IMMS: Week 5 Flashcards
Give three examples of fatty acids
Oleic
Palmitic
Stearic
Where is the electron transport chain locacted
Inner mitochondrial membrane
What is contained in the inner mitochondrial membrane surface
Cytochromes
What does a cytochrome contain
Iron and copper co-factors
Describe what happens in the Electron transport chain
Check book
How many molecules of ATP are produced for each molecule of NADH
2.5
How many molecules of ATP are produced for each molecule of FADH2
1.5
What is the overall reaction of aerobic respiration
C6H12O6 + 6O2 + 38ADP + 38 Pi -> 6CO2 + 6H20 + 34-38 ATP
What do we have to assume about oxidative phosphorylation, glycolysis and kerb’s cycle to state 38ATP molecules are produced from them
That all NADH produced in glycolysis and Kreb’s cycle enter oxidative phosphorylation and ALL H+ are used in chemiosmosis
Why does ketogenesis take place
Because some acetyl coA exceed the capacity of the Kreb’s cycle and so need to be used to make ketone bodies instead
Were are ketone bodies produced
Mitochondrial matrix
Describe the process of ketogenesis
Look in book
What happens to acetoacetate after ketogenesis
It is converted to acetone and expired by the lungs
What happens to the level of oxaloacetate when carbohydrate utilisation is low or deficient
Oxaloacetate levels will also be low
What happens to acetoacetate and b-hydroxybutyrate after ketogenesis
It is used as fuel in many tissues
What happens to acetoacetate and b-hydroxybutyrate in skeletal muscles
- Taken into cytosol and into mitochondrial matrix
- B-hydrobutyrate -> acetoacetate
- Acetoacetate -> Acetoacetyl CoA
- Acetoacetyl CoA -> Two molecules of Acetyl CoA
- Acetyl CoA used in Kreb’s Cycle
What converts acetoacetyl CoA to Acetyl CoA
Thiolase enzyme
Why can’t the liver use ketones as a fuel
No presence of SUCCINYL COA which is needed to convert acetoacetate to acetoacetyl CoA
Can’t be used to produce Acetyl CoA
How is ketogenesis controlled
By the rate of release of fatty acids from adipose tissue
In what organ does ketogenesis take place
Liver
What causes the rate of production of ketone bodies to increase
Decrease in carbohydrate stores
How does diabetic ketoacidosis occur
From reduced supply of glucose and increased in fatty acid oxidation
Increased Acetyl CoA -> Increased Ketogenesis
Kettles are strong acids so this lowers blood pH
What is the pH of ketone bodies
3.5
What is the problem of diabetic ketoacidosis
Impairs ability for haemoglobin to bind to oxygen
What are ROS
Reactive Oxygen Species:
Highly reactive oxygen containing compounds that are free radicals (unpaired electrons in their orbital)
Why are radicals so reactive
Because they try to extract electrons from other compounds to fill their outer orbitals
What is the most potent ROS
Hydroxyl
Where are exogenous sources of ROS
UV, tobacco and drugs
What are endogenous sources of ROS
NADPH and ECT
How do Oxygen radicals form
Check book
Why is H2O2 considered an ROS
Because it is readily converted to the OH radical in cells
Lipid soluble so can cause damage away from site of formation
What compounds catalyse the formation of a hydroxyl radical from hydrogen peroxide
Fe2+ and Cu2+
What is the reaction of formation of hydroxyl radicals from hydrogen peroxide
Fenton reaction
Describe the Fenton Reaction
H2O2 + Fe2+ -> Fe3+ + OH- + OH (radical)
What two reactions are found in the Haber-Weiss Reaction
Fenton Reaction
Haber-Weiss Reaction
What two reactions do hydroxyl radicals initiate
Lipid Peroxides
Organic Radicals
What compound do free radicals DAMAGE
Proteins, lipids, carbohydrates and nucleic acids
What membranes do free radicals they damage
Cells
Nuclear
Mitochondrial
ER
Is DNA affected by the hydroxyl radical
Yes, it damages DNA and causes mutations
What are respiratory bursts
Immune system defence against bacteria
When are ROS released by immune cells
Following phagocytosis
How do ROS form through immune cells
- NADPH oxidase reduces oxygen to superoxide
2. Superoxide is reduced to H2O2 -> OH radical
What happens to ROS produced by immune cells
Myeloperoxidases combine H2O2 with CL- to produce CLO-
What is CLO- needed for
Destroying bacteria by damaging bacterial cell membranes
What enzyme converts superoxide to hydrogen peroxide and oxygen
Superoxide dismutase
What enzyme catalyses conversion of hydrogen peroxide to water and oxygen
Catalase
What is the role of catalase in the immune system
Protects WBCs against own rest bursts
What enzyme catalyses the reduction of H2O2 to water and a disulphide
Glutathione Peroxidase
What are two antioxidant vitamins
E and C
Role of E
Protects against lipid per oxidation and stops free radical propagation in membranes
Role of C
Reacts with superoxide and hydroxyl radical
What is the Henderson Hasselbalch Equation
pH = pKa + log([HCO3-]/[CO2])
What is the role of protein matrix of the bone
Buffer large amounts of H+ in patients with chronic acidosis
What pH results in academia
Less than 7.35
What pH results in alkalaemia
More than 7.45
What PaCO2 level is a sign of respiratory acidosis
> 6 kPa
What PaCO2 level is a sign of respiratory alkalosis
<4.5 kPa
