Respiration

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Respiration
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Custard powder experiment

• Did the food contain energy?
• What kind of energy did it have to start with?
• What kinds of energy was this released as?

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(No Transcript)
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Comparing energy in carbohydrates,proteins and
fats
Use different types of food to calculate which
will give the most energy
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Results
Food Material Mass of food (g) Starting temperature of water (0C) Finishing temperature of water (0C) Temperature rise (0C)
Carbohydrate
Protein
Fat
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Calculating energy in food

• A given amount of any substance always requires
  the same amount of energy to produce a particular
  increase in temperature.
• 1000g of water needs..4.2 kJ to make its
  temperature rise by 1 oC

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Calculating the energy content of foods

• The formula to calculate the energy release is
• 4.2 x M x T
• Now calculate the energy content of your foods

M mass of water (g)
Trise in temperature ( C)
1000
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Calorimeter
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Gases and respiration

• A Living Peas B Dead Peas
• Burn a lighted splint in each gas jar.

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Do other organisms respire?
breathing and respiration
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• 1 Which type of energy does food contain?
• 2 What is this energy converted to by other
  organisms? Give at least 3 examples.
• (i)
• (ii)
• (iii)
• 3 What name is given to the process by which
  organisms release energy?
• 4 What kind of energy is always released in
  respiration?

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The Chemistry of Respiration
energy and mitochondria clip
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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

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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
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Structure of ATP
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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.

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Energy from respiration
Enzymes
Energy Rich bond formed
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Summarised as
ADP Pi ATP
The whole process is under the control of enzymes
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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) .

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ATP
Enzymes
Energy released to do work
ADP
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Summary
The whole process is an enzyme controlled
reaction.
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Aerobic Respiration

• Aerobic respiration respiration with oxygen.

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glucose OXYGEN energy carbon dioxide
water(to make ATP)
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Aerobic respiration happens in 2 stages

• Stage 1 Glycolysis
• glyco lysis
• glucose splitting

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In glycolysis, a glucose molecule is broken down
into pyruvic acid.
glucose
series of enzyme controlled reactions
energy released to make small quantity of ATP (2
molecules)
pyruvic acid
Glycolysis does not require oxygen
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Stage 2 Breakdown of pyruvic acid

• The pyruvic acid made in glycolysis (stage1)
  still contains a lot of energy
• It can only be broken down to release the rest
  of the energy in the presence of oxygen.

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pyruvic acid
energy released to make large quantity of ATP (36
molecules)
series of enzyme controlled reactions
carbon dioxide water
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ATP production summary
glucose
2 ADP 2 Pi 2 ATP

pyruvic acid
36 ADP 36 Pi 36 ATP
carbon dioxide water
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Summary of ATP production

• Stage 1 and 2 release all the chemical energy in
  one molecule of glucose to make a total of 38 ATP
  molecules.
• 2 molecules ATP from glucose ? pyruvic acid
• 36 molecules ATP from pyruvic acid ? carbon-
  dioxide water
• Total 38 molecules ATP

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Anaerobic Respiration(in animals)

• anaerobic in the absence of oxygen

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In low oxygen conditions or during heavy
exercise, when not enough oxygen can be supplied,
muscle cells swap to anaerobic respiration
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glucose
glycolysis still happens as it does not require
oxygen
2 ADP 2 Pi 2 ATP

pyruvic acid
in absence of oxygen pyruvic acid is turned into
lactic acid.
lactic acid
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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.
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Summary
glucose
pyruvic acid
oxygen debt e.g. during hard exercise
oxygen debt repaid during recovery time
lactic acid
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Anaerobic Respiration in plants

• The same process occurs in plants and yeast in
  low oxygen conditions, e.g. muddy, flooded soils.

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glucose pyruvic acid
2 ADP 2 Pi 2 ATP
glycolysis still happens, producing 2 ATP
molecules

This time in absence of oxygen, pyruvic acid is
turned into carbon dioxide and ethanol
This is irreversible
ethanol carbon dioxide
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Comparison of aerobic and anaerobic respiration
Aerobic respiration Anaerobic Respiration Anaerobic Respiration
Aerobic 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
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Task

• Prepare a series of PowerPoint slides which show
  the importance of anaerobic respiration in the
  brewing and bread-making processes.
• Prepare a couple of slides to show the role of
  anaerobic respiration in the production of cheese
  and yogurt.
• Pages 4 -14 of your textbook will help you with
  these tasks if you are finding it difficult to
  find information on the internet.

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