Energy systems

describe the role of ATP

ADP binds to a phosphate group in an endothermic reaction to form ATP

ATPase breaks the bond of the final phosphate group to release energy in an exothermic reaction to re-form ADP

ATP is the body’s energy currency

define a coupled reaction

the products from one reaction are used in another

describe the ATP-PC system

High levels of ADP stimulate creatine kinase to break down PC bonds in an exothermic reaction to release one phosphate

The phosphate is used in the ATP re-synthesis cycle in an endothermic reaction

type of reaction, fuel, site of reaction, enzymes, ATP yield, by-products, duration + activity intensity/duration for ATP-PC system

type of reaction - anaerobic

fuel - PC

site of reaction - sarcoplasm

enzymes - creatine kinase

ATP yield - 1 per cycle

by-products - no fatiguing by-products

duration - 3-10 seconds

activity intensity/duration - high intensity/very short duration

advantages of ATP-PC system (4)

doesn’t require oxygen

PC stores readily available in muscle

no fatiguing by-products

provide energy for high intensity activity

disadvantages of ATP-PC system (3)

short duration compared to LA + aerobic

low ATP yield compared to LA + aerobic

limited fuel source in body

describe the lactic acid system

High levels of ADP stimulate GP to break down glycogen into glucose in an exothermic reaction

PFK breaks down glucose into pyruvic acid in an exothermic reaction which releases 2 phosphates

LDH breaks down pyruvic acid into lactic acid in an exothermic reaction

The 2 phosphates are used in the ATP re-synthesis cycle in an endothermic reaction

type of reaction, fuel, site of reaction, enzymes, ATP yield, by-products, duration + activity intensity/duration for LA system

type of reaction - anaerobic

fuel - glycogen

site of reaction - sarcoplasm

enzymes - GP, PFK, LDH

ATP yield - 2 per cycle

by-products - lactic acid as a fatiguing by-product

duration - 10-90 seconds high intensity, 10 seconds to 3 minutes moderate intensity

activity intensity/duration - moderate-high intensity/short-moderate duration

advantages of LA system (3)

higher ATP yield than ATP-PC

shorter chain of reactions than aerobic

large glycogen store in muscle

disadvantages of LA system (3)

lower ATP yield than aerobic

lactic acid as fatiguing by-product

longer reaction than ATP-PC

give the three parts of the aerobic system

glycolysis

Kreb’s cycle

electron transport chain

describe glycolysis

High levels of ADP stimulate GP to break down glycogen into glucose in an exothermic reaction

PFK breaks down glucose into pyruvic acid in an exothermic reaction which releases 2 phosphates

The phosphates are used in the ATP re-synthesis cycle in an endothermic reaction

Pyruvic acid is added to coenzyme A in an endothermic reaction to produce acetyl CoA

describe the Kreb’s cycle

Acetyl CoA is added to oxaloacetic acid in an endothermic reaction to produce citric acid

Citric acid feeds into the Kreb’s cycle

The Kreb’s cycle produces 2 phosphates, H+ ions, CO2 + more oxaloacetic acid

The oxaloacetic acid keeps the cycle turning

The phosphates are used in the ATP re-synthesis cycle in an endothermic reaction

describe the electron transport chain

The H+ ions from Kreb’s are added to NAD + FAD in an endothermic reaction to produce NADH + FADH

NADH + FADH feed into the ETC

The ETC produces a H+ ion which produces water + an electron which produces 34 phosphates

The phosphates are used in the ATP re-synthesis cycle in an endothermic reaction

type of reaction, fuel, site of reaction, enzymes, ATP yield, by-products, duration + activity intensity/duration for aerobic system

type of reaction - aerobic

fuel - glycogen (or FFAs)

enzymes - GP, PFK, coenzyme A, (lipase)

ATP yield - 38 per cycle

by-products - CO2, H2O (no fatiguing by-products)

duration - 3 minutes-2 hours

activity intensity/duration - low-moderate intensity/moderate-long duration

advantages of aerobic system (3)

large glycogen/FFA stores

larger ATP yield than ATP-PC + LA

no fatiguing by-products

disadvantages of aerobic system (3)

longer chain of reaction than ATP-PC + LA

requires oxygen

not effective for explosive actions

define energy continuum

how energy systems interact to provide energy for ATP re-synthesis

describe the factors that affect the energy continuum (6)

intensity + duration - long duration/low intensity = aerobic, short duration/high intensity = anaerobic

O2 transport + supply - O2 available = aerobic, O2 not available = anaerobic

fuel availability - high intensity + no PC = LA, high intensity + PC = ATP-PC, low intensity + no PC = aerobic, low intensity + no glycogen = aerobic but fats burned, low intensity + no glycogen/fats = ATP-PC

fitness level (aerobically fit) - FFAs burned faster so used first, store glycogen to use LA at end of race

fitness level (anaerobically fit) - ATP-PC extended so less reliant on LA, LA tolerance extended so less reliant on aerobic

enzyme activation levels - short duration + can stimulate creatine kinase = ATP-PC, short duration + can’t stimulate creatine kinase = LA, long duration + can’t stimulate GP = aerobic with FFAs (use lipase instead) for trained/ATP-PC for untrained

energy system threshold - under 10 seconds = ATP-PC, 10 seconds-3 minutes = LA, 3 minutes-2 hours = aerobic

describe OBLA + how it affects the energy continuum

high lactate levels of over 4 mmol/L

denatures enzymes, causes muscular fatigue, body collapses (increases VR, increase O2 intake so starts aerobic system to clear LA

when OBLA is high aerobic system is always used

define intermittent exercise

intensity alternates

describe factors affecting the energy continuum in intermittent exercise

player’s position - GK = ATP-PC/aerobic, C = LA

structure of game - short + frequent breaks (e.g. basketball) = LA, longer + less frequent breaks (e.g. rugby) = aerobic

coach’s strategy - high pressing = anaerobic, zone marking = aerobic

level of competition - low level = aerobic, high level = anaerobic