Energy Transformation Flashcards
Ch. 8, 9, 10
What is fermentation
A catabolic pathway of partial degradation for organic fuels in the absence of O2
What is aerobic respiration
Catabolic pathway that consumes O2 as a reactant along with organic fuel
What is anaerobic respiration
Respiration without O2
What is oxidation
The loss of an electron/H+ from a substance in a reaction
What is reduction
Addition of an electron/H+ to a substance in a reaction
What is a reducing agent
Electron donor
What is an oxidizing agent
Electron acceptor
Redox reactions that move closer to O2 release or gain energy
Release energy
When electrons are stripped from glucose, they are first passed to NAD+ forming NADH. What type of molecule are electron carriers
Coenzyme
What is dehydrogenase
An enzyme that can remove a pair of atoms (2e- & 2H+) and delivers them to NAD+
What is substrate-level phosphorylation
Formation of ATP during glycolysis and the Krebs cycle
How does the production of ATP during substrate-level phosphorylation differ than that produced during oxidative phosphorylation
An enzyme transfers a phosphate group from a substrate to ADP rather than using an inorganic phosphate in the surroundings
What happens during the energy investment phase of glycolysis
The cell spends 2 ATP as Ea to begin glycolysis
What happens during the energy payoff phase of glycolysis
4 ATP are produced by substrate-level phosphorylation
NAD+ is reduced to NADH
What is the net yield of ATP H2O, pyruvate, CO2, NADH, and FADH2 during glycolysis
2 ATP
2 H2O
2 pyruvate
2 NADH
0 FADH2
0 CO2
What are the 4 steps of the link reaction
- Pyruvate enters mitochondria via active transport
- Pyruvate’s carboxyl group is fully oxidized and given off as 1 CO2
- Remaining 2-C fragment is oxidized and e- transfers to NAD+, forming NADH
- CoA S atom attaches to the 2-C, forming Acetyl CoA
What is the Krebs cycle
Oxidization of pyruvate
What are the first steps of the citric acid cycle
Acetyl CoA adds the acetyl group to oxaloacetate, forming citrate which has high Ep. CoA-SH leaves.
What is the net yield of ATP, FADH2, NADH, & CO2 of glycolysis and the Krebs cycle
4 ATP
2 FADH2
10 NADH
4 CO2
What is a prosthetic group
Non-protein component (coenzyme/cofactor) bound to proteins in electron transport chain
Where is the ETC found
In the inner mitochondria membrane
What is the first step in the ETC
Electrons from NADH (2) are first transported to mc in complex 1 (FMN)
In which complex does FADH2 transport its electrons and why
Complex 2 because it has lower Ep than NADH
What is a cytochrome
Electron carrier in the 3rd and 4th complex (starts with “cyt”)
Describe the ETC in terms of electronegativity
Electrons from NADH and FADH2 move from less electronegative carriers to more electronegative carriers, releasing G
How does ATP synthase generate ATP
- H+ ions flow through stator from intermembrane space and then enter a binding site on rotor
- This binding causes shape change and rotation of rotor. Each H+ makes 1 full rotation before passing through second stator channel and entering matrix
- Rotor spinning causes rod spinning, which activates catalytic sites in the knob that produce ATP from ADP and Pi
How many H+ are transported from the mitochondria matrix to the intermembrane space for each NADH & FADH2
NADH = 3
FADH2 = 2
What are 3 reasons the calculated number of ATP may differ from the total produced
- Phosphorylation/redox reactions may not be coupled properly
- e- may accidentally be transferred to FAD rather than NAD+
- Proton-motive force E may be used to drive other cell work rather than be used to produce ATP
What is the proton-motive force
H+ gradient between mitochondria membrane with the capacity for the gradient perform work
What is the difference between anaerobic respiration and fermentation
Anaerobic respiration uses an ETC, just with a different final electron receptor. Fermentation occurs without O2
By what method does fermentation produce ATP
Substrate-level phosphorylation
What are the 2 parts to fermentation
- Glycolysis
- NAD+ regeneration
What are the 2 steps to alcohol fermentation
- CO2 is released from pyruvate and pyruvate becomes acetaldehyde
- Acetaldehyde is reduced by NADH to ethanol, regenerating NAD+
What is the 1 step in lactic acid fermentation
Pyruvate is reduced by NADH to form lactate, regenerating NAD+ (no CO2)
What is an obligate anaerobe
Organism that does only fermentation and cannot survive in O2 rich environment
What is a falcultative anaerobe
Organism that can survive on fermentation or respiration
Eg. Muscle cells
For proteins to be used as fuel, they must first be digested into their
Amino acids
True or false: amino acid must be in excess to be used as fuel
True
Before amino acids can be used as fuel which group must be removed: carboxyl or amine
Amine group
What is beta oxidation
(Fats can become fuel through this process)
The breakdown of a fatty acid down to 2-C fragments that can be joined by a CoA to form acetyl CoA
