Energy release from macronutrients Flashcards
1
Q
what regulates energy metabolism
A
- ADP levels
- conversion of ADP->ATP
- increased ADP levels gets ball rolling
2
Q
macronutrients supplying energy
A
- carbs
- fats
- proteins
3
Q
carbohydrates
A
- primary function is to supply energy for cellular work
- breakdown of 1 molecule glucose yields about 686 kCals of energy
- -bonds of ATP conserve roughly 263 kCals of energy
- -remainder lost as heat
- oxidation of one glucose molecule yeilds a total of 32 ATP molecules
4
Q
basic nutrition concept: carbs
A
daily recommendation of carbs
- sedentary 70kg person: 300g or 40-50% of total calories
- physically active: 400-600g or 60% of total calories
- athletes: 70% of total calories
5
Q
carbs and exercise
A
intensity and duration determine the fuel mixture during exercise
- high intensity exercise
- -one hour of high-intensity exercise decreases liver glycogen by 55%
- -two hours of high-intensity exercise almost depletes liver and muscle glycogen (85% VO2 max)
- moderate and prolonged exercise
- -fat serves as the main energy substrate
- -intermuscular fat, adipose tissue
6
Q
relation of glucose and FFA in exercise
A
- presence of glucose decreases FFA use
- always going to use glucose/glycogen first when present in system
- sustain increased intensity levels for long time when glucose loaded
7
Q
fats
A
- complete oxidation of one triacylglycerol molecule produces about 460 ATP molecules
- -via beta oxidatoin
- stored fat is most plentiful source of potential energy
- fat becomes the primary fuel for exercise and recovery when glycogen is depleted
- supplys roughly 30-80% of energy for work
8
Q
daily recommended lipid intake
A
- a diet should contain 20% of its total calories from lipids
- most americans=30-35%
9
Q
fat used as energy
A
-longer duration exercise
low intensity
-as exercise continues, energy stores shift
10
Q
basic nutrition concepts: lipids
A
- light to moderate exercise: energy comes from fatty acids
- moderate intensity exercise: energy comes from equal amounts of carbs and lipid supply
- high intensity exercise: carbs, primarily muscle glycogen is the preferred source of energy
11
Q
division of 460 atp from triglycerol
A
441 from b oxidation and citric acid
1 molecule of glycerol=19 glycolysis and citric acid
-need mitochondria for breakdown fats
12
Q
basic nutrition concepts: proteins
A
- amino acids=building blocks of body
- essential vs no essential
- typically not used as source of energy for exercise
- -extreme activity demands will resort to using protein for source of energy
13
Q
proteins
A
- after the removal of nitrogen (deamination) the remaining carbon skeletons enter the metabolic pathway to produce ATP aerobically
- -glucogenic amino acids-serve as the intermediates for glucose synthesis via gluconeogensis
- -ketogenic amino acids-serve as the intermediates acetyl CoA or acetoacetate
- protein breakdown results in water loss
14
Q
protein sources
A
- complete proteins: fish, eggs, milk, poultry
- incomplete proteins: nuts, vegetables, dry beans, cereals
15
Q
daily recommended protein intake
A
- .83g of protein per kg of body mass
- stress, disease and injury increase protein requirements
- athletes can consume between 1.4-1.7 grams per kg of body mass
