proteins and fat metabolism

Question 0

why are lipids a more premium reserve of energy compared to glycogen

Answer 0

because it is hydrophobic and therefore does not require water to be stored alongside it

Question 1

how much of our protein do we break down and remake each day

Answer 1

300g

Question 2

can FAs be converted into glucose? Why or Why not?

Answer 2

No

because there is no conversion possible going from acetyl CoA back to pyruvate

Question 3

what is the amount of fat, protein and glycogen fuel reserve in MJ

Answer 3

400MJ - fat
100MJ - protein
6.5MJ - glycogen

Question 4

what does the brain use as a substrate for energy during starvation

Answer 4

ketone bodies (derived from FA - but cannot use FA directly)

Question 5

why are FAs stored as TAG

Answer 5

because free fatty acids are detergents and dangerously acidic

Question 6

where do the lacteals of the gut drain to

Answer 6

the thoracic duct

Question 7

how does beta oxidation of FA occur

Answer 7

within the mitochondria (enters mitochondria via carnitine mechanism)

Question 8

how are free FA transported in the blood

Answer 8

bound to serum albumin

Question 9

what is the association between FFA and MII

Answer 9

if the amount of FA released exceeds the carrying capacity of serum albumin –> MI following sustained physical stress

Question 10

which tissues cannot use FA as a fuel

Answer 10

brain
RBCs
testis

Question 11

explain the regulation of the mitochondria oxidising FA

Answer 11

acetyl CoA is only shuttled into the mitochondria by carnitine when you are in a fasting state (as requires malonyl-CoA - an enzyme that occurs only in the fed state inhibits transferase 1)

Question 12

how is acetyl CoA used for energy during starvation state

Answer 12

enters the Krebs cycle to make 106ATP per palmitate

Question 13

what are the ketone bodies

Answer 13

acetoacetate
beta-hydroxybutyrate
acetone

Question 14

what is the order of preference when using substrates for energy

Answer 14

glucose
protein
fat

Question 15

why are EPA and DHA essential FA

Answer 15

because they are essential for the retina

Question 16

positive functions of omega 3

Answer 16

• inhibits thromboxane (antithrombolitic)
• promotes prostacyclin (antithrombolitic)
• inhibits leukotriene synthesis (reduced inflammation)

Question 17

explain the “nitrogen balance” of children

Answer 17

children - have positive nitrogen balance during growth (more in than out)

Question 18

which situations will lead to a negative nitrogen balance

Answer 18

starvation
burns
cancer
AIDS 
surgery

Question 19

what causes pellagra

Answer 19

niacin deficiency due to a diet primarily consisting of corn which is tryptophan deficiency (niacin precursor)

Question 20

clinical signs of pellegra

Answer 20

4 Ds:

• photosensitive Dermatitis - Casal’s collar
• Diarrhoea
• Dementia
• Death

Question 21

why are legumes the richest source of nitrogen in plants

Answer 21

because they fix nitrogen in nodules

Question 22

corn is deficient in which amino acid

Answer 22

tryptophan

Question 23

which amino acid can be destroyed with the Maillard reaction

Answer 23

lysine

Question 24

what is transamination

Answer 24

the link between amino acids and keto acids

Question 25

what is the alanine cycle used for

Answer 25

to carry excess nitrogen to the liver or kidneys

Question 26

cause of gout

Answer 26

high levels of uric acid leading to crystals forming and inflammation in the joints predominantly