transport chain?
Outside, periplasmic space
What does the final electron acceptor use and make in aerobic respiration?
It uses oxygen and makes water
What does ATP Synthase create?
ATP when it comes back in
Chemiosmosis
Process of moving the hydrogen atoms as if they’re water
What organisms do respiration without oxygen?
Bacteria or archaea
What is the electron acceptor in anaerobic respiration?
An inorganic compound, likely a sulfur compound
What does anaerobic respiration make?
If a sulfur compound it makes H2S
How much ATP per NADH in the electron transport system?
3 ATP
How much ATP per FADH2 in the electron transport system?
2 ATP
What is the theoretical max of ATP for aerobic respiration?
38 ATP, most efficient
Theoretical max ATP from glycolysis
8 ATP
Theoretical max ATP from the transition reaction
6 ATP
Theoretical max ATP from the Krebs cycle
24 ATP
What does fermentation start with?
The glycolysis reaction and it puts it into other fermentation reactions
Fermentation Products
Acids and alcohols
Fermentation Reaction Types
Lactic acid and alcohol
What can be used to determine if fermentation occurs in lab?
We can use different types of sugar in media that have a pH indicator to determine if they have gone through fermentation
What color does the phenol turn if fermentation occurs?
Red to yellow
How do we know if CO2 has been produced in lab?
Gas bubbles will be produced in the Durham tube
What can fermentation make?
Commercial solvents, food, pharmaceuticals, etc.
What other organisms can do fermentation?
Yeasts
Is anaerobic respiration efficient?
It can be depending on the inorganic compound used
Anaerobic Respiration Theoretical Yield ATP
5-36 ATP
Fermentation Theoretical Yield ATP
2 ATP
Does fermentation make its own ATP?
No, it comes from the electron transport system
What metabolism is best for bacteria?
Each one has different benefits depending on the environment the microbe is in