Fat Metabolism, Interaction of Fat and Carbohydrate Metabolism, Exercise Training Effects Flashcards

1
Q

what is the body’s most plentiful source of energy

A

stored lipid

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2
Q

lipids store ____ as much energy as CHO for an equal amount of ____

A

2x; weight

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3
Q

lipids are an important source of energy in what kind of exercise

A

prolonged mild to moderate intensity

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4
Q

2 sites of stored lipids

A
  • adipose tissue
  • intramuscular
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5
Q

source of lipids for metabolism

A
  1. circulating triglycerides from VLDL or chylomicrons
  2. TG stored w/in muscle
  3. circulating FFA mobilized from TG in adipose tissue
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6
Q

circulating TG from VLDL occurs when

A

after eating (postprandial)

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7
Q

95% of fat in the diet is

A

TG

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8
Q

5% of fat in the diet is

A

sterols (cholesterol) & phospholipids

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9
Q

structure of TG

A

glycerol backbone + 3 FA

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10
Q

lipolysis

A

the breakdown of fat in adipose or muscle tissue to FFA and glycerol

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11
Q

7 step overview of fat metabolism

A
  1. Mobilization
  2. Circulation
  3. Uptake
  4. Activation
  5. Translocation
  6. b-oxidation
  7. Mitochondrial Oxidation
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12
Q
  1. mobilization : important enzyme and what it does
A

hormone sensitive lipase
- stimulates lipolysis and promotes fat release into the blood

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13
Q

HSL is found within

A

adipose tissue

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14
Q

HSL is inhibited by

A

insulin

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15
Q

HSL is stimulated by

A

epinephrine and norepinephrine (catecholamines)

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16
Q

2: circulation: interaction btwn fat and blood and what this means for circulation of fat within the circulatory system

A
  • FFA are insoluble in blood (blood is mostly water)
  • transported by albumin
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17
Q

FFA transported in the blood by

A

albumin

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18
Q
  1. uptake : how do FFA enter the muscle cell
A

FFA enters via a specific receptor site on the sarcolemma, called fatty acid binding protein (FABP)

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19
Q

FABP are

A

a family of molecules that transport FA throughout the cell

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20
Q
  1. activation: what are the compounds that act on FFA in order to activate them
A
  • CoA
  • 2 ATP
  • Acyl-CoA synthase
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21
Q
  1. translocation : activated FA must be transported into
A

mitochondria

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22
Q
  1. translocation: what facilitates the transfer of the activated FA into the mitochondrial matrix
A

carnitine acyltransferase (CAT)

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23
Q

where is CAT located

A

on the inner mitochondrial membrane

24
Q
  1. beta oxidation: occurs in
A

mitochondrial matrix

25
Q
  1. beta oxidation: action
A

removes 2 carbon atoms at a time to form acetyl-CoA, NADH+H, and FADH2 units from the activated FA

26
Q

the last pair of carbons makes what

A

just acetyl CoA

27
Q
  1. mitochondrial oxidation: steps
A
  • acetyl CoA units enter krebs cycle
  • NADH+H and FADH2 enter the ETC
28
Q

fat breakdown is directly associated with

A

O2 uptake

29
Q

what must be available to accept electrons in ETC

A

O2

30
Q

number of acetyl CoA =

A

of carbons / 2

31
Q

number of NADH+H and FADH2 =

A

(# of carbons/2) - 1

32
Q

rate limiting enzyme for mobilization of FFA

A

HSL

33
Q

strength of HSL activation is dependent upon

A

intensity & duration of exercise, fitness level, & time since last food consumption

34
Q

strongest stimulators of HSL activation

A

catecholamines (inc during exercise)

35
Q

NEP/EP also stimulate breakdown of

A

CHO

36
Q

rate limiting enzyme for fat oxidation in muscle

A

CAT - it controls the amount of FA entering the mitochondria for oxidation

37
Q

how does exercise effect circulating FFA levels

A

inc by 10-20 fold

38
Q

best way to mobilize and use stored fat is to

A

exercise

39
Q

without sufficient ____ to interact with ____ the krebs cycle slows

A

OXA; acetyl-CoA

40
Q

depleting muscle glycogen effect

A

dec muscle max aerobic power output

41
Q

fat burns in

A

the flame of CHO

42
Q

low intensity uses primarily

A

fat

43
Q

high intensity uses primarily

A

CHO

44
Q

as training inc, the crossover point moves in what direction

A

to the right

45
Q

as exercise intensity increase reliance of fat ___ while reliance on CHO ____

A

decreases; increases

46
Q

even though high intensity exercises uses a smaller relative percentage of fat ….

A

you burn more calories, so you most likely burn more fat with higher intensity than you do with lower

47
Q

as exercise duration increases reliance on fat ___ while reliance on CHO ____

A

increases; decreases

48
Q

changes in lipid metabolism are related to ___ ___ rather than exercise intensity

A

exercise volume

49
Q

1st training related change

A

inc # of mitochondria and inc activity of enzymes w/in the mitochondria
- which inc kreb’s, ETC, and beta oxidation enzymes, thus inc oxidation of fat

50
Q

2nd training related change

A

inc fatty acyl-CoA synthesis

51
Q

3rd training related change

A

inc levels of HSL and CAT, which improve cellular availability and transport of FA

52
Q

4th training related change

A

inc TG storage and oxidation within the muscle

53
Q

5th training related change

A

inc FA uptake by the muscle

54
Q

how does training increase FA uptake by the muscle

A

capillary density inc in tissue, thus blood flow inc and better exchange of FA and O2

55
Q

6th training related change

A

improved cardiorespiratory system that enhances O2 delivery to the muscle

56
Q

why is enhancing o2 delivery to the muscle key

A

more oxygen, more quickly means you reach steady rate exercise more quickly and you have less reliance on anaerobic metabolism
- Less lactate production (less pH disruption & less stress on the system)

57
Q

7th training related change

A

all of these changes lead to CHO sparing
- delay in onset of fatigue
- can exercise longer and harder and use more fat compared to pre training