RespirationRespiration

The Chemistry of The Chemistry of RespirationRespiration

energy and mitochondria clip

Adenosine triphosphateAdenosine triphosphate

►The energy released during respiration The energy released during respiration is is notnot used directly by cells. used directly by 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 ) is

bonded to a third inorganic phosphate bonded to a third inorganic phosphate

(Pi) using the energy released from (Pi) using the energy released from

glucose. 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 bond when that bond is broken to release the third inorganic is broken to release the third inorganic phosphate (Pi) .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 Aerobic RespirationRespiration

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 33 stages:stages:

Stage 1Stage 1 – – GlycolysisGlycolysis (in (in cytoplasm)cytoplasm)

glycoglyco lysislysis

glucose splittingglucose splitting

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

energy released to make only 2 ATP and 2 NADH from NAD+

series of enzyme controlled reactions

pyruvic acid

glucose

Glycolysis does not require oxygen

But…if oxygen is present then….

Stage 2 – Stage 2 – Kreb’s Cycle Kreb’s Cycle

Happens in the mitochondrial matrixHappens in the mitochondrial matrix

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 the release the rest of the energy in the presencepresence ofof oxygenoxygen..

Energy carrying molecules NADH and FADH2

series of enzyme controlled reactions

pyruvic acid

carbon dioxide

Stage 2 – Kreb’s Cycle

ATP productionATP production – – summarysummary

8 NADH2 FADH2 2ATP

glucose

pyruvic acid

carbon dioxide + water

2 NADH2 ATP

GLYCOLYSIS

Kreb’s cycle

Summary of ATP Summary of ATP productionproduction

►Cellular respiration releases all the Cellular respiration releases all the chemical energy in chemical energy in oneone molecule of molecule of glucose to make a total of glucose to make a total of 3636 molecules molecules of ATPof ATP

3636 molecules ATP from pyruvic acid molecules ATP from pyruvic acid carbon- carbon- dioxide dioxide ++ waterwater

Total 36 molecules ATPTotal 36 molecules ATP

Anaerobic Anaerobic RespirationRespiration(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 to supplied, muscle cells swap 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=2ATP2 NAD+ to NADH

2 NADH toNAD+

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

in yeast, in yeast, microorganismsmicroorganisms

The same process occurs in The same process occurs in microorganisms and yeast in microorganisms and yeast in low oxygen conditions, e.g. low 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

NADH to NAD+

2 ADP + 2 Pi

2 ATP

Comparison of aerobic and Comparison of aerobic and anaerobic respirationanaerobic respiration

Aerobic Aerobic respirationrespiration

Anaerobic RespirationAnaerobic Respiration

in animalsin animals In microbes and yeastIn microbes and yeast

Oxygen required?Oxygen required? yesyes nono nonoGlycolysis occursGlycolysis occurs yesyes yesyes yesyesATP yieldATP yield 36ATP36ATP 2ATP2ATP 2ATP2ATPGlucose completely broke Glucose completely broke

down?down? yesyes nono nonoEnd productsEnd products Carbon Carbon

dioxide dioxide and and waterwater

Lactic Lactic acidacid

Ethanol Ethanol and carbon and carbon dioxidedioxide

TaskTask► Prepare a series of PowerPoint slides which Prepare a series of PowerPoint slides which

show the importance of show the importance of anaerobic anaerobic respirationrespiration in the in the brewingbrewing and and bread-bread-makingmaking processes. processes.

► Prepare a couple of slides to show the role Prepare a couple of slides to show the role of anaerobic respiration in the production of of anaerobic respiration in the production of cheese and yogurt.cheese and yogurt.

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