The Nutritional Value of Fats and Proteins

Question 1

How much of a 70kg male is fat?

Answer 1

12kg

Question 2

How much energy do you get from burning 1g of fat?

Answer 2

37kJ

Question 3

How long can humans starve for?

Answer 3

40 days

Question 4

Why are fats important?

Answer 4

as a fuel reserve

Question 5

Which organ in the body can’t use fat for metabolism?

Answer 5

the brain, RBCs and the testis

Question 6

What is the neutral lipid for storage?

Answer 6

triacylglycerol

Question 7

Why does lymph become milky in appearance after a fatty meal?

Answer 7

because fat is absorbed directly into the lymphatics - bypassing the liver

Question 8

Which hormones mobilise fats and which second messenger do they act by?

Answer 8

adrenaline and glucagon - cAMP

Question 9

What enzyme breaks down triacylglycerol into free fatty acids?

Answer 9

triacylglycerol lipase

Question 10

How do free fatty acids travel in the blood?

Answer 10

on serum albumin

Question 11

What else is exported when free fatty acids are mobilised?

Answer 11

glycerol - which is converted to glucose

Question 12

What is carnitine?

Answer 12

a molecule which transports fatty acyl-CoA into mitochondria for oxidation

Question 13

What does carnitine deficiency lead to?

Answer 13

muscle weakness

Question 14

What inhibits carnitine acyl transferase?

Answer 14

malonyl coA

Question 15

Where are fats made?

Answer 15

in the cytosol

Question 16

Where are fats broken down?

Answer 16

in the mitochondria

Question 17

How many ATP are made per palmitate?

Answer 17

106

Question 18

Which molecules are ketone bodies?

Answer 18

acetoacetate, beta-hydroxybutyrate, acetone

Question 19

Where are ketone bodies made?

Answer 19

liver mitochondria

Question 20

How does ketoacidosis cause a coma?

Answer 20

the drop in pH effects nerve function

Question 21

What fuels are used in starvation?

Answer 21

glycogen for the first 3 days, then amino acids from muscle, then free fatty acids and glycerol - brain needs to use ketone bodies

Question 22

Why is fish oil beneficial?

Answer 22

because it promotes prostacyclin production and inhibits thromboxane production

Question 23

How much of a 70kg male is made up of protein?

Answer 23

12kg

Question 24

How much protein is required in the diet per day?

Answer 24

0.8g/kg

Question 25

What is pellagra and what are the symptoms?

Answer 25

a niacin and tryptophan deficiency - symptoms are photosensitive dermatitis, diarrhoea, dementia, death

Question 26

A diet of solely corn will lead to a deficiency in what amino acid?

Answer 26

tryptophan

Question 27

What happens to carbons from protein turnover?

Answer 27

they are used as metabolic fuel - either glucogenic, ketogenic or both

Question 28

What is the final product of nitrogen excretion in humans?

Answer 28

urea

Question 29

What is the role of alanine?

Answer 29

to carry nitrogen to the kidney or liver

Question 30

How much protein do we make and break per day?

Answer 30

300g

Question 31

Are proteins stored?

Answer 31

no