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Respiration This Powerpoint is hosted on www.worldofteaching.comwww.worldofteaching.com Please visit for 1000+ free powerpoints
► Foods provide us with calories but they are not the form of energy used by cells. ► Food is broken down by enzymes in the digestive system to form glucose. ► Celllular Respiration in the mitochondria forms ATP from these sugars.
The Chemistry of Respiration energy and mitochondria clip
Adenosine triphosphate ► The energy released during respiration is not used directly by cells. ► Instead it is used to make a molecule called ATP which stores the energy until it is needed. ATP = Adenosine triphosphate
What does ATP do? ► ATP supplies energy for all the processes that need it. ► For example: ► movement ► chemical reactions ► growth. slow twitch/fast twitch investigation
Structure of ATP adenosine Pi
Formation of ATP ATP is made when another molecule called adenosine diphosphate (ADP) is bonded to a third inorganic phosphate (Pi) using the energy released from glucose. ATP is made when another molecule called adenosine diphosphate (ADP) is bonded to a third inorganic phosphate (Pi) using the energy released from glucose.
Pi adenosine Pi + adenosine Pi Enzymes Energy from respiration Energy Rich bond formed
Summarised as: ADP + Pi ATP The whole process is under the control of enzymes
The role of ATP ► ATP stores the energy in the third bond of the molecule ► The energy is released when that bond is broken to release the third inorganic phosphate (Pi).
Pi adenosine Pi + Energy released to do work ATP ADP Enzymes adenosine Pi
Summary 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 Respiration Aerobic respiration = respiration with oxygen.
glucose + OXYGEN carbon dioxide + water + ATP C 6 H 12 O 6 + O 2 ――> CO 2 + H 2 O + ATP
Aerobic respiration happens in 2 stages: Stage 1 – Glycolysis glyco lysis glucose splitting This stage occurs in the cytoplasm.
In glycolysis, a glucose molecule is broken down into pyruvic acid. This process requires 2 ATP to start the reaction. energy released to make 4 ATP (-2ATP+4ATP=2ATP) Net gain of 2ATP series of enzyme controlled reactions pyruvic acid glucose Glycolysis does not require oxygen
Stage 2 – Breakdown of pyruvic acid The pyruvic acid made in glycolysis (stage1) still contains a lot of energy. It moves into the mitochondria to continue the process. It can only be broken down to release the rest of the energy in the presence of oxygen. It can only be broken down to release the rest of the energy in the presence of oxygen.
energy released to make large quantity of ATP (~36 molecules) series of reactions, called The Kreb Cycle &Electron Transport Chain pyruvic acid carbon dioxide + water
ATP production – summary 34 ADP + 34 P = 34 ATP glucose pyruvic acid carbon dioxide + water 2 ADP + 2 P = 2 ATP
Summary of ATP production ► Stage 1 and 2 release all the chemical energy in one molecule of glucose to make a total of 36 ATP molecules. 2 molecules ATP from glucose pyruvic acid 2 molecules ATP from glucose pyruvic acid 34 molecules ATP from pyruvic acid carbon- dioxide + water 34 molecules ATP from pyruvic acid carbon- dioxide + water Total 36 molecules ATP
Anaerobic Respiration (in animals) anaerobic = in the absence of oxygen
In low oxygen conditions or during heavy exercise, when not enough oxygen can be supplied, muscle cells swap to anaerobic respiration
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 P 2 ATP
A build up of lactic acid produces muscle fatigue. Muscle fatigue makes muscles ache and contract less powerfully. A recovery period is needed. During this time more oxygen is taken in to convert the lactic acid back into pyruvic acid again. The volume of oxygen needed is called the oxygen debt.
Summary oxygen debt e.g. during hard exercise oxygen debt repaid during recovery time glucose pyruvic acid lactic acid
Anaerobic Respiration in plants The same process occurs in plants and yeast in low oxygen conditions, e.g. 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 P 2 ATP
Comparison of aerobic and anaerobic respiration Aerobic respiration Anaerobic Respiration in animals in plants and yeast Oxygen required? yesnono Glycolysis occurs yesyesyes ATP yield 36ATP2ATP2ATP Glucose completely broke down? yesnono End products Carbon dioxide and water Lactic acid Ethanol and carbon dioxide