A2 - Respiration Flashcards
process of glycolysis
1) glucose converted into phosphorylated glucose by hydrolysis of 2x ATP molecules to ADP (provides energy to activate glucose
and lowers AE for enzyme controlled reactions that follow)
2) Phosphorylated glucose split into 2X triose phosphate (3C molecule)
each triose phosphate oxidised (H removed from each of 2 triose phosphate and transferred to H carrier molecule AKA NAD > NADH
3) enzyme controlled reactions convert each triose phosphate into another 3C molecule (pyruvate) so 2 molecules of ATP are regenerated from ADP
importance of glycolysis
-to turn Glucose into pyruvate, so it can enter into the Krebs cycle to produce more energy and generate ATP (Energy) in the process.
-provides the cell with energy in the form of ATP and NADH. Pyruvate produced by glycolysis is further metabolised in the citric acid cycle and the electron transport chain, which allow the cell to produce even more ATP through oxidative phosphorylation.
What are the end products of glycolysis?
-net gain of 2 x ATP
-2 x reduced NAD (NADH)
-2 x pyruvate
Process of link reaction
-pyruvate molecule from glycolysis diffuses from cytoplasm across mitochondrial membrane into mitochondrial matrix
-pyruvate (3c) is oxidised (and decarboxylated) to acetate (2c molecule) so CO2 is produced as a by-product and the 2H lost from pyruvate is accepted by NAD>NADH to be used in ATP later on (in anaerobic resp)
-acetate combined with coenzyme A (CoA) to produce acetyl coenzyme A (2c molecule)
importance of links reaction
The Link Reaction is crucial in producing ATP, which is the energy currency of cells. Without the Link Reaction, cells would not be able to produce the energy needed for processes such as muscle contraction, ion transport, and DNA synthesis.
Process of kerbs cycle
-Takes place in mitochondrial matrix and involves a series of redox reactions
- acetyl CoA from link reaction combines with 4 c molecule, releasing coenzyme A and producing 6c molecule
-in a series of reactions, 6 c molecule loses co2 and H to give 4C molecule
-H+ being lost means coenzymes NAD and FAD are reduced
- 1ATP (adp +pi ) produced as a result of substrate level phosphorylation
-remaining 4c molecule is available t combine with new molecule of acetyl-co-enzyme A a to being cycle again
importance of krebs cycle
- It breaks down/oxidizes macromolecules into smaller ones (e.g. pyruvate into CO2)
- Produces H atoms which are carried by NAD to the electron transfer chain for oxidative phosphorylation, leading to the production of ATP thus providing metabolic energy for the cell.
- Regenerates the 4-carbon molecule that combines with acetyl CoA; without this, acetyl CoA would accumulate/build up.
- Source of intermediate compounds that is used for manufacturing other substances, like fatty acids and amino acids.
oxidative phosphorylation process
-occurs in the cristae
-NADH and FADH from kerbs, linked and glycolysis are oxidised to release H atoms and split into H+ and e-
-in a series of redox reactions, e- are transferred down e- transfer chain. as e- decrease in energy levels, energy is released
-energy that is released allows active transport of H+ across inner mitochondrial membrane into intermembranal space
-H+ diffuse by facilitated transport into matrix down electrochemical gradient via ATP synthase channel (embedded in inner mitochondrial membrane). so there’s a high conc of H+ in intermembrane space and lower conc in matrix
-releases energy to synthesise ATP from ADP + Pi
-in matrix, at the end of electron transport chain, oxygen is the final electron acceptor (e- can’t pass along otherwise), so protons, electrons and oxygen combine to form water
importance of oxidative phosphorylation
-To convert the energy of the electrons within the hydrogen atoms into a form that cells can use: ATP.
-it produces reactive oxygen species such as superoxide and hydrogen peroxide, which lead to propagation of free radicals which is necessary for the maturation process of cellular structures
Why Is Oxygen Important?
Because it acts as the final e- acceptor in the electron transfer chain; without it removing electrons at the end of the chain, the H+ ions and electrons would ‘back up’ (have nowhere to go) along the chain and respiration would stop.
