Cellular Metabolism Flashcards
(20 cards)
What is the prime aim of metabolism?
Use energy and building block from the environment to synthesis macromolecules for cell function
What are the two central themes of metabolism?
- ATP is the universal energy currency
- Biosynthesis uses small building blocks like pyruvate, acteyl-CoA and CAC intermediates
Why are biosynthetic and degradative pathways usually distinct?
To allow independent regulation and efficient metabolic control
What are the three fates of glucose 6 phosphate?
- Glycogen
- Pyruvate
- Ribose 5 phosphate
What are the four metabolic fates of pyruvate?
- Lactate
- Alanine
- Oxaloacetate
- Acetyl-CoA
What are the fates of acetyl-CoA?
- CO2
- Cholesterol
- Ketone bodies
- Fatty acids
Why is oxaloacetate concentration important in metabolism?
- Supports gluconeogenesis, CAC activity and amino acid metabolism
- Regulates oxidative phosphorylation and ketogenesis
Name five levels of metabolic regulation?
- Allosteric interactions
- Covalent modification
- Enzyme levels
- Compartmentation
- Organ specialisation
What is an example of allosteric regulation?
Actetyl-CoA carboxylase in fatty acid synthesis
What is an example of covalent enzyme modification?
Phosphorylation of glycogen phosphorylase during glycogen breakdown
How does the compartmentation regulate metabolism?
Different pathways are restricted to cytosol or mitochondria
How does organ specialisation contribute to regulation?
Organs perform unique function allowing systemic metabolic coordination
What is the liver’s role in metabolism?
- Regulate fuel storage, conversion and release
- Acts as a metabolic buffer
What are the metabolic fuels of the brain?
Glucose and ketone bodies
What are the main metabolic features of muscle?
- Uses glucose, fatty acids and ketones
- Produces lactate and alanine
What are the functions of adipose tissue in metabolism?
- Stores triacylglycerols
- Synthesises and releases fatty acids and glycerol
How does insulin affect metabolism?
Increase glycogen synthesis and glycolysis and decreases gluconeogenesis
What is the role of glucagon in metabolism?
Increases gluconeogenesis and glycogen breakdown and decreases glycolysis
What is the role of adrenaline in metabolism?
Targets muscle to increase glycogen breakdown, gluconeogenesis and fatty acid oxidation
What changes occur in metabolism during prolonged starvation?
- Decreased insulin and glycolysis
- Increased glucagon, adrenaline, gluconeogenesis, lipolysis, fatty oxidation and ketogenesis
