Unit 6 - Energy systems Flashcards
What are the 3 Key Energy (Macro-) Nutrients?
Proteins, Carbohydrates, fats
What is each macro-nutrient broken down into?
Proteins - Amino acids
Carbohydrates - Glucose, glycogen
Fats - Fatty acids
How many calories per gram does each yield?
Carbs - 4.1 cal/gram
Proteins - 4.3 cal/gram
Fats - 9.3 cal/gram
What is the role of Carbs?
- Most abundant organic substance
- Primary source of energy
- Come from veggies, fruit, and grains like bread and pasta
- Is composed of glucose (glycogen)
- Glucose is stored in the skeletal muscles and liver as glycogen and when needed for activity, can be easily transported by the blood throughout the body
Where is glucose stored?
It is stored within skeletal muscles in the body, ready to be released when and transported by the blood when needed for activity
How many ways is ATP re-synthesized?
Two ways, aerobically and anaerobically
What is aerobic respiration?
- In the presence of oxygen (O2)
- All of its metabolic activity will involve O2
- Occurs in the mitochondria
- Leads to the complete breakdown of glucose
What is ANaerobic respiration?
- Anaerobically (without oxygen)
- Without the use of oxygen (O2)
- None of its metabolic activity will involve O2
- Utilises chemicals and enzymes; occurs in the muscle fibre
- Short-lived
What is the ATP-PC system?
The ATP-CP system is the system that is responsible for very short (i.e. 1-2 repetitions), explosive movements. This energy system is only good for about 6-10 seconds of activity. Using cars as an analogy, the ATP-CP system would be your nitrous boost
What is another name for ATP-PC system?
The ATP-PC (adenisine-triphosphate phosphocreatine) system is also known as the phosphagen system
Key aspects of the ATP-PC system
- Relies solely on the action of stored ATP and phosphocreatine (Phosphocreatine (PC) is a readily accessible compound stored in the muscles)
- Phosphate is broken off of PC to resynthesize ATP
this system yields enough ATP for 10–15 seconds of energy because there is only a small reservoir of PC. - Provides highest rate of ATP synthesis
- The full replenishment of PC requires ATP and occurs during the recovery period (2-5 minutes). It occurs rapidly and is achieved mainly as a result of supplies of ATP being created during aerobic processes.
- Suited for power events such as 50m, 100m, high jump, weight lifting, which only last a few seconds and require a large burst of energy.
- There are no by-products in this system
What is the Glycolysis System?
- Second anaerobic energy pathway – good backup due to plentiful glucose/ glycogen levels that are normally in the body
- Also known as the EMP system
- Provides additional 1–3 minutes in high-level performance
- Glycolysis transfers energy from glucose and glycogen to rejoin ADP and phosphate to make ATP
- Yields twice as much ATP (2 molecules of ATP)
- By-product of this system is lactic acid (LA)
- This system is better suited for medium to high intensity activities – 400m, 800m, hockey shift
What does the glycolysis system rely on for re-synthesis?
2 ATP
What by-products are there in the glycolysis system?
- By-product of this system is lactic acid (LA)
- 2 ATP molecules and 2 Pyruvate
What events/activities is the glycolysis system best suited for?
- This system is better suited for medium to high intensity activities – 400m, 800m, hockey shift
How does the Cori Cycle work?
- Lactate is transported by the blood to the liver where most of it is converted back to glucose, from which glycogen is formed (gluconeogenesis) – one-sixth is given off as C02.
- The Cori Cycle is the process by which lactic acid is converted to pyruvate for future conversion to glucose and glycogen. In effect, lactate re-enters the cycle as an energy source.
What is the Aerobic system?
Cellular respiration is the third energy system and it contains 3 sub sections
- Glycolysis
- Krebs cycle
– Electron transport chain
- This system uses glucose, glycogen, fats, and protein to make ATP
- Lasts 90-120 seconds and beyond
- The by-products are carbon dioxide (C02) and water H20
- In presence of 02 this system can sustain activity for very long periods of time or until other physiological limits are reached
- This system used by our bodies to sustain endurance type activities – marathon, soccer
- This system involves molecular activity in the mitochondria of the cells, referred to as “cellular respiration”. Fats are the predominant energy source in exercise lasting longer than 20 minutes (proteins are used during starvation).
- Produces 36 ATP molecules for every glucose molecule, nearly 20X the anaerobic system.
Cellular respiration involves 3 sub-pathways:=
- Glycolysis:
The first stage is the same as the anaerobic-lactic system except that in presence of 02, pyruvic acid (3 carbons) is converted (oxidized) to acetyl CoA (2 Carbons) instead of lactic acid.
Acetyl CoA then enters the Krebs cycle (citric acid cycle) which is the central pathway for the metabolism of fats and proteins. (2 ATP) - Krebs Cycle (Citric Acid Cycle):
Highly complex process involving 8 chemical reactions.
2 ATP molecules are produced here along with compounds capable of storing high-energy electrons.
These electrons are sent to a process within the mitochondria known as electron transport chain. - Electron Transport Chain:
Final stage of aerobic respiration; extremely complicated process that produces large amounts of ATP (32) are produced with CO2 and H20 as the by-products.
Free radicals (highly reactive molecules) may also be by-products as the electrons pass down the chain and these may contribute to long-term muscle fatigue.
What does the aerobic system rely on for re-synthesis?
O2
What events/activities is the aerobic system best suited for?
- This system used by our bodies to sustain endurance type activities – marathon, soccer
What are the 3 sub sections of the Aerobic System?
Glycolysis, krebs, Electron transport chain
How many ATP is produced in each aerobic system cycle?
36 ATP are produced
How many chemical reactions are there (if any) in the aerobic system cycle?
At least 22 reactions
Muscle Fibre Types
Fast twitch and slow twitch
Slow-Twitch Muscle Fibres
- Red or dark in colour.
- Generate and relax tension relatively slowly.
- Able to maintain a lower level of tension for long durations.
- Feature a type of enzyme called myosin ATPase found attached to the thick filaments (myosin) in the muscle fibre. The body uses myosin ATPase to provide instant energy for muscle contraction.
- Contain low levels of what are known as glycolytic enzymes, which permit the release of glycogen within muscles
- Contain high levels of oxidative enzymes.
- Produce lower tension and/or contraction levels over a longer period of time.
-Ideal for activities such as long-distance swimming, cycling, and running.
