Energy II Flashcards
Where does the citric acid cycle take place?
Takes place in the mitochondrial matrix
What is pyruvate converted into?
Pyruvate converted to acetyl CoA
What is produced from the citric acid cycle?
CO2 and NADH produced
How is citrate formed in citric acid cycle?
Acetyl CoA reacts with Oxaloacetate to form citrate
What is released when citrate undergoes further reactions for each glucose molecule?
○ 4 CO2
○ 6 NADH
○ 2 FADH2
2 GTP
What type of reaction is the formation of acetyl CoA?
Irreversible
What therefore happens to glucose if formation of acetyl CoA is irreversible?
Therefore glucose either oxidised to CO2 and energy production or fatty acid synthesis
What is the enzyme involved in the formation of acetyl CoA?
Pyruvate hydrogenase
What is pyruvate hydrogenase inhibited by?
Inhibited by NADH and acetyl CoA
Also regulated by phosphorylation by a kinase and phosphate because phosphorylation inhibits this enzyme
How is pyruvate dehydrogenase activated?
In muscle, pyruvate dehydrogenase is activated again via the action of a phosphate- this enzyme is stimulated by Ca2+
In the liver, what does adrenaline do?
In liver, adrenaline increases calcium through the activation of a adrenergic receptor and IP3
What does insulin stimulate in the liver and adipose tissue?
In liver and adipose tissue, Insulin stimulates the phosphate which funnels glucose to fatty acid synthesis
Enzyme involved in the formation of citrate and its reaction
Acetyl CoA reacts with oxaloacetate forming citrate using citrate synthase
Formation of alpha ketoglutarate
Isocitrate into α-ketoglutarate using Isocitrate dehydorgenase
What enzyme converts alpha ketoglutarate to succinyl CoA
α-ketoglutarate is converted to Succinyl CoA by the enzyme α-keto gluterate dehydrogenase
List the negative regulators of the citric acid cycle
Negative regulators NADH, ATP and Acetyl CoA
What are negative regulators stimulated by?
Stimulated by ADP and pyruvate
What deficiency cause Beriberi?
Deficiency in thiamine
Where is Beriberi common?
Common where rice is a staple food
What is Beriberi characterised by?
Characterised by cardiac and neurological symptoms.
What is Thiamine a prosthetic group for?
Thiamine is a prosthetic group for pyruvate and α-ketogluterate dehydrogenase
Why are neurological disorders in Beriberi common?
Neurological disorder are common as glucose is the primary source of energy
What is the electron transport chain responsible for?
Responsible for producing ATP by oxidative phosphorylation
What does NADH donate?
NADH will donate H atom which splits into proton and electron
Where are the protons pumped?
Proton pumped into intermembrane space and electrons passed from complex to complex
What happens to the electrons as they’re passed along the membrane?
Looses energy as its passed along which is required to pump out the protons
In what condition are the protons pumped?
Protons pumped against their concentration gradient
What happens to oxygen?
Oxygen is reduced and water is formed
What does the concentration gradient generate?
Gradient generates ATP
How many ATPs does every NADH form?
Every NADH forms 3 ATPs
How many ATPs FADH 2 form?
2 ATPs
How many H+ does NADH pump out?
Pumps out 10 H+
How many H+ does FADH2 pump out?
Pump out 6 H+
How is ATP generated across the membrane?
H+ ions pumped across membrane through ATP synthase to generate ATP
What physiological reason is in new born infants?
• Physiological reason where gradient is uncoupled from production of ATP is in new born infants
○ In brown fat, protons are instead let through back into the matrix using a protein channel called thermogenin which generates heat instead of ATP.
What type of disease is OXPHOS?
Degenerative disease
What is OXPHOS disease caused by?
Caused by a mutation in genes encoding proteins of ETC
What symptoms does OXPHOS disease lead to?
Lead to a number of symptoms including fatigue, epilepsy and dementia
What are the metabolic consequences of OXPHOS disease?
Metabolic consequence can be congenital lactic acidosis
When is the ETC stimulated?
When a cell requires ATP, the ETC is stimulated
What is the ETC tightly coupled to?
Tightly coupled to phosphorylation
What does regulation uncoupling lead to ?
Leads to the generation of heat
