The Liver and Gluconeogenesis Flashcards
What is glucose a source for?
Glucose is a source of energy
A source of NADPH
Source of pentode sugars for synthetic reaction
Source of carbon for other sugars
What are the advantages of glucose?
Water soluble
Does not require a carrier in circulation
Can cross blood brain barrier
Can be oxidised anaerobically
What are the disadvantages of glucose?
Low yield of ATP compared to FA
Osmotically active
High concentrations can damage cells
What is the function of glycolysis?
Anaerobic muscle contraction
What is the function of TCA cycle?
Energy
What is the glucose 6 phosphate pathway?
Glucose 6 phosphate -> 6 phosphogluconate -> Ribulose 5 phosphate -> ribose 5 phosphate -> nucleotides, coenzymes, DNA and RNA
Where is blood glucose sourced from?
Diet, liver glycogen and gluconeogenesis
What happens in gluconeogenesis?
In conditions of carbohydrate deprivation, glucose is synthesised from non-carbohydrate sources in the liver, from lactate, glycerol and gluconeogenic amino acids
Gluconeogenesis is effectively the reverse of glycolysis and uses pyruvate to form glucose
What coordinates gluconeogenesis?
Insulin, glucagon and adrenaline as well as glucose signal the activities
What are islets of langerhans?
They are seen with alpha and beta cells
Alpha cells secrete glucagon
Beta cells secrete insulin
What is insulin?
It’s an anabolic hormone which promotes synthesis and storage of carbohydrates
What is glucagon?
It is an catabolic hormone that promotes the degradation of stored fuel
What can inhibit insulin?
Adrenaline
What are the metabolic effects of insulin in the liver?
Inhibits gluconeogensis
Activates glycogen synthesis
Increases fatty acid synthesis
Increased amino acid uptake and protein synthesis
What are the metabolic effects of insulin in the muscle?
Increased glucose uptake
Increased amino acid uptake and protein synthesis
Activation of glycogen synthesis
Glucagon acts in the liver
