1 earoicb 2 esptniirrao 3 xogney 4 lcguoes 5 reitabhng 6 gidsteeiv 7 arcbno oexiidd 8 gneery 9 ritoonmdhica 1 Aerobic 2Respiration 3 Oxygen 4 Glucose 5 Breathing 6 Digestive 7 Carbon dioxide 8 Energy 9 Mitochondria

Anaerobic respiration Learning objectives Write the equation for anaerobic respiration in animal cells. Explain the effect of lactic acid build up on muscle activity. Explain why anaerobic respiration is less efficient than aerobic respiration. Define the term oxygen debt. Write the equation for the Breakdown of lactic acid into carbon dioxide and water.

Aerobic respiration carbon dioxide glucose + oxygen  + water (energy) You know that…… carbon dioxide glucose + oxygen  + water (energy) +

Aerobic respiration Glucose + Oxygen Carbon Dioxide + Water + Energy Aerobic – ‘with oxygen’ Plenty of oxygen Efficient When able to completely digest food …but what happens when we are using energy faster than oxygen can be supplied?

Anaerobic respiration Glucose Lactic Acid + (some) Energy from the digestive system waste product not as much energy as with aerobic respiration Anaerobic – ‘without oxygen’ Not efficient Harmful waste product – causes cramp For short periods of time

Lactic acid can stop muscles within the body from contracting and relaxing. This can lead to fatigue and cramp. relaxation The lactic acid soaks the muscle cells and prevents the muscle cell from doing its job. contraction

This leaves us with a problem... If you want to consider the full impact of damage caused by the presence of lactic acid, just remember that the heart is made of muscle cells! This leaves us with a problem... if we want to do exercise YES NO We want the energy that anaerobic respiration produces But we don’t want the lactic acid waste product So the answer is for anaerobic respiration to be a ‘gap-fill’ during periods of very low / no oxygen availability.

Oxygen debt oxygen levels time rest aerobic exercise stops anaerobic exercise oxygen levels time Anaerobic respiration keeps our bodies going until we can breathe in more oxygen again. Whilst we are performing anaerobic respiration, our bodies are building up a ‘debt’ of oxygen.

The oxygen debt will have to be repaid when the exercise stops. Whilst we are performing anaerobic respiration, our bodies are building up a ‘debt’ of oxygen The oxygen debt will have to be repaid when the exercise stops. The oxygen breaks down (oxidises) the lactic acid into carbon dioxide and water. The process of anaerobic respiration which can then turn back into... In this way, the process of aerobic respiration can be converted into Respiration in exercise

Changes during a triathlon Before Start of swim Into swim Cycling Running Sprint finish After Body temperature (oC) 36.3 36.0 36.7 37.4 Heart rate (beats per min) 85 135 145 155 142 159 133 Breathing (litres per min) 3.2 6.9 7.2 7.6 7.9 8.3 Blood sugar (mg per 100 cm3) 100 80 120 106 94 83 114

Before Start of swim Into swim Cycling Running Sprint finish After Body temperature (oC) 36.3 36.0 36.7 37.4 Heart rate (beats per min) 85 135 145 155 142 159 133 Breathing (litres per min) 3.2 6.9 7.2 7.6 7.9 8.3 Blood sugar (mg per 100 cm3) 100 80 120 106 94 83 114 Before the race starts Helen tries to relax as much as possible. Her heart rate is low but the excitement of the coming race has already started to get adrenalin pumping around her body. This natural hormone is preparing her body for the race to come.

Before Start of swim Into swim Cycling Running Sprint finish After Body temperature (oC) 36.3 36.0 36.7 37.4 Heart rate (beats per min) 85 135 145 155 142 159 133 Breathing (litres per min) 3.2 6.9 7.2 7.6 7.9 8.3 Blood sugar (mg per 100 cm3) 100 80 120 106 94 83 114 As the swim starts Helen’s body reacts to the cold water and exercise, notice the slight drop in temperature but the increase in heart and breathing rates. Why has the blood sugar dropped slightly?

Before Start of swim Into swim Cycling Running Sprint finish After Body temperature (oC) 36.3 36.0 36.7 37.4 Heart rate (beats per min) 85 135 145 155 142 159 133 Breathing (litres per min) 3.2 6.9 7.2 7.6 7.9 8.3 Blood sugar (mg per 100 cm3) 100 80 120 106 94 83 114 She’s well into her swim now. Helen’s heart rate and breathing rate have both increased. Why? And what has caused the increase in her blood sugar level?

Before Start of swim Into swim Cycling Running Sprint finish After Body temperature (oC) 36.3 36.0 36.7 37.4 Heart rate (beats per min) 85 135 145 155 142 159 133 Breathing (litres per min) 3.2 6.9 7.2 7.6 7.9 8.3 Blood sugar (mg per 100 cm3) 100 80 120 106 94 83 114 Out of the water and onto her bike. This is a long slog to the next part of the race – the 40 km bike ride. Helen needs to pace herself to leave energy for the road race.

Before Start of swim Into swim Cycling Running Sprint finish After Body temperature (oC) 36.3 36.0 36.7 37.4 Heart rate (beats per min) 85 135 145 155 142 159 133 Breathing (litres per min) 3.2 6.9 7.2 7.6 7.9 8.3 Blood sugar (mg per 100 cm3) 100 80 120 106 94 83 114 The 10 km road race has started! Helen’s leg muscles are really beginning to ache now as lactic acid from anaerobic respiration begins to build up. Her breathing and heart rates increase even further but she must be careful not to push herself too far – or she won’t be able to finish.

Before Start of swim Into swim Cycling Running Sprint finish After Body temperature (oC) 36.3 36.0 36.7 37.4 Heart rate (beats per min) 85 135 145 155 142 159 133 Breathing (litres per min) 3.2 6.9 7.2 7.6 7.9 8.3 Blood sugar (mg per 100 cm3) 100 80 120 106 94 83 114 The end is in sight! Now its time to sprint to the finish line. Helen’s body cannot take this sort of strain for much longer – the last few hundred metres will be the hardest of the whole triathlon! Her heart rate is now higher than at any previous time in the race.

Before Start of swim Into swim Cycling Running Sprint finish After Body temperature (oC) 36.3 36.0 36.7 37.4 Heart rate (beats per min) 85 135 145 155 142 159 133 Breathing (litres per min) 3.2 6.9 7.2 7.6 7.9 8.3 Blood sugar (mg per 100 cm3) 100 80 120 106 94 83 114 And its over! Helen’s time was 2 hours 53 minutes! She’ll continue to breathe heavily for another 10 minutes or more as the lactic acid in her muscles is broken down. She’ll cool down slowly to help to prevent muscle pain.