Wk 3 Fats

Question 1

Dietary fat classifications (3)

Answer 1

FA/triglycerides (95%)
Phospholipids eg lecithin
Sterols eg cholesterol

Question 2

Types of unsaturated fat w/ examples

Answer 2

• Trans fats - partially hydrogenated oils
• Polyunsaturated fats - soybean oil; EPA/DHA
• Monounsaturated fats - nuts, avocado

Question 3

Dietary fat - importance:

Answer 3

dense source of energy/cals, rich source of vitamins A D E K, provide essential fats - omega 3 and 6, makes food palatable.

Question 4

Body fat - functions:

Answer 4

source of energy, insulate against heat loss, keep skin and other tissues soft and pliable, organ protection, structural; cell membranes, steroid hormones eg test, nerve insulation (myelin) - efficient transmission of nerve impulses. Protects against infection in skin and cushioning for organs by protecting from impact. Role in cell membrane synthesis.

Question 5

What is white fat and brown fat?

Answer 5

white fat is adipose tissue around organs, stores energy, brown fat is used for insulation - esp in babies?

Question 6

Fat can be stored in muscle as _

Answer 6

Triglyceride

Question 7

Fat storage sites:

Answer 7

adipose tissue triglycerides (TAG), intramuscular triglyceride (IMTG), plasma triglyceride

Question 8

What might limit the use of fat as a fuel?

Answer 8

Lipolysis
Removal of FAs from the fat cell and transport
Transport of FAs into the muscle cell
Transport of FAs into the mitochondria

Question 9

Lipolysis =

Answer 9

breakdown of triglyceride to 3 fatty acids and glycerol

Question 10

Lipolysis is regulated by _ which are stimulated by incr hormones eg _, _, _ and decr by _.

Answer 10

Lipolysis is regulated by lipases which are stimulated by incr hormones eg epinephrine, glucagon, cortisol and decr by insulin.

Question 11

removal of FAs from the adipocyte into the bloodstream depends on…

Answer 11

the albumin concentration in the blood, number of free binding sites for FAs on albumin, blood flow to the adipose tissue.

Question 12

Transport of FAs into the muscle cell increases linearly with increased _ _, regulated by _ proteins eg _/, _

Answer 12

Transport of FAs into the muscle cell increases linearly with increased blood concentration, regulated by carrier proteins eg fat/CD36, FABP

Question 13

Transport of FAs into the mitochondria involves _ and _ of __ and the carrier _

Answer 13

Transport of FAs into the mitochondria involves degradation and synthesis of fatty acids and the carrier carnitine

Question 14

Beta-oxidation =

Answer 14

Breakdown of fatty acids into acetyl Co-A by removing two carbons from the carbon chain

Question 15

When are ketone bodies released?

Answer 15

When there is too little oxaloacetate to combine with Acetyl CoA, and there is excessive buildup of Acetyl CoA

Question 16

Re-esterification =

Answer 16

rejoining of fatty acids to molecule chain

Question 17

Crossover =

Answer 17

point at which breakdown of FAs cant keep up w exercise demands.

Question 18

Fuel contribution during exercise - at 65% and 85% VO2max:

Answer 18

As incr intensity, like 65 vo2max, glycogen starts to increase and almost dominate as fuel source. Above 85 vo2max, muscle glycogen and blood glucose dominates. Plasma FA contribution decreases at very high fitness levels, but oxidation is more efficient.

Question 19

types of ketones:

Answer 19

acetoacetate, B-hydroxybutyrate, acetone

Question 20

Ketones are produced in the ___ in response to ___ or _____

Answer 20

Produced in the liver in response to starvation/very low CHO intake.

Question 21

Typical ketone level is..

Answer 21

<0.5mmol/L.

Question 22

Ketoacidosis can only be entered by ___

Answer 22

diabetics

Question 23

Inability to slow production of ketone bodies leads to…

Answer 23

Diabetic coma caused by keotacidosis

Question 24

Fat intake recommendations:

Answer 24

• 10% saturated FAs, avoid trans fats.

- Fat intake should not drop below 0.5g/kg body mass or 20% of total energy intake. - Total fat 20-35% of calories.

Question 25

Exercise increases fat ___

Answer 25

oxidation

Question 26

_____ switches off fat oxidation

Answer 26

carb feeding

Question 27

Exercise leads to increased ____ and _____

Answer 27

icnr rate of lipolysis and incr FA release from adipose tissue.

Question 28

After 1 hr of moderate exercise, plasma FAs may reach ___

Answer 28

1 mmol/L.