Physical Sciences 18

Question 1

which steps of ornithine occur in the mitochondria

Answer 1

Where process begins

Ammonia + CO2 –> carbamoyl phosphate
Carbamoyl phosphate + ornithine –> citrulline

carbamoyl phosphate and citrulline

Question 2

what do cells do with ammonia?

Answer 2

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

Question 3

Peptide bonds cost (a lot/a little) energy and we get (a lot/ a little) energy back from breaking them

Answer 3

Peptide bonds are very energy expensive to make and not a lot of energy is gotten back from it

Question 4

how many P bonds for one peptide linkage?

Answer 4

4 high energy peptide bonds for 1 linkage

Question 5

how many calories are stored in a peptide bond?

Answer 5

500-5000

Question 6

what is the rate limiting factor in energy metabolism?

Answer 6

ADP

Question 7

Factors that influence metabolic rate

Answer 7

arousal v. sleep 
skeletal muscle 
age 
thyroid activity 
testosterone 
growth hormone 
fever 
sleep 
malnutrition

Question 8

what is one of the best known stimuli for increasing rate of thyroid stimulating hormone?

Answer 8

cold

this is due to thyroxin

Question 9

what is result of ornithine cycle in cytoplasm?

Answer 9

we end up with fumarate and arginine

arginine is what is converted to urea and ornithine

Question 10

what happens to fumarate?

Answer 10

enters citric acid cycle

Question 11

defects in thyroid and impact on metabolic rate

Answer 11

hypothyroidism = weight gain, lethargy

hyperthyroidism = high energy, increase in metabolic weight

these are due to thyroxine