cellular respiration 1.7 Flashcards
what is cellular respiration
the breakdown of glucose to release energy
what does the energy from respiration do
build up ADP + Pi into ATP and breakdown ATP into ADP + Pi to release that energy when required
examples where ATP is needed
muscle contractions, DNA replication, protein synthesis, active transport, mitosis
phosphorylation
enzyme controlled process by which a phosphate group (and energy) from a molecule of ATP is added to a reactant molecule to make it more reactive
the three stages of cellular respiration
stage 1 glycolysis
stage 2 citric acid cycle
stage 3 electron transport chain
where does glycolysis take place in the cell
cytoplasm
where does the citric acid cycle take place in the cell
central matrix of the mitochondria
where does electron transport chain take place in the cell
the inner membranes of the mitochondria
glycolysis
-glycolysis is a series of enzyme controlled reactions that take place in the cytoplasm
-it is the breakdown of glucose to pyruvate in the absence of oxygen
the two stages of glycolysis
energy investment phase and the energy payoff phase
glycolysis energy investment phase
2 molecules of ATP are used for the phosphorylation of glucose and intermediates
glycolysis energy payoff phase
4 molecules of ATP are produced and dehydrogenase enzymes remove H+ ions and high energy electrons from respiratory substrates and passes them onto the coenzyme NAD to form NADH
critic acid cycle
-in aerobic conditions pyruvate is broken down into carbon dioxide and an acetyl group
-the acetyl group combines with coenzyme A to form acetyl coenzyme A and is transferred to the citric acid cycle
-the acetyl group of 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 1 ATP and releases 2 carbon dioxide molecules
-dehydrogenase enzymes remove H+ ions and high energy electrons from respiratory substrates and passes them onto the coenzyme NAD to form NADH
electron transport chain
-series of carrier proteins attached to inner mitochondrial membrane
-the H+ and electrons from NADH produced during glycolysis and the citric acid cycle are passed to the electron transport chain on the inner mitochondrial membrane
-the high energy electrons are passed along the chain releasing their energy
-this energy is used to actively pump H+ ions across the inner mitochondrial membrane from the matrix to the inter membrane space
-the return flow of H+ ions back through the membrane, protein ATP synthase causes it to rotate and catalyse the synthesis of ATP from ADP + Pi
-finally H+ ions and electrons combine with oxygen (final electron acceptor) to form water
how many ATP are formed in cellular respiration
38 ATP molecules
