Biology GCSE (1)


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What is respiration?

Respiration means breaking down glucose to release energy.

Where does respiration happen?

Body cells are where action happens

Glucose----> Oxygen----> Carbon dioxide + water + Energy 

Where do we get glucose from ?


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Where do we get the oxygen come from?

From the air we breathe in

What happens to carbon dioxide and water?


Carbon dioxide gets excreted through the lungs water gets excreted through the kidneys

What do we use energy?

  • Working your muscles
  • transporting chemicals
  • absorbing food 
  • sending messages along nerves 
  • building cells for growth
  • keeping your body temp constant
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Aerobic respiration is the break down of glucose using oxygen 

Anaerobic respiration is the breakdown of glucose without the use of oxygen 

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Anaerobic Respiration 

yeast                          ( fermentation)

Glucose---> Co2 + Alcohol + Energy


Lacitic Formation

Glucose--->lactic acid + energy

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Why does anearobic respiration start to take place?

Through long periods of exercise your muscles become fatigued and they stop contracting efficiently, when this happens your heart + lungs can't get enough oxygen to your muscle quicker enough. This causes your muscles to start to carry out Anaerobic respiration.

What molecule is produced during anearobic respiration in humans?             Lactic acid

Why do we need to get rid of this molecule?

lactic acid can slowly poison your muscles.This causes cramps  

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why do we carry on breathing faster and deeper after exercise ?

we need to breakdown the lactic acid, therefore by breathing in oxygen the laactic acid gets broken down.

What is an oxygen debt?

Extra oxygen. Our oxygen debt builds up after we exercise hard. It has to paid back straight away .

How do sprinters deal with the build up of lactic acid compared to long distance runners?

sprinters hold there breath during 100m race after wards they need to take in about 7litres of oxygen to get rid of lactic acid. Long distance runners run much slower they build up lactic acid in the early stage of the race, but get rid of it while running.

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Why does anaerobic respiration produce less energy than aerobic respiration?

Without oxygen glucose is only partly broken down into alcohol or lactic acid. A lot of energy remains in the molecules of alcohol + lactic acid.

Respiration takes place in all our cells. The fuel for respiration is glucose.

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