Cellular Respiration U1

glycolysis (cytoplasm) citric acid cycle (matrix of the mitochondria) electron transport chain (inner membrane of the mitochondria)

when a phosphate group is added to a molecule (ADP + Pi —> ATP)

energy investment (2 ATP) energy payoff (4 ATP, 2 ATP net gain)

H ions are bound by dehydrogenase enzymes to become NADH, carry H ions and electrons to etc in the inner membrane of the mitochondria

remove hydrogen ions and electrons, pass H ions to NAD to become NADH

glucose molecule is broken down into 2 three carbon pyruvate molecules in to cytoplasm, this does not require oxygen

pyruvate is broken down into an acetyl group and CO2 is released each acetyl group combines with co enzyme A forming acetyl coenzyme A

the acetyl group from acetyl coA enters the citric acid cycle and combines with oxaloacetate to form citrate the citric acid cycle involves many enzyme controlled steps which results in the regeneration of oxaloacetate from citrate generating ATP in the process carbon is released in the form of CO2 (dehydrogenase enzymes)

oxygen (forms water)

H ions and electrons from NADH are passed to the ETC, reducing NADH to NAD electrons are passed along the ETC releasing energy this energy is used to pump H ions across the inner mitochondrial membrane these H ions then flow back through the membrane protein ATP synthase, which rotates, synthesising ATP oxygen combines with H ions and electrons to form water

fats, carbohydrates and proteins

C, H and O converted into glucose or intermediates in glycolytic pathway (glycolysis)

C, H and O glycerol and fatty acids glycerol converted into glycolytic intermediate fatty acids metabolised into molecular fragments that enter the pathway as acetyl coA for citric acid cycle

C, H, O, N and S broken down into amino acids by digestive enzymes excess amino acids undergo deanimation forming urea and intermediates intermediates enter metabolic pathway as substrates