Acetyl CoA, Mitochondria & O2 Flashcards
When does aerobic respiration occur?
Only in the presence of O2
Where does Aerobic respiration occur?
In the mitochondria
Which processes are required to occur for aerobic respiration to occur?
Citric Acid Cycle
Oxidative Phosphorylation
What is the significance of aerobic respiration?
Yields more energy in ATP form
List the functions of mitochondria in a cell
- Hydrolyse fatty acids into Acetyl CoA (gain energy)
- Decarboxylate Pyruvate into Acetyl CoA
- Citric Acid Cycle
- Oxidative Phosphorylation
- Thermogenesis
What is the significance of the Citric Acid Cycle?
Pivotal metabolic pathway generating reducing equivelants for ATP generation and metabolic intermediates for anabolic pathways
What is Thermogenesis?
When the energy stored in ATP is released to generate heat
Summarise Oxidative Phosphorylation
Formation of ATP from ADP + Pi
- reducing equivelants derived from the breakdown of
Acetyl CoA
- electrons combine with O2 to form H2O
Who is thermogenesis especially useful for?
Infants and mammals living in low temp
What gives brown fat cells their brown colour?
They contain lots of mitochondria to generate heat giving them brown appearance
What are the products of the Citric Acid Cycle?
3NADH, 2FADH, 1 GTP
Outline the stages of the citric acid cycle
In presence of O2
- Pyruvate converted to Acetyl CoA (2C)
- Acetyl CoA reacts with oxaloacetate acid (4C)
=> forms citrate (6C)
- Citrate loses 2CO2 molecules via a series of reactions
- 3 NADH and 2FADH molecules are released
- 1 GTP molecule is formed
Where do the electrons required for oxidative phosphorylation come from?
The Citric Acid Cycle
How is the Citric Acid Cycle regulated?
The formation of Acetyl CoA from pyruvate is irreversible
Why is the Citric Acid Cycle so significant to the whole body?
Integrates Carbohydrate, lipid and protein metabolism
- source of building blocks for most important bio
molecules
How does formation of Acetyl CoA from Pyruvate being irreversible regulate the cycle?
This commits the glucose carbon skeleton to either oxidation or fatty acid synthesis
What enzyme is involved in the conversion of pyruvate into Acetyl CoA?
Pyruvate Dehydrogenase
How is the conversion of pyruvate to Acetyl CoA inhibited?
Inhibited by NADH and Acetyl CoA
Regulated by phosphatase and kinase
How does the reaction occur in muscle?
Pyruvate dehydrogenase activated by a phosphatase stimulated by calcium ions
How is the phosphatase enzyme stimulated in the liver?
Insulin stimulates phosphatase which funnels glucose to fatty acid synthesis
How is fatty acid synthesis triggered?
Adrenaline increases calcium influx through the activation of adrenergic receptors and IP3
How does NADH and Acetyl CoA regulate glucose production?
Build up of NADH and Acetyl CoA inform sthe enzyme, the cells energy requirements are being met/ fatty acids are being hydrolysed
- spares glucose
What is the BeriBeri disease?
Thiamine deficiency in thiamine (vitamin B1)
- thiamine is a prosthetic group for pyruvate and ɒ
ketogluterate dehydrogenase
List some symptoms of Beriberi disease
Cardiac issues
neurological issues - common as glucose primary source of energy
