Amino Acid Metabolism and Urea Cycle Flashcards
What is the function of the liver?
Detoxification; breaking down of substances so that they can be excreted
Homeostasis; Maintain sufficient plasma levels of the metabolites in the body
How is ethanol converted to acetyl-CoA?
- Ethanol is oxidised to acetaldehyde with the help of alcohol dehydrogenase
- Acetaldehyde is oxidised to acetate with the help of aldehyde dehydrogenase
- Acetate is then converted to acetyl-CoA
What happens when there is a build-up of NADH?
Further metabolism of acetyl-CoA via the citric acid cycle would be inhibited
Most of the acetyl-CoA (formed from ethanol) will be used to synthesize fatty acids which would then be assembled into triglycerides
What happens when acetaldehyde accumulates?
Acetaldehyde is toxic
Accumulated acetaldehyde will inhibit mitochondria reactions and functions
When acetaldehyde reaches a saturation point, some of it will escape into the bloodstream
How effective is the body in dealing with large amounts of ethanol?
Not very effective
Toxic effects still remain
Toxic effects will increase with the production of acetaldehyde
Ethanol metabolism disrupts normal metabolism, causing the accumulation of fatty acids in the liver
What happens during transamination?
Amine group on 1 amino acid is exchanged with the keto group on the keto acid
The process is done by aminotransferase
What happens during oxidative deamination?
Amine group is removed from an amino acid for urea synthesis
Keto acid is produced
This process is done by glutamate dehydrogenase
How is ammonia, from deamination in tissues, transported to the liver?
Glutamine synthetase transfers the ammonia to glutamate, forming glutamine
Glutamine leaves the cell and travel to the liver via blood
In the liver, glutamine is converted to glutamate which is then converted to alpha-ketoglutarate and ammonia
How is ammonia, from deamination in the muscles, transported to the liver?
Ammonia combines with alpha-ketoglutarate (in muscles) to form glutamate
Glutamate is re-converted back to alpha-ketoglutarate, producing alanine at the same time
Alanine is transported to the liver
In the liver. alanine is converted to pyruvate which is then used to make glucose
Function of kidney
excretion of wastes and toxins
filter out water-soluble waste products and environmental toxins into urine for excretion
What is urine dipstick chemical analysis?
Dipstick undergoes a colour change when certain constituents of the urine are present/ in a certain concentration
Dipstick is dipped into the urine sample colour change is compared to a standard chart to determine findings
What is macroscopic urinalysis?
Direct visual observation
