Energy Sources Flashcards
Energy
Capacity to do the work
kCalorie
Heat necessary to raise the
Temperature of 1 kg of water 1 deg C (if it is just calorie= 1 g of water 1 deg C)
Work
force x distance
What is energy needed for?
- Mechanical Movements
- Protein synthesis
- Storage of fuels
Carbohydrate
4kcal/gram
60%of calories
Fat
9kcal/gram
20% of calories
Protein
4kcal/gram
10-15% of calories
Six Categories of Nutrients
Carbohydrates, lipids,
Proteins, vitamins, mineral, and water
Forms of energy
Chemical
Electrical (signals)
Heat (muscle contraction)
Mechanical (body moves)
Forms of carbohydrates:
Monosaccharides
Disaccharides
Polysaccharides:
Polysaccharides:
starch, cellulose, glycogen
Disaccharides
maltose, sucrose
Monosaccharides
glucose and fructose
Glycogenesis
formation of glycogen from glucose
Glycogenolysis
breaking down of glycogen into glucose
2 fats important for metabolism
fatty acid
triglyceride
Role of Lipid in the body
Energy source and reserve
Protection of vital organs
Thermal insulation
Vitamin carrier
Essential amino acids (9)
Must be ingested in food; cannot be synthesized
Nonessential amino acids
Can be synthesized by body
Catabolic reaction
breaking down of substrate into molecules
Anabolic reaction
forming of product from molecules
Aerobic Metabolism
Oxygen required
Generates energy, CO2, & water
When is aerobic metabolism used?
Most commonly involves carbohydrate & fat (60/40)
Used at rest & during long-duration, lower intensity activity
Anaerobic Metabolism
No oxygen required
Generates energy, CO2, & lactic acid
When in anaerobic metabolism used?
Major energy source during high-intensity, short-duration activity
Examples: sprinting & weight lifting
Energy source of anaerobic metabolism?
carbs
ATP-PC System
Energy source for activities requiring much energy per second
Examples: sprinting, lifting a heavy weight
Can only provide energy for short time
Only small amount of ATP in cells; must be replenished quickly
Blood glucose in liver:
100 grams
Blood glucose in muscle:
350 grams
Rate limiting enzyme in break down of glycogen?
PFK (glucose to pyruvic acid)
LDH (pyruvic acid to lactic acid)
Where does anaerobic glycolysis take place?
cytoplasm
Where does aerobic metabolism take place?
mitochondria
Where are enzymes located?
cristae (inward folds and convolutions)
What is pyruvic acid broken down into?
2 carbon acetyl group. (Acetyl Co-A)
What does the Krebs’s cycle do?
removal of H atoms
How many ATP are produced in the Krebs’s cycle?
36
Break down of lipids:
beta oxidation
What part of the lipid is used in glycolysis?
glycerol
Break down of protein?
deamination
Fastest system?
ATP-PC system
Slowest system?
aerobic
Power for ATP-PC system?
3.6
Power for anaerobic glycolysis?
1.6
Power for aerobic?
1.0
Lactic acid during rest?
500mg (10mg/dl of blood)
Resting metabolic rate
3.5ml of O2/kg/min
1 liter of oxygen consumption produces :
5 Kcal of energy
RQ for glucose/carbs
1
RQ for fat
0.7
RQ for protein
0.8
RQ is
V carbon dioxide/V of oxygen
Work and oxygen
1kgm=1.8 ml of oxygen
Oxygen debt
oxygen taken in above resting values after exercise
Steady-state:
all energy needed is provided by aerobic metabolism; constant level of work (debt not felt)
Onset of blood lactate accumulation (OBLA):
exercise intensity at which a specific blood lactic acid concentration occurs
Lactate threshold in untrained:
occurs at 50% to 60% of max oxygen consumption
Lactate threshold in trained:
65% to 80% of max oxygen consumption
What is hitting the wall and what does it trigger?
Depletion of glycogen stores
increase in fat metabolism
At rest, what is ATP derived from?
33% of ATP is derived from carbs & 66% from fat
What is the body’s lactic acid tolerance?
60-70g
How much lactic acid does glucose break down into?
180 g
Max VO2
as the maximal rate at which oxygen can be consumed.
MET
A minimum level of energy required to sustain the body’s vital functions in the resting state
Determinants of oxygen uptake
Pulmonary ventilation Diffusion of oxygen Cardiac performance Skeletal vascular bed Extraction of oxygen by contracting skeletal muscle
How much does VO2 max decline per decade after the age of 25?
9%
