Cellular Respiration Flashcards
What is cellular respiration?
The release of energy from food molecules in cells.
What is the first stage of cellular respiration?
Glycolysis.
What happens during glycolysis?
Glucose is broken down into pyruvate in the cytoplasm of cells.
Intermediates of glycolysis are phosphorylated by ATP during the energy investment phase.
ATP is generated in glycolysis by the addition of inorganic phosphate (Pi) to ADP in an energy pay-off phase.
What is Phosphofructokinase (PFK)?
An enzyme that catalyses the irreversible transfer of a phosphate (Pi) from ATP to fructose-6-phosphate in glycolysis.
PFK is the key regulatory enzyme for glycolysis and when ATO and citrate levels are high in the cell, the cell no longer needs metabolic energy production to occur and PFK’s activity is inherited.
Give an account of the Citric Acid Cycle.
The citric acid cycle occurs in the matrix of the mitochondria
In the presence of oxygen pyruvate is broken down to an acetyl group.
An acetyl group combines with coenzyme A to be transferred to the citric acid cycle as acetyl coenzyme A.
What happens in the citric acid cycle after acetyl coenzyme A is produced?
Acetyl CoA combines with oxaloacetate to form citrate.
Some ATP is generated during the citric acid cycle.
Carbon Dioxide is released during the citric acid cycle.
What is the role of Dehydrogenase during glycolysis/the citric acid cycle?
Dehydrogenase removes hydrogen ions (H+) and electrons from intermediates and passes them on to coenzymes NAD and FAD to form NADH and FADH2.
What happens during the electron transport chain stage of cellular respiration?
Hydrogen ions and electrons are released by NADH and FADH2 to the electron transport chain in inner mitochondrial membranes.
High energy electron are used to pump hydrogen ions across a mitochondrial membrane.
What happens after hydrogen ions are pumped through the mitochondrial membrane during the electron transport chain?
The return flow of hydrogen ions through the inner mitochondrial membrane drives the enzyme ATP Synthase, synthesising ATP.
The final electron acceptor is oxygen which combines with hydrogen ions and electrons to form water.
What is the electron transport chain?
A collection of proteins called electron acceptors attached to a membrane.
What happens in the absence of oxygen?
The pyruvate produced by glycolysis follows a fermentation pathway.
Other than glucose, what alternative respiratory substrates can be used during respiration?
Starch, glycogen, other sugars, amino acids and fats.
