Respiration D. Crowley, 2007

Respiration  To know the equation for respiration

Respiration  What do you know about respiration?  What is needed to live?  Do all organisms require the same thing?  In pairs, discuss any facts you know in the next two minutes  What do you know about respiration?  What is needed to live?  Do all organisms require the same thing?  In pairs, discuss any facts you know in the next two minutes

Respiration “Respiration is breathing in and out” “Plants photosynthesise but animals respire” “During respiration, oxygen is produced” “During respiration, energy is produced”  Although these comments may sound correct, every single one is wrong  These are common misconceptions, ‘banana skins’ of the SATs “Respiration is breathing in and out” “Plants photosynthesise but animals respire” “During respiration, oxygen is produced” “During respiration, energy is produced”  Although these comments may sound correct, every single one is wrong  These are common misconceptions, ‘banana skins’ of the SATs

Respiration  Respiration takes place in the cells (it is not “breathing in and out”)  Respiration is the release of energy (from glucose) in our cells  Animals and plants respire  In the light plants respire, but produce the oxygen for this to occur by photosynthesis - the carbon dioxide they produce via respiration is used for photosynthesis  In the dark plants respire, producing carbon dioxide  Respiration takes place in the cells (it is not “breathing in and out”)  Respiration is the release of energy (from glucose) in our cells  Animals and plants respire  In the light plants respire, but produce the oxygen for this to occur by photosynthesis - the carbon dioxide they produce via respiration is used for photosynthesis  In the dark plants respire, producing carbon dioxide

Equation  Remember, in a reaction: reactants  products glucose + oxygen  carbon dioxide + water + (energy) C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + (energy)  Respiration is the process of converting glucose to energy, occurring in every cell  Remember, in a reaction: reactants  products glucose + oxygen  carbon dioxide + water + (energy) C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + (energy)  Respiration is the process of converting glucose to energy, occurring in every cell

Testing  How could you test for respiration? What could you measure to prove it was taking place and at what rate?  During respiration the gas carbon dioxide is produced - testing for this would show if respiration occurred, and at what rate  The test for carbon dioxide is to use limewater (it goes cloudy)  Water is also produced - we could measure this (how much we exhale)  Energy is also released during respiration = which is used by our cells (however it is difficult to test this, but you could monitor the activity of the organism (the heat released))  How could you test for respiration? What could you measure to prove it was taking place and at what rate?  During respiration the gas carbon dioxide is produced - testing for this would show if respiration occurred, and at what rate  The test for carbon dioxide is to use limewater (it goes cloudy)  Water is also produced - we could measure this (how much we exhale)  Energy is also released during respiration = which is used by our cells (however it is difficult to test this, but you could monitor the activity of the organism (the heat released))

Can Dead Cells Respire?!  Your task is to find out if dead cells respire  Using yeast cells (one batch alive, the other dead) write down if you think dead cells will be able to respire + your reasons  Carry out the experiment, measuring the heat of both the live and dead cultures, and see if carbon dioxide is produced (look for the limewater going cloudy / see if any carbon dioxide bubbles are released)  Your task is to find out if dead cells respire  Using yeast cells (one batch alive, the other dead) write down if you think dead cells will be able to respire + your reasons  Carry out the experiment, measuring the heat of both the live and dead cultures, and see if carbon dioxide is produced (look for the limewater going cloudy / see if any carbon dioxide bubbles are released)

Results  Hopefully you found only live cells respire!  In this experiment we measured the products (energy & carbon dioxide produced (+ we could have measured the water produced))  However, we could have measured the reactants (how much oxygen / glucose was used)  Remember: respiration is the process of releasing energy from glucose, requiring oxygen  Why is it so important glucose is carried all around the body?  Respiration converts glucose into energy - every cell in the body respires to release energy, meaning every cell in the body needs access to glucose!  Hopefully you found only live cells respire!  In this experiment we measured the products (energy & carbon dioxide produced (+ we could have measured the water produced))  However, we could have measured the reactants (how much oxygen / glucose was used)  Remember: respiration is the process of releasing energy from glucose, requiring oxygen  Why is it so important glucose is carried all around the body?  Respiration converts glucose into energy - every cell in the body respires to release energy, meaning every cell in the body needs access to glucose!