Regulation of Carbohydrate/Fat Metabolism and Exercise Effects

Question 1

what are the fast fiber types

Answer 1

type 2 myosin a and b

Question 2

what are the slow fiber types

Answer 2

type 1 myosin

Question 3

what color are type 1 myosin fibers and why

Answer 3

redder in color due to the large amounts of myoglobin

Question 4

describe the contents of type 1 fibers

Answer 4

contain large numbers of oxidative enzymes, more mitochondria, and are surrounded by more capillaries

Question 5

describe the energy and fatigue properties of type 1 fibers

Answer 5

large capacity for aerobic metabolism and high resistance for fatigue

Question 6

where can type 1 fibers be found and what is their function

Answer 6

generally postural muscles and used for endurance

Question 7

what are type 2a fast oxidative fibers made of

Answer 7

a hydrid of type 1 and type 2

Question 8

describe type 2a fast oxidative fibers

Answer 8

red in color and contain large amount of mitochondria

Question 9

what respiratory pathway do type 1 fibers use to make ATP

Answer 9

aerobic metabolism

Question 10

what pathway do type 2a fibers use to make ATP

Answer 10

aerobic and anaerobic metabolism

Question 11

describe type 2b fast glycolytic fibers

Answer 11

white in color, low levels of myoglobin and few mitochondria

Question 12

what pathway do type 2b fast glycolytic fibers use to make ATP

Answer 12

anaerobic metabolism

Question 13

what can influence the composition of muscle fiber types

Answer 13

training and genetics

Question 14

what is the fatigue rate of the muscle fiber types in order of low fatigue to high fatigue rate

Answer 14

slow twitch, fast twitch oxidative, fast twitch glycolytic

Question 15

what is the energy source used during the first hour of exercise

Answer 15

muscle glycogen provides 50% of energy, muscle triglycerides and plasma free fatty acids are 25% each

Question 16

what is the energy source used during exercise in the second hour of exercise

Answer 16

blood glucose and plasma free fatty acids provide most as muscle glycogen and triglycerides are being depleted faster than they can be replaced

Question 17

what energy source is used during the 3rd hour of exercise

Answer 17

blood glucose and plasma free fatty acids

Question 18

what energy source is being used during hour 4 of exercise

Answer 18

blood glucose and plasma free fatty acids. muscle glycogen is fully depleted and muscle triglycerides provide less than 10% of energy needs

Question 19

which muscle fiber type provides more force

Answer 19

fast twitch

Question 20

what is maximal tetanic force

Answer 20

maximum force a muscle can generate

Question 21

what is specific force

Answer 21

max force divided by muscle cross sectional area, looks at how much the individual myofibril can contract

Question 22

what does myostatin or GDF8 do

Answer 22

inhibit muscle differentiation and growth

Question 23

what does loss of myostatin lead to

Answer 23

increased muscle size

Question 24

describe the myostatin protein

Answer 24

member of the TGF beta superfamily and binds to the activating type 2 receptor

Question 25

how does specific force change in loss of myostatin

Answer 25

it is lower because max force is the same but the muscle size is bigger

Question 26

what do endurance and resistance training result in

Answer 26

a shift from fast 2b myosin to 2a, although changes are small and do not result in a complete conversion

Question 27

describe sarcopenia and how to limit it

Answer 27

loss of muscle mass with aging. 2 phases: 10% lost from age 25-50 then rapid loss after age 50. regular exercise can limit or reduce age related muscle loss

Question 28

what happens to muscle mass in paralysis or disuse

Answer 28

atrophy

Question 29

explain the role of ATP in muscle contraction (power stroke)

Answer 29

myosin is attached to actin, as contraction takes place ADP and phosphate are released, ATP binds and muscle fiber returns to steady state with ATP back to ADP and Pi

Question 30

describe the structure of glycogen

Answer 30

-it is a glycoprotein -consists of a core protein "glycogenin" - highly branched structure made of glucose molecules connected through 1,6- and 1,4- glycosidic bonds

Question 31

what enzymes are involved in glycogen synthesis

Answer 31

branching enzyme and glycogen synthase

Question 32

what enzymes are involved in glycogen breakdown

Answer 32

glycogen phosphorylase and glycogen debranching enzyme

Question 33

explain how diets affect muscle performance

Answer 33

carbohydrate rich diets display longer or extended muscle performance times

Question 34

what is the cori cycle

Answer 34

muscle uses glucose in glycolysis for energy which makes lactate. lactate goes to the liver to be converted back to glucose to be used for energy again

Question 35

why are trigylcerides highly concentrated stores of metabolic energy

Answer 35

they are reduced and anhydrous

Question 36

what is the main reason muscles use glucose for energy instead of fatty acids

Answer 36

fatty acids require molecular oxygen and aerobic respiration is slower

Question 37

what substances stimulate lipolysis

Answer 37

glucagon, corticosteroids, ACTH, and catecholamines

Question 38

what inhibits lipolysis

Answer 38

insulin

Question 39

what are the 4 steps of beta oxidation of fatty acids

Answer 39

oxidation - hydration - oxidation - thiolysis

Question 40

what does EPO do

Answer 40

stimulates red blood cell production which would translate to a greater supply of oxygen to tissues but it also thickens blood and increases strain on the heart

Question 41

how many ATPs can you generate under aerobic conditions

Answer 41

38

Question 42

how mnay ATPs can you generate in anaerobic respiration

Answer 42

2

Question 43

what is carnitine used for

Answer 43

the transport of fatty acids from the cytosol into the mitochondria during the breakdown of lipids

Question 44

what are fat deposits used for

Answer 44

contain triglycerides used during porlonged exercise as muscle glycogen is depleted and energy demands cannot be met by glucose

Question 45

what is "hitting the wall"

Answer 45

a condition caused by depletion of glycogen stores in the liver and the muscles which causes sudden fatigue and reduction in energy

Question 46

in glycogen breakdown what are the terminal residues that are released

Answer 46

first residue is glucose, subsequent ones are glucose-1-P

Question 47

what do the terminal residues do after being released

Answer 47

glucose combines with glucose-1-p to form glucose-6-P which feeds into glycolysis

Question 48

how long do glycogen and glucose stores provide energy to sustain biological function

Answer 48

24 hours

Question 49

how long do triacylglycerol stores allow for survival

Answer 49

several weeks

Question 50

what do peripheral tissues do with fatty acids

Answer 50

-storage - exported as VLDL - or undergoes beta oxidation to enter krebs cycle

Question 50

what do peripheral tissues do with fatty acids

Answer 50

-storage - exported as VLDL - or undergoes beta oxidation to enter krebs cycle

Question 51

what substrate does each step of beta oxidation use

Answer 51

-oxidation: FAD - hydration: H2O - oxidation: NAD+ -thiolysis: CoA

Question 52

what does insulin do to ACC? glucagon?

Answer 52

insulin stimulates, glucagon inhibits