The Chemistry of The Chemistry of RespirationRespiration

energy and mitochondria clip

Adenosine triphosphateAdenosine triphosphate The energy released during The energy released during

respiration is respiration is notnot used directly by used directly by cells.cells.

Instead it is used to make a molecule Instead it is used to make a molecule called called ATPATP which stores the energy which stores the energy until it is needed.until it is needed.

ATP = ATP = AAdenosine denosine ttriripphosphatehosphate

What does ATP do?What does ATP do? ATP supplies energy for all the ATP supplies energy for all the

processes that need it. processes that need it. For example: For example:

movementmovement chemical reactionschemical reactions growthgrowth..

slow twitch/fast twitch investigation

Structure of ATP Structure of ATP

adenosine Pi Pi Pi

Formation of ATPFormation of ATP

ATP is made when another molecule ATP is made when another molecule called adenosine called adenosine didiphosphate (phosphate (ADPADP) ) is bonded to a third inorganic is bonded to a third inorganic phosphate (Pi) using the energy phosphate (Pi) using the energy released from glucose. released from glucose.

Pi

adenosine Pi Pi +

adenosine Pi Pi Pi

Enzymes

Energy from respiration

Energy Rich bond formed

Summarised as:Summarised as:

ADP + Pi ATP

The whole process is under the control of enzymes

The role of ATPThe role of ATP ATP ATP storesstores the energy in the the energy in the thirdthird

bond of the moleculebond of the molecule

The energy is The energy is releasedreleased when that when that bond is broken to release the third bond is broken to release the third inorganic phosphate (Pi) .inorganic phosphate (Pi) .

Pi

adenosine Pi Pi +

Energy released to do work

ATP

ADP

Enzymes

adenosine Pi Pi Pi

SummarySummary

ATP

ADP + Pi

energy (out)

energy (in)

cellular respiration

cell activities

ATP

energy (out)

cellular respiration

cell activities

The whole process is an enzyme controlled reaction.

Aerobic RespirationAerobic Respiration

Aerobic respirationAerobic respiration = respiration with = respiration with oxygenoxygen..

glucose + glucose + OXYGEN OXYGEN energy + carbon dioxide + energy + carbon dioxide + waterwater

(to make ATP)(to make ATP)

Aerobic respiration happens in Aerobic respiration happens in 22 stages: stages:

Stage 1Stage 1 – – GlycolysisGlycolysis

glycoglyco lysislysis

glucose splittingglucose splitting

In glycolysis, a glucose molecule is broken down into pyruvic acid.

energy released to make small quantity of ATP(2 molecules)

series of enzyme controlled reactions

pyruvic acid

glucose

Glycolysis does not require oxygen

Stage 2 – Stage 2 – Breakdown of pyruvic Breakdown of pyruvic acidacid

The pyruvic acid made in glycolysis The pyruvic acid made in glycolysis (stage1)(stage1) still contains a lot of still contains a lot of energyenergy

It can only be broken down to It can only be broken down to release the rest of the energy in release the rest of the energy in the the presencepresence ofof oxygenoxygen..

energy released to make largequantity of ATP(36 molecules)

series of enzyme controlled reactions

pyruvic acid

carbon dioxide + water

ATP productionATP production – – summarysummary

36 ADP + 36 Pi =36 ATP

glucose

pyruvic acid

carbon dioxide + water

2 ADP + 2 Pi =2 ATP

Summary of ATP productionSummary of ATP production Stage 1 and 2 release all the chemical Stage 1 and 2 release all the chemical

energy in energy in oneone molecule of glucose to molecule of glucose to make a total of make a total of 3838 ATP molecules.ATP molecules.

22 molecules ATP from glucose molecules ATP from glucose pyruvic acid pyruvic acid 3636 molecules ATP from pyruvic acid molecules ATP from pyruvic acid

carbon- carbon- dioxide +dioxide + waterwater

Total 38 molecules ATPTotal 38 molecules ATP

Anaerobic RespirationAnaerobic Respiration(in animals)(in animals)

anaerobic = in the absence of anaerobic = in the absence of oxygenoxygen

In In lowlow oxygen conditions or oxygen conditions or during during heavy exerciseheavy exercise, when , when not enough oxygen can be not enough oxygen can be

supplied, muscle cells swap supplied, muscle cells swap to to anaerobicanaerobic respirationrespiration

glycolysis still happens as it does not require oxygen

in absence of oxygen pyruvic acid is turned into lactic acid.

pyruvic acid

lactic acid

glucose

2 ADP + 2 Pi

2 ATP

A build up of lactic acid produces A build up of lactic acid produces musclemuscle fatiguefatigue. .

Muscle fatigue makes muscles ache and Muscle fatigue makes muscles ache and contract less powerfully.contract less powerfully.

A recovery period is needed. During this A recovery period is needed. During this time more time more oxygenoxygen is taken in to convert the is taken in to convert the lactic acid back into pyruvic acid again.lactic acid back into pyruvic acid again.

The volume of oxygen needed is called the The volume of oxygen needed is called the oxygenoxygen debtdebt..

SummarySummary

oxygen debte.g. during hard exercise

oxygen debtrepaid during recovery time

glucose

pyruvic acid

lactic acid

Anaerobic Respiration Anaerobic Respiration

in plantsin plantsThe same process occurs in The same process occurs in

plants and yeast in low plants and yeast in low oxygen conditions, e.g. oxygen conditions, e.g. muddy, flooded soils.muddy, flooded soils.

glycolysis still happens, producing 2 ATP molecules

This time in absence of oxygen, pyruvic acid is turned into carbon dioxide and ethanol

glucose

pyruvic acid

ethanol + carbon dioxide

This is irreversible

2 ADP + 2 Pi

2 ATP

Comparison of aerobic and Comparison of aerobic and anaerobic respirationanaerobic respiration

Aerobic respiration

Anaerobic Respiration

in animals in plants and yeast

Oxygen required? yes no no

Glycolysis occurs yes yes yes

ATP yield 38ATP 2ATP 2ATP

Glucose completely broke down? yes no no

End products Carbon dioxide and water

Lactic acid Ethanol and carbon dioxide