energy systems

Question 1

ATP

Answer 1

Adenosine Triphosphate

Food we eat is stored in the body as glycogen = converted in ATP

Question 2

What does ATP release energy for when broken down?

Answer 2

• muscle contractions
• nerve transmission
• digestion

Question 3

How is ATP broken down?

Answer 3

Enzyme ATPase breaks ATP down into ADP (adenosine diphosphate) + releasing energy

Previously ATP made up of 1 adenosine + 3 phosphates

Question 4

ATP re synthesis

Answer 4

• ATP only lasts for 2-3 secs so stores are depleted quickly
• constantly re synthesised
• to re synthesise, the loose phosphate need to rejoin the ADP
• ATP resynthesis: ADP + P + energy = ATP
• stored in 3 systems

Question 5

3 energy systems

Answer 5

• ATP-PC
• glycolytic
• aerobic system

Question 6

ATP-PC system

Answer 6

• used during high intensity exercise
• lasts for 2 secs
• as ATP is used quickly, ADP + P stores build up
• triggers the enzyme creatine kinase to be released

e.g. gymnastics vault

Question 7

Describe how the ATP-PC system works

Answer 7

• Start with phosphocreatine (P + C)
• creatine kinase breaks down PC into P + C + energy
• energy is used to resynthesise ATP
• energy is used to resynthesise the phosphate with ADP
• we end up with 1 resynthesise dad ATP

Question 8

Glycolytic energy system - lactic acid

Answer 8

• system kicks in after 10 secs where PC + ATP levels have fallen
• enzyme GPP breaks down glycogen into glucose
• ADP and P levels rise which releases the enzyme PFK
• this enzymes breaks down glucose
• glucose is broken down to access energy to resynthesise ATP = anaerobic glycolysis
• anaerobic glycolysis results in the production of pyruvic acid
• once O2 levels have lowered too much (around 3 mins in) the enzyme LDL (low density lipoprotein) is released
• LDL helps convert pyruvic acid into lactic acid = accumulates + slows down ATP synthesis (which we don’t want to wait)
• caused by absence of O2
• lactic acid causes fatigue

e.g. 100m swim

Question 9

Role of lactic acid (glycolytic energy system)

Answer 9

• as lactic acid levels rise, pH in muscle cells decrease (increasing acidity)
• this inhibits enzyme activity = preventing further ATP resynthesis
• OBLA: The Onset of Blood Lactate Accumulation = the point at which blood lactate accumulation significantly rises

Question 10

Glycolytic energy system summary - Type of reaction

Answer 10

Anaerobic

Question 11

Site of reaction

Answer 11

Sarcoplasm

Question 12

Food fuel used

Answer 12

Glycogen/ glucose

Question 13

Enzyme

Answer 13

GPP, PFK, LDH

Question 14

ATP yield

Answer 14

1 glucose = 2 ATP

Question 15

By-products

Answer 15

Lactic acid

Question 16

Activity intensity

Answer 16

High

Question 17

Duration of system

Answer 17

Up to 3 mins

Question 18

Strengths

Question 19

Weaknesses

Question 20

Aerobic system

Answer 20

• aerobic energy system kicks in during low to moderate intensity activity

Question 21

3 stages of aerobic system

Answer 21

• aerobic glycolysis
• the Krebs cycle
• the electron transport chain (ETC)

Question 22

Aerobic glycolysis

Answer 22

• first stage
• PFK catalyses the conversion of glucose into pyruvic acid = releases energy to resynthesise 2 ATP
• process is maintained by GPP converting glycogen into glucose = more glucose available
• presence of O2 prevents pyruvic acid being converted into lactic acid
• instead goes through a link reaction catalysed by coenzyme A (produces Acetyl CoA) = alllws access to the mitochondria

Question 23

Mitochondria

Answer 23

A structure within the cell where aerobic respiration + energy production occur

Question 24

The Krebs cycle

Answer 24

• Acetyl CoA combined combines with oxaloacetic acid to form citric acid
• the citric acid is oxidised through a cycle of reactions = the Krebs cycle
• the Krebs cycle releases CO2 + hydrogen + enough energy to resynthesise 2 ATP
• all this occurs in the matrix of the mitochondria

Question 25

ETC

Answer 25

- electron transport chain (ETC) - the hydrogen atoms are carried through the ETC in the mitochondrial Cristae = carried by NAD + FAD (hydrogen carriers) - theyre split into ions (H+) and electrons (H-) - H+ ions are oxidised = released as H2O - H- electrons are carried by NAD and FAD (NADH2/ FADH2) - NADH2 releases energy for 30 ATP - FADH2 releases enough energy for 4 ATP

Question 26

The aerobic system + free fatty acids (FFA)

Answer 26

- glycogen is the main fuel for endurance performers - however, triglycerides or fats can also be metabolised aerobically as FFA’s allow us to conserve glycogen / glucose stores - the enzyme lipase is released (catalyses the breakdown of fats) = converted into FFA’s + glycerol - FFA’s are converted into Acetyl CoA c follow the path through the Krebs cycle + ETC

Question 27

2 factors that help us indicate which energy system is being used

Answer 27

- intensity of activity - duration of activity

Question 28

Energy continuum

Answer 28

2 Pic on iPad

Question 29

Intensity very high energy system

Answer 29

Intensity very High: duration < 10 secs E.g. jumpers, throwers, sprinters etc.. ATP-PC system will be predominant

Question 30

Intensity high: duration 10 secs - 3 mins

Answer 30

Intensity high: duration 10 secs - 3 mins E.g. 400m, 200m freestyle, competitive squash game Glycolytic energy system will be predominant

Question 31

Intensity low-moderate

Answer 31

Intensity low-moderate: duration > 3 mins E.g. marathon, triathlon, cross country skiing etc.. Aerobic energy system will be predominant

Question 32

Intermittent exercise

Answer 32

- intensity alternates either during interval training or between rest + work intervals during a game - leads to athlete switching between the 3 energy systems during the same game - point where an athlete moves from one energy system to another known as a THRESHOLD - e.g. defender in football while team is attacking (using a different energy system to when defending and other team attacking) Graph on ipad

Question 33

ATP-PC system switching to Glycolytic system EXAMPLE

Answer 33

Apply to netball GD getting an intercept 2 Pic on ipad

Question 34

Recovery periods: (ATP-PC)

Answer 34

Although PC stores are depleted quickly, also replenished quickly PC replenished: - 50% in 30 secs - 100% in 3 mins - useful for e.g. netball + basketball = time outs + play 4 quarters instead of 2 half’s (lots of bursts of speed, few periods of time where they’re out of play) - O2 stored in myoglobin can also be restored fully within 3 mins

Question 35

Recovery periods: (Glycolytic)

Answer 35

- as exercise duration increases, glycogen levels decrease - at same time = lactic acid levels increase - however, some lactic acid is removed during periods of low intensity exercise/ activity recovery = creates zig zag Pic on iPad

Question 36

Recovery periods: (Aerobic)

Answer 36

Endurance athletes often have breaks in play, providing the chance to rehydrate + replenish glycogen/ glucose levels through: - drinking water - glucose tablets - gels - bananas - isotonic drinks - e.g. jelly babies