Aerobic Respiration Flashcards
GLYCOLYSIS: Where does it occur?
In the CYTOPLASM of cells.
GLYCOLYSIS: What are the stages?
- PHOSPHORYLATION: Glucose (6C) is phosphorylated by adding 2 phosphates (Pi) from 2 x ATP. This creates 2x triose phosphate (3C) and 2x ADP.
- OXIDATION: TP is oxidised forming 2x pyruvate (3C). 2x NAD -> 2x rNAD. 4ATP produced but net gain is 2ATP.
GLYCOLYSIS: How much ATP is produced overall?
2
GLYCOLYSIS: What happens to all the products in glycolysis?
2x of reduced NAD go to oxidative phosphorylation. 2x pyruvate molecules go to MATRIX of mitochondria for the LINK REACTION.
LINK REACTION: What are the stages of the link reaction?
Pyruvate (3C) is decarboxylated (carbon is removed). 1C removed to form CO2. NAD is reduced and pyruvate is converted to acetate (2C). Acetate is combination of coenzyme A (acetyl CoA). No ATP is produced.
LINK REACTION: How much ATP is produced?
0
LINK REACTION: How many times does the link reaction occur for every glucose molecule?
Two pyruvate molecules are made for every glucose molecule that enters glysolysis. This means that the link reaction happens twice so for each glucose molecule: 2 aceytle CoA goes to the Krebs cycle, 2x CO2 produced and 2x rNAD produced.
KREBS CYCLE: Where does it occur?
In the matrix of the mitochondria.
KREBS CYCLE: What is the first stage?
- Acetyl CoA (2C) from link reaction combines with oxaloacetate (4C) to form citrate.
- Coenzyme A goes back to link reaction to be reused.
KREBS CYCLE: What is the second stage?
- 6C citrate molecule is converted to a 5C molecule. Decarboxylation and dehydrogenation occurs.
- Hydrogen is used to produce reduced NAD from NAD.
KREBS CYCLE: What is the third stage?
- 5C converted to 4C molecule.
- Decarboxylation & dehydrogenation occur, producing 1x reduced FAD & 2x reduced NAD.
- ATP made by direct transfer of a phosphate group from an intermediate compound to ADP by substrate-level phosphoylation. Citrate now converted to oxaloacetate.
KREBS CYCLE: How many times does the Krebs cycle occur for each molecule of glucose?
Twice.
KREBS CYCLE: What products of the Krebs cycle are used and which are used in oxidative phosphorylation?
- 1 CoA reused in link - Oxaloacetate: regenerated for reuse in KC - 2xCO2: released as waste prod. - 1x ATP: Used for energy - 3x rNAD and 1x rFAD: To oxidative phosphorylation
OXIDATIVE PHOSPHORYLATION: What is and happens in oxidative phosphorylation?
It’s a process where the energy carried by electrons from reduced NAD and FAD is used to make ATP. Oxidative Phosphorylation involves two steps: the electron transport chain and chemiosmosis.
OXIDATIVE PHOSPHORYLATION: Stage 1 - Describe the steps in the electron transport chain (ETC).
- H atoms are released from rNAD and rFAD as theyre oxidised to NAD & FAD. H splits to H+ and e-.
- Electrons move along ETC (made up of 3 electron carriers) via series of redox reactions, losing energy at each carrier.
- This energy used by electron carriers to pump H+ from matrix into intermembrane space. Conc. of H+ now higher in intermembrane space than mitochondrial matrix - this forms electrochemical gradient.
