Energy Systems

Question 1

Aerobic system

Answer 1

exercise intensity is low, long duration and oxygen is available
s- produces lots of ATP (38 with glucose and 3x more with fats)
provides energy for long periods of times
no fatiguing by products
w- requires oxygen
- produces carbon dioxide

Question 2

Glycolysis

Answer 2

occurs in sarcoplasm of muscle cell
glycogen is broken down into glucose by glycogen phosphorylase
glucose broken down into pyruvate by PFK

Question 3

Krebs cycle

Answer 3

occurs in matrix of mitochondria
pyruvate combines with coenzyme A to form acetyl coenzyme A which can enter the Krebs cycle
fatty acids go through beta oxidation to form acetyl coenzyme A
acoA enters Krebs cycle and combines with oxaloacetate to form citric acid- hydrogen and co2 are given off
oxidation of citric acid
hydrogen is taken to ETC

Question 4

Electron transport chain

Answer 4

occurs in cristae of mitochondria
hydrogen atoms split into h ions and electron
electrons travel down ETC and pump H+ into membrane
H+ exit and release energy to resynthesise 34 ATP
H+ combine with e- and o2 to form water

Question 5

oxygen consumption

Answer 5

submaximal oxygen deficit- when there is not enough oxygen available at the start of exercise to provide energy aerobically
have to repay oxygen debt

Question 6

epoc

Answer 6

volume of oxygen consumed in recovery above the resting rate
fast replen stage- alactacid; restores ATP,PC stores, resaturates myoglobin with o2
uses 3 litres of o2, completed in 2-3 minutes
slow replen stage- lactacid; removes lactic acid and converted into protein, glucose or removed in sweat and urine, can be oxidised in mitochondria
uses 5-6 litres of oxygen, takes 1 hour/ several hours

Question 7

indirect calirometry

Answer 7

provides estimate of energy expenditure from amount of co2 produced and o2 used
enables us to find out the main substrate used for respiration

Question 8

lactate sampling

Answer 8

objective level of lactate in the blood
OBLA- 4mmol in blood (when lactate is produced)
higher lactate threshold = fitter athlete
lactate testing provides comparison for coach and athlete
lower lactate at same level= higher lactate threshold
obla is written as a % of vo2 max so higher vo2 max means higher lactate threshold

Question 9

Vo2 max test

Answer 9

vo2 max- max amount of o2 that can be utilised by the muscles per unit of time eg 1min
exercise performed on treadmill, bike etc from minimal effort to maximal
oxygen and carbon dioxide levels are recorded by direct gas analysis
vo2 max is reached: plateau in o2 uptake, max heart rate reached or volitional exhaustion

Question 10

Respiratory exchange ratio

Answer 10

ratio of co2 produced and o2 consumed so used as a measure of energy expenditure
determines which energy source is being used
RER closer to 1= carbohydrates
RER close to 0.7 = fats
RER above 1= anaerobic exercise
1 is more likely to produce lactic acid

Question 11

factors affecting lactate accumalation

Answer 11

fitness/trained status of performer- physiological adaptive changes in response to training eg greater capillary density
respiratory exchange ratio- closer to 1 means glycogen is being used so more likely to accumulate lactate
muscle fibre type- slow twitch can delay lactate accumulation
VO2 max- higher vo2 max means higher lactate threshold so delayed lactate accumulation
intensity of exercise- higher intensity means faster lactate accumulation
VFMRI

Question 12

vo2 max

Answer 12

maximum volume of oxygen that can be utilised by the muscles per unit of time
lactate threshold is written as % of vo2 max
higher vo2 max means performer can delay OBLA for longer
lactic acid can be broken down + prevents build up
high vo2 max means higher aerobic capacity
trained athletes can exercise for longer at high intensities as lactate threshold is higher % of vo2 max

Question 13

ATP PC system

Answer 13

ATP is broken down to release energy which forms ADP
as ADP levels rise, creatine kinase detects this
breaks down PC into phosphate and creatine
energy released here used to re synthesis ADP + Pi to form ATP
s- provides energy very quickly without oxygen
no fatiguing by products
re synthesised very quickly to allow high intensity exercise to happen again
w- takes 2-3 minutes to recover it fully
limited stores of PC
used up within 8-10 seconds

Question 14

lactic acid removed

Answer 14

during slow component of EPOC
is oxidised to form pyruvate 
then forms co2 and water
occurs in mitochondria 
stored in muscles and liver
converted to glycogen/glucose

Question 15

sub maximal exercise

Answer 15

at start of exercise, oxygen deficit is formed as we do not have enough o2 at the start of exercise to provide energy aerobically
provided anaerobically until the body can produce enough o2

Question 16

aerobic training

Answer 16

increases performer’s ability to transport oxygen
increased capillary density
increased avo2 difference so more o2 can be extracted by muscles

Question 17

epoc increase

Answer 17

maintenance of high hr and br
extra oxygen used to replenish atp and pc stores, restaurate myoglobin and remove la

increase in body temp keeps respiratory rate high and allows performer to take in more o2

Question 18

lactic acid system

Answer 18

provides energy/ atp when there is no oxygen
first 2-3 mins of high intensity exercise
(glycolysis occurs- glycogen to glucose to pyruvate)
incomplete breakdown of pyruvate into lactic acid
by lactate dehydrogenase
produce 2x atp molecules
s- provides energy at high intensity, in absence of o2
w- at very high intensity it is fatigued very quickly, produce LA which limits energy production
la reduces pH so enzymes in glycolysis are inhibited