1.7 Flashcards
What is cellular respiration?
Cell respiration is a vital process which occurs in all living cells. It is made up of a series of enzyme controlled reactions making up a metabolic pathway which is responsible for generating a source of energy. The main substance which is broken down to release energy is glucose.
What is glycolysis?
Glycolysis is the breakdown of glucose to pyruvate in the cytoplasm. ATP is required for the phosphorylation of glucose and intermediates during the “energy investment phase” of glycolysis.
This leads to the generation of more ATP molecules during the “energy pay-off” phase. This results in a net gain of ATP molecules. Hydrogen ions and electrons are removed by a dehydrogenase enzyme. These hydrogen ions are picked up by NAD to form NADH.
The hydrogen ions and electrons from NADH are passed to the electron transport chain on the inner mitochondrial membrane.
What happens in aerobic conditions for glycolysis?
pyruvate is broken down to an acetyl group that combines with coenzyme A forming acetyl coenzyme A.
What is the citric acid cycle?
In the citric acid cycle the acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate. During a series of enzyme-controlled steps, citrate is gradually converted back into oxaloacetate which results in the generation of ATP and release of carbon dioxide.The citric acid cycle occurs in the matrix of the mitochondria.
Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to NAD forming NADH. Hydrogen ions and electrons from NADH are passed to the electron transport chain on the inner mitochondrial membrane.
What is the electron transport chain?
Electrons are passed along the electron transport chain (series of carrier proteins attached to the inner mitochondrial membrane) releasing energy. This energy allows hydrogen ions to be pumped across the inner mitochondrial membrane. The flow of these ions back through the membrane protein ATP synthase results in the production of ATP.
What is the final hydrogen acceptor?
Finally, hydrogen ions and electrons combine with oxygen to form water. Therefore, oxygen is known as the final hydrogen acceptor.
What is ATP?
ATP (Adenosine Triphosphate) is the molecule that cells use to; capture, store and transport free energy in chemical form. It is synthesised in a reversible reaction from ADP and Pi.
ATP is used to transfer energy to cellular processes which require energy. It is the universal link between anabolic and catabolic pathways.
Examples of cellular processes
protein synthesis, mitosis, nerve impulse transmission and muscle cell contraction.
