CGP Respiration Flashcards
Where does glycolysis happen?
In the cytoplasm of cells.
Glycolysis is an __________ process.
Anaerobic process, as it doesn’t require oxygen.
What does glycolysis involve?
Splitting one molecule of glucose (with 6 carbons) into 2 smaller molecules of pyruvate (3C).
Outline the process of glycolysis.
- Glucose is phosphorylated using a phosphate from a molecule of ATP. This creates 1 molecule of ATP phosphate and 1 molecule of ADP.
- ATP is then used to add another phosphate, forming hexose biphosphate.
- Hexose biphosphate is then split into 2 molecules of triode phosphate.
- Triode phosphate is oxidised (loses hydrogen) forming 2 molecules of pyruvate.
- NAD collects the H+ ions, forming 2 NADH.
- Net gain of 2 ATP.
What happens in anaerobic respiration?
The pyruvate produced in glycolysis is converted into ethanol (plants) or lactate (animal cells) using NADH.
Why is lactate / ethanol produced?
The production regenerates oxidised NAD. This means glycolysis can continue, even when there isn’t much oxygen - so a small amount of ATP can still be produced.
Where does the link reaction occur?
Matrix of the mitochondria.
How are the two pyruvate molecules moved to the mitochondria?
They’re actively transported.
What happens in the link reaction?
- 1 carbon is removed from pyruvate in the form of CO2.
- Pyruvate is then oxidised to form acetate and NAD is reduced to form NADH.
- Acetate is combined with CoA to form acetyl CoA.
How many pyruvate molecules are used to make every glucose molecule?
Two
Where does the kerbs cycle occur?
Matrix of mitochondria
Outline the Krebs cycle.
- Acetyl CoA combines with a 4 carbon molecule to form a 6 carbon molecule. CoA then disappears back to link reaction.
- The 6C molecule is converted to 5C molecule.
- Decarboxylation occurs (CO2 removed).
- Dehydrogenation occurs (hydrogen removed).
- The hydrogen is used to produce NADH from NAD.
- The 5C is the converted into a 4C molecule.
- Decarboxylation and dehydrogenation occur, producing 1 molecule of FADH and 2 NADH.
- ATP produced by the direct transfer of a phosphate group from an intermediate compound to ADP. (Substrate level phosphorylation).
What is oxidative phosphorylation?
The process where the energy carried by electrons, from reduced coenzymes (NADH and FADH) is used to make ATP.
This involves the electron transport chain.
Outline how oxidative phosphorylation works.
- Hydrogen atoms are released from NADH and FADH as they’re oxidised to NAD and FAD. The H atoms split into protons and electrons.
- The electrons move down the electron transport chain, losing energy at each carrier.
- This energy is used by the electron carriers to pump protons from the mitochondrial matrix into the intermembrane space.
- The conc of protons is now higher in the intermembrane space than in the mitochondria matrix - forming a concentration gradient of ions.
- Protons then move down the electrochemical gradient, back across the mitochondrial membrane and into mitochondrial matrix, via ATPsynthase. This movement drives the synthesis of ADP and Pi to ATP.
- In the mitochondrial matrix, at the end of the transport chain, the protons, electrons and O2 (from blood) combine to form water.
What is oxygen called in oxidative phosphorylation?
The terminal electron acceptor.
