case 6 - extra Flashcards
where does the Kreb’s/citric cylce occur
occurs in the matrix of the mitochondrion
what happens in this step and what does this release
in this step, the acetyl CoA is degraded into carbon dioxide and hydrogen atoms
the release of hydrogen atoms will be used later
describe the steps 1-6 of what happens next
Acetate is offloaded from CoA and joins with Oxaloacetate to form citrate.
Citrate is decarboxlyated and dehydrogenated to form a 5C compound.
The hydrogen atoms are accepted by NAD, which take them to the Electron Transport Chain
The Carboxyl group becomes CO2.
The 5C compound is decarboxylated and dehydrogenated to form a 4C compound.
The 4C compound is changed into another 4C compound, and a molecule of ATP is phosphorylated.
The second 4C compound is changed into a third 4C compound and a pair of hydrogen atoms are removed, reducing FAD.
The third 4C compound is further dehydrogenated to regenerate oxaloacetate.
what is entered into the cycle for the net reaction per molecule of glucose
2 acetyl-CoA molecules
6 molecules of water
what is released from the cycle
4 carbon dioxide molecules
16 hydrogen atoms
2 molecules of coenzyme
2 molecules of ATP are formed (one acetyl CoA molecule = one ATP molecule)
6 NADH
for every molecule of glucose, the first three stages of carbohydrate metabolisms makes:
4 molecules of ATP
24 molecules of hydrogen atoms
what enters oxidative phosphorylation
20/24 hydrogen atoms that were formed before combine with nicotinamide adenine dinucleotide (NAD+) under the influence of a dehydrogenase enzyme.
This forms NADH and H+, which enter oxidative phosphorylation.
what is the final stage of respiration
oxidative phosphorylation
what does oxidative phosphorylation involve
electron carriers embedded in the mitochondrial membrane
describe oxidative phosphorylation
These membranes are folded into cristae, which increases the surface area for electron carriers and ATP synthase enzymes.
Oxidative phosphorylation is the formation of ATP by the addition of an inorganic phosphate to ADP in the presence of oxygen.
As protons flow through ATPsynthase, they drive the rotation part of the enzyme and join ADP to Pi to make ATP.
The electrons are passed from the final electron carrier to molecular oxygen, which is the final electron acceptor.
Hydrogen ions also join, so oxygen is reduced to water
does anaerobic or aerobic respiration produce a higher yeild
anaerobic respiration produces a much lower yield of ATP than aerobic respiration because only glycolysis takes place in anaerobic respiration
what are the 5 steps in carbohydrate metabolism overall
- glycolysis
- link reaction
- citric acid cycle
- oxidative phosphorylation
- The remaining four hydrogen atoms are released by their dehydrogenase. Two ATP molecules are usually released for every two hydrogen atoms oxidized, thus giving a total of 4 more ATP molecules.
what are ketone bodies
are an emergency fuel that the liver can produce to preserve glucose.
can the liver use these ketone bodies itself
no
what happens during starvation
the ability of the liver to oxidise fatty acids released from adipocytes may be limited
features of ketone bodies
are highly soluble and unlike lipids can be transported without carriers
what is observed in uncontrolled type I diabetes
increased levels of ketone bodies in blood and urine - ketonemia and ketonuria
what does the acidity of ketone bodies do
lowers blood pH - ketoacidosis
what do delta cells in the pancreas secrete
somatostatin
what do the PP cells of the pancreas do
secrete pancreatic polypeptide
what inhibits glucagon secretion
insulin
what inhibits insulin secretion
amylin
what inhibits the secretion of both insulin and glucagon
somatostatin
what are the two things the insulin does in the blood
Binds to insulin receptors in target cells.
The remainder is degraded by the enzyme insulinase mainly in the liver, to a lesser extent in the kidneys and muscles, and slightly in most other tissues.