1.7- respiration Flashcards
what is the main substance broken down to release energy?
glucose
cellular respiration equation
glucose + oxygen —> carbon dioxide + water + energy (38 ATP)
3 stages of cellular respiration
glycolysis
citric acid cycle
electron transport chain
where does the citric acid cycle take place?
central matrix of the mitochondria
where does the electron transport chain take place?
inner mitochondrial membrane
what is glycolysis?
the breakdown of glucose to pyruvate in the cytoplasm
2 phases of glycolysis
energy investment phase- uses 2ATP
energy pay-off phase- generates 4ATP
what is required during the energy investment phase of glycolysis and why?
ATP required for the phosphorylation of glucose and intermediate molecules
what does the energy investment phase lead to and what does this result in?
the energy investment phase leads to the generation of more ATP molecules during the energy pay-off phase
results in a net gain of ATP molecules
3 steps of the energy pay-off phase
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 at the end of glycolysis if oxygen is present?
pyruvate broken down to an acetyl group that combines with coenzyme A forming acetyl coenzyme A
5 steps of the citric acid cycle
in aerobic conditions pyruvate is broken down to an acetyl group that combines with coenzyme A forming acetyl coenzyme A
acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate
in 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
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?
series of carrier proteins attached to the inner mitochondrial membrane
5 steps of the electron transport chain
electrons are passed along the electron transport chain releasing energy
this energy allows hydrogen ions to be pumped across the inner mitochondrial membrane
the flow of the ions back across the membrane synthesises ATP by a protein called ATP synthase
hydrogen ions and electrons combine with oxygen to form water
oxygen known as the final hydrogen acceptor
what is oxygen known as?
the final hydrogen acceptor
