The Nutritional Value of Fats and Proteins Flashcards
How much of a 70kg male is fat?
12kg
How much energy do you get from burning 1g of fat?
37kJ
How long can humans starve for?
40 days
Why are fats important?
as a fuel reserve
Which organ in the body can’t use fat for metabolism?
the brain, RBCs and the testis
What is the neutral lipid for storage?
triacylglycerol
Why does lymph become milky in appearance after a fatty meal?
because fat is absorbed directly into the lymphatics - bypassing the liver
Which hormones mobilise fats and which second messenger do they act by?
adrenaline and glucagon - cAMP
What enzyme breaks down triacylglycerol into free fatty acids?
triacylglycerol lipase
How do free fatty acids travel in the blood?
on serum albumin
What else is exported when free fatty acids are mobilised?
glycerol - which is converted to glucose
What is carnitine?
a molecule which transports fatty acyl-CoA into mitochondria for oxidation
What does carnitine deficiency lead to?
muscle weakness
What inhibits carnitine acyl transferase?
malonyl coA
Where are fats made?
in the cytosol
Where are fats broken down?
in the mitochondria
How many ATP are made per palmitate?
106
Which molecules are ketone bodies?
acetoacetate, beta-hydroxybutyrate, acetone
Where are ketone bodies made?
liver mitochondria
How does ketoacidosis cause a coma?
the drop in pH effects nerve function
What fuels are used in starvation?
glycogen for the first 3 days, then amino acids from muscle, then free fatty acids and glycerol - brain needs to use ketone bodies
Why is fish oil beneficial?
because it promotes prostacyclin production and inhibits thromboxane production
How much of a 70kg male is made up of protein?
12kg
How much protein is required in the diet per day?
0.8g/kg
What is pellagra and what are the symptoms?
a niacin and tryptophan deficiency - symptoms are photosensitive dermatitis, diarrhoea, dementia, death
A diet of solely corn will lead to a deficiency in what amino acid?
tryptophan
What happens to carbons from protein turnover?
they are used as metabolic fuel - either glucogenic, ketogenic or both
What is the final product of nitrogen excretion in humans?
urea
What is the role of alanine?
to carry nitrogen to the kidney or liver
How much protein do we make and break per day?
300g
Are proteins stored?
no
