1. Energy Systems

2. MACRONUTRIENTS 1. Protein 2. Carbohydrate 3. Fat
These are our direct sources of energy for daily life, physical exercise and work
consumed in large amounts
There are 3 types:
1. Protein
2. Carbohydrate
3. Fat

3. PROTEIN directly involved in fundamental chemical processes of life
when ingested:
-broken down into 20 amino acids

6. PROTEIN directly involved in fundamental chemical processes of life
when ingested:
-broken down into 20 amino acids
- 9 essential amino acids  attained through food (body produces 11 others)
Complete protein – food that contains all amino acids
- meat, eggs, cheese and milk
Incomplete protein –foods containing one but not all essential amino acids
- vegetables and fruits

7. each gram of protein contains 4 Calories of energy
for every kilogram of body weight, an adult needs 0.8 grams of protein
necessary for growth and repair of all tissues, and a critical component of hormones, enzymes and the immune system

8. FAT insulate and protect vital organs
highest energy yield = 9 calories of energy per gram

9. Saturated Unsaturated -animal sources -LDL (low-density lipoproteins)
-high levels LDL increased cholesterol plaque on artery walls heart disease
Unsaturated
plant sources
high concentrations of high-density lipoproteins (HDL)
flushed out of body

10. CARBOHYDRATE
most accessible energy source for the body  is the most abundant organic substance in nature
GLUCOSE -produced by photosynthesis, stored as GLYCOGEN in human
each gram yields 4 Calories of energy
If not utilized, becomes fat

11. Complex (starch) Simple (sugars) -takes body longer to absorb
-80 % of total carb intake
-cereals, fruits, vegetables, legumes and pasta
absorb MUCH faster
refined white sugar, pop, candy, etc

12. ENERGY . . .but why is it important that we ingest carbohydrates?
ATP (Adenosine Triphosphate)
- 3 phosphates attached to adenosine

13. Fritz Albert Lipmann and Herman Kalckar, 1941
ATP  ADP + P +ENERGY

14. The question we will be answering is not how the body uses ATP, but rather how the body goes about resynthesizing ATP.
Energy Systems
2 methods for resynthesizing ATP
1. Anaerobic System
-without oxygen
-muscle fibre
-quick; powerful short activities
-These systems work together
-coexist and overlap
-all physical activity relies on some combination of these systems
2. Aerobic System
-with oxygen
-mitochondria
-several complex reactions
-endurance activities

15. ATP-PC pathway Glycolysis Cellular Respiration
What we are going to examine are the three metabolic pathways that make up these two systems.
ATP-PC pathway
Glycolysis
Cellular Respiration
METABOLISM

16. ATP-PC System PC + ADP  ATP + Creatine Anaerobic alactic
Without O2
No lactic acid
first and simplest of the 2 anaerobic pathways
Short, powerful energy bursts  seconds
PC + ADP  ATP + Creatine
Phosphocreatine
-high energy molecule
-phosphate used to convert ADP to ATP
-small stores
-highest rate of ATP synthesis
-sprinting, high jump, powerlifting

17. -the replenishment of PC for this system needs ATP
-once levels of PC are depleted, a new system must take over for the body to continue and also for the body to replenish its PC levels
Takes 2-5 minutes

18. Glysolysis Anaerobic lactic Produces lactic acid
-partial breakdown of glucose in cytoplasm
-plentiful in the human body
-holds useable energy (ATP)

19. C6H12O6 + 2ADP + 2Pi  2C3H6O3 + 2ATP + 2H2O
Although ATP production is rapid, glycolysis is a much more complex process
-11 separate biochemical reactions
-yields twice as much ATP as the ATP-PC system
-lasts 1-3 minutes
C6H12O ADP + 2Pi  2C3H6O ATP + 2H2O
Glucose
Lactate
-if O2 present, pyruvate (pyruvic acid)
-if insufficient O2, pyruvate lactic acid
- hi Lacid  low Glucose breakdown
-decrease muscle contraction
-burning sensation
-basically glycolysis transfers energy from glucose to rejoin phosphate to ADP
Total ATP count = 2

20. Cellular Respiration Glycolysis Aerobic
When sufficient O2 is present, the pyruvate left over from Glycolysis will move into a new, even more complex pathway. . .
Cellular Respiration
Aerobic
-complete breakdown of glucose in the mitochondria of cells
-kicks roughly 90 sec into activity and lasts for endurance activities
-fats and proteins also used as energy sources in this pathway
As a last resort
Exercise longer than 20 minutes
-involves 3 separate pathways:
Glycolysis
-same as before, but pyruvate  Acetyl CoA (2 ATP)
Kreb’s Cycle (citric acid cycle)
-Acetyl CoA enters the more complicated pathway
-series of 8 reactions; also site of fat and protein metabolism

