Chapter 3 - Bioenergetics Flashcards
Saliva
- Provides lubrication
- Breaks down carbohydrates with enzyme amylase
Protein Breakdown
- Broken down through churning and stomach acids/enzymes
- Broken down into amino acids called peptides
- Also broken into di and tripeptides
Carbohydrate Breakdown
- Small intestine
- Enzymes (Amylase)
- Broken into simple sugars (glucose)
Dietary Fat Breakdown
- Small intestine
- Enzymes (Lipases)
- Broken into fatty acids and monoglycerides
Bioenergetics
The study of how energy flows in the human body
Energy
Ability to do physical work
Metabolism
The sum of all chemical reactions in the body that use or create energy
Homeostasis
Demand for energy is met by supply of ATP, all body functions can occur with ease because the body is in a state of balance and stability
Aerobic metabolism
Sum of anabolic and catabolic process that occur in an aerobic context (using oxygen)
Anaerobic metabolism
Sum of anabolic and catabolic process that occur in an anaerobic context (not using oxygen)
Anaerobic Systems
- No oxygen
- Intense exercise when body has no time to get enough oxygen to body to produce ATP
- Created within the cytosol of the cell
ATP-CP (Phosphagen) System
- Up to 10 seconds of energy
- CP is stored 4-5 times more than ATP
- Phase 1: ATP splits forming ADP and P and energy
- Phase 2: Creatine kinase enzyme is used and CP splits, releasing to provide energy and reform ATP from ADP
Anaerobic (Glycolytic) System
- Up to 2 minutes at max intensity
- Cytoplasm: Glucose produces two ATP, Glycogen produces three ATP
- Three carbon compound called pyruvate is formed
- Pyruvate breaks down into lactic acid
- Lactic acid lowers cellular PH, making the molecule more acidic. Lowers speed and strength of muscle
- If exercise exceeds two minutes the muscle will shut down or blood will be able to deliver adequate oxygen, allowing for aerobic system to produce additional ATP
Lactate Threshold
When more lactic acid is formed than the body can metabolize
Lactic Acidosis
The point at which lactic acid causes muscle failure
Adaptations to Lactic Acid
- Muscle cells can be trained to produce less lactic acid by increasing glycolytic enzymes by 10%-25%
- Cells eventually become more efficient at working with lactic acid as well
Aerobic Systems
- Oxygen is available
- Mitochondria uses either glucose or fat for fuel to create ATP
Mitochondria
The cellular structures with specialized enzymes to assist in aerobic metabolism use either glucose or fat for fuel to create ATP
Aerobic (Glycolytic System)
- More than two minutes, moderate intensity - works well for long, continuous, moderate to low intensity exercise
- ATP and Pyruvate are generated from Glucose/glycogen
- Instead of pyruvate creating lactic acid, it enters chemical reactions called the Krebs Cycle and Electron Transport Chain
- With this oxygen, the cell can make more ATP (One glucose = 38 ATP)
- Waste (Carbon Dioxide, heat, and water)
Fatty Acid Oxidation System
- Low intensity, more than two minutes
- Most efficient. One unit of fatty acid creates 100 or more ATP
- Fatty acid is high energy but difficult to metabolize
- Waste (Carbon Dioxide, heat, and water)
- Used during rest due to low intensity, low demand for energy and sufficient oxygen
Energy System: at Rest
Aerobic metabolism of fatty acids
Energy System: at the Beginning of Exercise (slow build up)
Aerobic system will continue to be used
Energy System: at the Beginning of Exercise (Intermediate or high build up)
- Stored ATP used
- CP may be used to create more ATP until aerobic or anaerobic glycolysis system kicks in
- This shows importance of a good warm up (increased HR and respiration) - if not lactic acid will build up
Energy System: During Steady State Exercise
- Once oxygen meets demand, aerobic system kicks in
- For super long exercise, the presence of adequate glucose and glycogen may be limiting, pushing the emphasis towards fatty acid oxidation.(if intensity is low enough)
