Respiration - Yr 2 Flashcards
Aerobic
Requires glucose, oxygen and produces carbon dioxide, water and up to 38 molecules of ATP (2 from glycolysis, 2 from Krebs cycle and up to 34 from oxidative phosphorylation).
Anaerobic
Releasing energy from glucose without oxygen (produces lactate in animals and ethanol and carbon dioxide in plants and fungi) and 2 molecules of ATP.
Glycolysis
First part of cellular respiration in which glucose is broken down (in the cytoplasm). The overall yield of glycolysis is 2 molecules of ATP, 2 molecules of reduced NAD and 2 molecules of pyruvate.
Phosphorylation
Process which makes glucose more reactive by adding 2 phosphate molecules.
Oxidation
Loss of electrons or loss of hydrogen or gain of oxygen with a substance. Happens to the two triose phosphate molecules in glycolysis when hydrogen is removed.
NAD
A hydrogen carrier molecule which is important throughout respiration.
FAD
A hydrogen carrier molecule which is important in the Krebs cycle.
Pyruvate
2 molecules of this are produced by glycolysis. If there is no oxygen present then it will be converted into either lactate or ethanol during anaerobic respiration. If oxygen is present it will be actively transported into the matrix of the mitochondria where it is oxidized to acetate.
Link reaction
Process linking Glycolysis to the Krebs Cycle (in the matrix of the mitochondria), where the 2 molecules of pyruvate are converted to CO2 and acetylcoenzyme A. 2 NAD molecules are reduced to form reduced NAD.
Pyruvate + NAD + CoA acetyl CoA + reduced NAD + CO2
Acetyl CoA
Formed in the link reaction when coenzyme A combines with acetate (2C).
Kreb’s Cycle
A series of aerobic biochemical reactions in the matrix of mitochondria of most eukaryotic cells by which energy is obtained through introducing acetylcoenzyme A into a cycle of oxidation-reduction reactions (in the matrix of the mitochondria). Acetyl CoA combines with a 4C molecule to produce a 6C molecule. This then loses 2 CO2 and hydrogen to give a 4C molecule and ATP due to substrate level phosphorylation. The 4C molecule then combines with acetyl CoA to continue the cycle. Per glucose molecule it produces 2 molecules of ATP and 6 reduced NAD and 2 reduced FAD.
2 acetyl CoA + 6NAD+ + 2FAD + 2ADP + 2H3PO4 4CO2 + 6 NADH + 6H+ + 2FADH2 + 2ATP
Substrate level phosphorylation
Happens in plant and animal cells when phosphate groups are transferred from donor molecules to ADP to form ATP.
Oxidative phosphorylation
The formation of ATP in the electron transport system of aerobic respiration. Happens in the mitochondria within the inner folded membrane (cristae). It involves the transfer of electrons down a series of electron carrier molecules which form an electron transfer chain.
Electron transfer chain
Use of electrons from the Krebs Cycle to synthesise ATP via a series of oxidation-reduction reactions. As electrons pass along a chain of electron transfer carrier molecules in a series of oxidation-reduction reactions, the electrons release energy which causes the active transport of protons across the inner mitochondrial membrane and into inter-membranal space. The oxygen is the final acceptor of electrons in the electron transfer chain.
ATP synthase
An enzyme which is embedded in the inner membrane of the mitochondria through which protons pass through and cause changes to the structure of the enzyme which then catalyses the combination of ADP with inorganic phosphate to form ATP.