21. The Kreb’s Cycle

22. Cellular Respiration Glycolysis Aerobic
When sufficient O2 is present, the pyruvate left over from Glycolysis will move into a new, even more complex pathway. . .
Cellular Respiration
Aerobic
-complete breakdown of glucose in the mitochondria of cells
-kicks roughly 90 sec into activity and lasts for endurance activities
-fats and proteins also used as energy sources in this pathway
As a last resort
Exercise longer than 20 minutes
-involves 3 separate pathways:
NADH = Nicotinamide Adenine Dinucleotide plus Hydrogen 
FAD = flavin adenine dinucleotide
Glycolysis
-same as before, but pyruvate  Acetyl CoA (2 ATP)
Kreb’s Cycle (citric acid cycle)
-Acetyl CoA enters the more complicated pathway
-series of 8 reactions; also sight of fat and protein metabolism
-2 ATP produced along with 6NADH and 2FADH

23. Electron Transport Chain
The third and most “profitable” sub-pathway is the final stage of cellular respiration
Electron Transport Chain
-occuring in the mitochondria, the ETC takes high energy electrons, found within FADH and NADH molecules, through a chainlike process
-this process creates VAST amounts of ATP with only CO2 and water as by products

24. C6H12O6 + 6O2 + 36ADP + 36Pi  6 CO2 + 36ATP + 6H2O
-video
The electron transport chain contributes a whopping 32 ATP to the cellular respiration process
C6H12O O ADP Pi  6 CO ATP + 6H2O
Glycolysis = ATP/glucose
Kreb’s Cycle = 2 ATP/glucose
ETC = ATP/glucose
36 ATP/glucose

25. Interplay of Energy Systems
-video
Copy 5.1: Three Energy pathways compared (p.86) into your notes

26. Lactic Acid
-we know that lactic acid is a painful by product of glycolysis when insufficient oxygen is present
-one of the main causes of stopping activity
Anaerobic threshold
(Blood lactate threshold)
Point at which a large increase in blood lactate occurs (compared to resting levels)
Onset of blood lactate accumulation (OBLA)
Rapid accumulation of blood lactate; always occurs after the lactate threshold

28. The longer it takes a person to reach their threshold, the more “endurance” they have
Elite endurance athletes will have a high lactate threshold
Untrained individuals will have a low lactate threshold
Therefore, the lower your LT, the less efficient your energy systems are working, or the poorer your energy systems are

29. The Cori Cycle We can’t just think of lactic acid as a bad thing
Remember that blood lactate levels don’t ALWAYS increase
Therefore the body MUST have a way of ridding itself of lactic acid
takes lactic acid (lactate) and converts it to pyruvate in the liver
the pyruvate is then converted to glucose/glycogen and re-enters the energy pathways, allowing further production of ATP
Better endurance athletes will have a greater ability to convert their lactic acid

30. So what is the difference between these two athletes?
What allows one athlete to excel at running for 5 hours and another to excel at running for 10 seconds?

31. MYOGLOBIN Muscle Fibre Types
In general there are 2 types:
Slow-twitch m uscle fibres: -dark in in colour
-low levels of ATPase (instant energy) and glycolytic enzymes (promote glycogen release)
-high levels of oxidative enzymes
-lower tension/contraction over longer periods of time
-most active during endurance activities
MYOGLOBIN
(Oxygen storage)
Myoglobin is the difference. The amount of myoglobin (amount of ability to store oxygen) will determine if FT or ST
Fast-twitch muscle fibres: -paler colour
-high levels ATPase and glycolytic enzymes
-large amounts of tension with relatively low endurance levels
-activate 2X’s faster than slow twitch fibres
-most active for fast, powerful activities

32. Type I –Slow Oxidative (SO)
There are two main muscle fibres, but researchers are starting to lean towards three different types:
Type I –Slow Oxidative (SO)
Type IIa –Fast Oxidative Glycolytic (FOG)
Type IIb –Fast Glycolytic (FG)
Strong research evidence, that with consistent aerobic training, the body can convert type IIb fibres into type IIa
-that is, fast twitch muscles fibres can become an intermediary fibre that acts as both fast twitch and slow twitch
-no evidence for Type II  Type I

33. Tonic versus Phasic muscles
The function of a muscle is a pretty good indicator of its fibre make up.
-muscles that create power and speed
-mainly type II  fast twitch fibres
-biceps brachii
-muscles that maintain posture and stability
-mainly type I  slow twitch fibres
-little explosiveness, considerable endurance
-soleus

34. Read page 222, “Why are East African Distance Runners so Dominant.”
From the reading, find and write down the most important points, that could help you write a research paper on the topic of ENERGY SYSTEMS.