respiration Flashcards
(33 cards)
define respiration
the process whereby organic molecules are oxidised to release chemical potential energy for the synthesis of ATP
what are the 2 methods of ATP synthesis?
substrate-level phosphorylation and oxidative phosphorylation
function of coenzymes NAD+ and FAD+
act as electron acceptors and donors that transfer electrons from substrates to ETC
what is the structure-function relationship of the inner mitochondrial membrane?
the inner mitochondrial membrane is extensively folded into cristae projecting inwards towards the matrix=> providing a large surface area for the attachment of electron carriers, enzymes and ATP synthase
site of accumulation of H+
intermembrane space
direction of diffusion of H+
from intermembrane space to the matrix
site of glycolysis
cytosol
outline the process of glycolysis
- phosphorylation of hexose
->glucose is phosphorylated by ATP into glucose-6-phosphate
->glucose-6-phosphate is converted into fructose-6-phosphate
->fructose-6-phosphate is phosphorylated by ATP into fructose-1,6-bisphosphate - cleavage of 6C sugar bisphosphate
->fructose-1,6-bisphosphate is cleaved into 2 triose phosphate molecules (3C)
3.triose phosphates are converted into pyruvate
->oxidation occurs and 2 NADH are synthesized
->substrate-level phosphorylation also occurs producing 4 ATP
-> net 2 ATP produced
requirements for glycolysis (reactants)
1 glucose, 4 ADP, 2 NAD+
products of glycolysis
2 pyruvate, 2 ATP, 2 NADH
name the enzyme which catlayzes the phosphorylation of glucose into glucose-6-phosphate
hexokinase
hexokinase is allosterically inhibited by…
its product glucose-6-phosphate
name the enzyme which catalyzes the phosphorylation of fructose-6-phosphate into fructose-1,6-bisphosphate
phosphofructokinase (PFK1)
PFK1 is allosterically inhibited by…
ATP
outline the process of link reaction
1.pyruvate is decarboxylated releasing one CO2 this is catalysed by pyruvate decarboxylase
2. NAD+ is reduced to NADH
3. the remaining 2C compound combines with coenzyme A to form acetyl-CoA
site of link reaction
matrix of the mitochondria
requirements of link reaction (reactants)?
2 pyruvate, 2 NAD+, 2 coenzyme A
products of link reaction?
2 acetyl CoA, 2 NADH, 2CO2
outline the process of the Krebs cycle
- acetyl-CoA combines with oxaloacetate to form citrate
- citrate undergoes oxidative decarboxylation to form a-ketoglutarate
-> 1 NAD+ is reduced to NADH
-> 1CO2 is released
3.a-ketoglutarate undergoes oxidative decarboxylation to form succinyl CoA
-> 1 NAD+ is reduced to NADH
-> 1CO2 is released - succinyl CoA undergoes substrate-level phosphorylation to form succinate
-> 1 ATP is produced - succinate is oxidised into malatate
-> 1 FADH+ is reduced to FADH2
6.malatate is oxidised and rearrranged to regenerate oxaloacetate
-> 1NAD+ is reduced to NADH
requirements for Krebs cycle (reactants) for one molecule of glucose?
2 acetyl-CoA, 6NAD+, 2 FAD+, 1 ADP
products of the Krebs cycle?
2 oxaloacetate, 4CO2, 6NADH, 2FADH2, 2ATP
what are the components in Krebs cycle? (total 7)
acetyl-CoA + oxaloacetate-> citrate->a-ketoglutarate->succinyl-CoA-> succinate-> malatate->regenerates oxaloacetate
how many turns of the Krebs cycle per glucose molecule?
2 turns-> 2 pyruvate required-> 2 oxaloacetate
outline the process of oxidative phosphorylation
- NADH and FADH2 donate electrons to electron carriers of ETC
2.electrons are passed down electron carriers of decreasing energy levels - electrons are then passed down to the final electron acceptor O2 (to form water)
- energy released from the flow of electrons is used to pump H+ from the matrix into the intermembrane space
- this creates a steep proton gradient as the inner membrane of the mitochondria is impermeable to ions resulting in the accumulation of H+ in the intermembrane space
6.diffusion of H+ from the intermembrane space into the matrix down a concentration gradient via the hydrophilic channel of ATP synthase releases energy - which is coupled with ATP synthesis catalysed by ATP synthase
