Physical Sciences 18 Flashcards
which steps of ornithine occur in the mitochondria
Where process begins
Ammonia + CO2 –> carbamoyl phosphate
Carbamoyl phosphate + ornithine –> citrulline
carbamoyl phosphate and citrulline
what do cells do with ammonia?
we get ammonia when we use proteins for energy
ammonia is toxic, so cells convert it to urea
urea can be tolerated to maintain blood osmolarity
Peptide bonds cost (a lot/a little) energy and we get (a lot/ a little) energy back from breaking them
Peptide bonds are very energy expensive to make and not a lot of energy is gotten back from it
how many P bonds for one peptide linkage?
4 high energy peptide bonds for 1 linkage
how many calories are stored in a peptide bond?
500-5000
what is the rate limiting factor in energy metabolism?
ADP
Factors that influence metabolic rate
arousal v. sleep skeletal muscle age thyroid activity testosterone growth hormone fever sleep malnutrition
what is one of the best known stimuli for increasing rate of thyroid stimulating hormone?
cold
this is due to thyroxin
what is result of ornithine cycle in cytoplasm?
we end up with fumarate and arginine
arginine is what is converted to urea and ornithine
what happens to fumarate?
enters citric acid cycle
defects in thyroid and impact on metabolic rate
hypothyroidism = weight gain, lethargy
hyperthyroidism = high energy, increase in metabolic weight
these are due to thyroxine