aerobic respiration Flashcards
what does the link reaction convert pyruvate into and what are the steps
1) pyruvate is decarboxylated, a carbon is removed in the form of co2
2) pyruvate is oxidised to form acetate and NAD is reduced to form reduced NAD
3) acetate is combined with coenzyme A to form acetyl coenzyme A
4) no ATP is produced in this reaction
why does the link reaction occur twice for each glucose molecule
because the link reaction occurs once for each pyruvate molecule, but glucose turns into 2 pyruvate molecules so it has to happen twice for each glucose molecule
describe the krebs cycle in stages
1) acetly CoA combines with oxaloacetate to form citrate
2) decarboxylation occurs to convert the 6C citrate molecule into a 5C molecule in the form of a co2 molecule
3) dehydrogenation also occurs where a hydrogen is removed, the hydrogen is used to produce reduced NAD from NAD
4) the 5C molecule is converted into a 4C molecule, decarboxylation and dehydrogenation occurs which produces one molecule of reduced FAD and two of reduced NAD
5) ATP is produced by the direct transfer of a phosphate group from an intermediate compound to ADP, citrate has now been converted into oxaloacetate
where does CoA go after being used in the krebs cycle
back into the link reaction to be reused
what is substrate level phosphorylation
when a phosphate group is directly transferred from one molecule to another
explain how oxidative phosphorylation works (long)
1) hydrogen atoms from NADH and FADH are released so they’re oxidised to NAD and FAD, the hydrogen atoms are split into H+ and E-
2) the electrons move down the electron transport chain losing energy at each stage
3) the energy from these electrons is used to pump protons from the mitochondrial matrix into the intermembrane space
4) there’s now a higher concentration of hydrogen ions in the intermembrane space which creates an electrochemical gradient
5) protons then move back into the mitochondrial matrix down the electrochemical gradient via ATP synthase, this movement drives the synthesis of ADP and Pi to form ATP
6) in the mitochondrial matrix the electrons, hydrogens and o2 molecules ( from the blood) combine to form water, oxygen is the final electron acceptor
what is an electron transport chain made of
electron carriers
what is an electrochemical gradient
a gradient formed by a higher concentration of electrons compared to somewhere with a lower concentration
what is chemiosmosis
the synthesis of ATP production from the movement of hydrogens
how much ATP is made from one reduced NAD
2.5
how much ATP is made from one reduced FAD
1.5
how can mitochondrial diseases affect ATP production
they can affect the proteins involved in oxidative phosphorylation or the krebs cycle which reduces ATP production
what problems can an increase in anaerbic respiration lead to
anaerbic respiartion may increase to make up for the shortage of ATP which results in a lot of lactate being produced which causes muscle fatigue and weakness, some lacate may also diffuse into the bloodstream which leads to high lactate blood concentrations
what other substances can be used as the substrate in aerobic respiration
fatty acids from lipids and amino acids from proteins, these can be converted into products that can enter the krebs cycle
