Energy 2 Flashcards
What does aerobic respiration require?
Presence of oxygen
Requires citric acid cycle + oxidative phosphorylation
Where are enzymes of TCA cycle present in?
Matrix of mitochondria
What occurs in citric acid cycle?
Acetyl CoA reacts with oxaloacetic acid (4C) to form citrate (6C)
Citrate undergoes series of reactions resulting in loss of 2 CO2
3 molecules of NADH + 1 FADH2, one GTP molecule is formed per cycle
What can citric acid cycle use instead of glucose as starting point of cycle ?
Fats, amino acids , proteins
Regulation of enzyme pyruvate dehydrogenase is tissue dependent
What occurs in liver, muscle and adipose tissue?
In muscle, enzyme pyruvate dehydrogenase is activated via action of phosphatase which is stimulated by Ca2+
In liver, Adrenalin increases calcium through activation of adrenergic receptors + IP3
In liver + adipose tissue, insulin stimulates phosphatase which funnels glucose to fatty acid synthesis
How is pyruvate dehydrogenase regulated?
Is negatively regulated by products (NADH and ATP), stimulated by NAD and pyruvate
Balance of negative and positive
How is isocitrate dehydrogenase and a-ketoglutarate dehydrogenase regulated?
Negatively regulated by NADH and ATP, acetyl coA
What is Beriberi?
Is deficiency in thiamine (vit B1)
What is thiamine?
Is prosthetic group for pyruvate and a-ketoglutarate dehydrogenase
What happens to NADH and FADH2 produced?
NADH is accepted by NADH dehydrogenase
FADH2 is accepted by succinate dehydrogenase
What occurs in electron transport chain?
Involves removal of H atoms from NADH + FADH2
H atoms enter ETC + each split to give electron + proton
Electron passes through series of enzymes called cytochromes + finally reacts with molecular O2
H atom is pumped across inner mitochondrial membrane which forms a pH gradient transmembrane potential
This is coupled with ATP synthesis
What does brown fat contain?
Where is it found?
Packed with mitochondria, cytochrome which contains iron
Situated in shoulder region + back
Used to generate heat when it can’t be generated by muscle contraction (shivering)
What is OXPHOS disease?
Common degenerative diseases
Caused by mutation in genes encoding proteins of ETC
Lead to number of symptoms may be evident near birth to early adulthood
What regulates ETC?
Governed by need for ATP
electron transport tightly coupled to phosphorylation I.e. ADP to ATP
Regulated uncoupling leads to generation of heat
