Unit 2 - KA 2: Cellular Respiration Flashcards
Describe the importance of ATP in metabollic pathways.
ATP allows the transfer of chemical energy from one reaction to another in a living cell.
Describe phosphorylation.
Phosphorylation is an enzyme controlled process where a phosphate group is added to a molecule, often reducing ATP to ADP + Pi. this often makes it more reactive.
Describe the first stage of respiration.
Glycolisis is the breakdown of Glucose to the final product of 2 Pyruvate. this occurs in the cytoplasm.
Energy investment phase:- Glucose -phosphorylation-> Intermediate 1 –> intermediate 2 -phosphorylation-> intermediate 3.
Energy payoff phase:- Intermediate 3 -(2NAD->2NADH)-(2ADP+pi->2ATP)-(2ADp+Pi->2ATP)->2 Pyruvate.
Describe the phases of glycolisis’ names.
Energy investment- 2 ATP is put into this process.
Energy Payoff- 4 ATP is produced, meaning there is a total net gain of 2 ATP.
What happens to the Hydrogen ions and electrons.
Dehydrogenase is an enzyme that removes Hydrogen ions and electrons from the substrate and passes them to NAD which becomes NADH and carries them to the final stage of aerobic respiration.
Describe the second stage of respiration.
The citric acid cycle occurs in the matrix of the mitochondria.
Pyruvate-(NAD->NADH)(CO₂)->Acetyl group–> Acetyl coenzyme A (⇌Coenzyme A) –> 𝄆 Citrate -(CO₂)-(4NAD->4NADH)-(2ADP+Pi–>2ATP) -Oxaloacetate𝄇
What must be present for pyruvate to be broken down into an acetyl group?
Oxygen
What are the 2 products of the citric acid cycle?
CO₂ and ATP
Describe the final stage of aerobic respiration
The Electron transport chain consists of a series of carrier protein molecules that are located on the inner mitochondrial membrane.
NADH releases hydrogen ions and high energy electrons.
The flowing electrons release energy allowing the protein pumps to pump the hydrogen ions across the membrane.
Hydrogen ions flow back across the membrane through the ATP synthase, allowing it to synthesise ATP (APD + Pi –> ATP).
OXygen is the final hydrogen and electron acceptor and forms water.
Define fermentation.
Fermentation is the partial breakdown of sugar in the absence of oxygen.
What process does fermentation begin with?
Glycolosis
Describe fermentation in Animals.
Pyruvate is converted into lactate. This process is reversible so aerobic respiration can occur once oxygen becomes available. Occurs in the cytoplasm.
Describe fermentation in Plants and Yeast cells.
Pyruvate is converted into ethanol and CO₂ (non-reversible). Occurs in the cytoplasm.
Why is aerobic respiration more efficient than fermentation?
As 38 ATP are produced during aerobic respiration compared to the 2 produced during fermentation.
