respiration2 by Ax2xkCQ

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									Respiration
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?
Comparing energy in carbohydrates,
        proteins and fats



                    Use different
                    types of food to
                    calculate which will
                    give the most
                    energy
                         Results
   Food        Mass of   Starting        Finishing      Temperature
   Material       food   temperature   temperature of      rise (0C)
                 (g)       of water          water
                             (0C)           (0C)

Carbohydrate



  Protein



    Fat
     Calculating energy in food
►A given amount of any substance always
 requires the same amount of energy to
 produce a particular increase in
 temperature.

► 1000gof water needs………………..4.2 kJ
 to make its temperature rise by 1 oC
 Calculating the energy content of foods

► The  formula to calculate the energy
  release is
► 4.2 x M x T     M = mass of     T=rise in
                  water (g)        temperature
  1000                             ( °C)


► Nowcalculate the energy content of your
 foods
Calorimeter
       Gases and respiration




► A: Living Peas           B: Dead Peas
► Burn a lighted splint in each gas jar.
   Do other organisms respire?




breathing and respiration
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?
                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       Pi   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.
                     Energy from respiration




adenosine    Pi      Pi
                                 +
                                               Pi


                    Enzymes




 adenosine    Pi      Pi             Pi

                   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

► Theenergy is released when that bond is
 broken to release the third inorganic
 phosphate (Pi) .
adenosine    Pi     Pi           Pi

             ATP

                   Enzymes




adenosine    Pi     Pi
                             +
                                      Pi

            ADP          Energy
                         released
                         to do work
                        Summary


                             ATP
                             ATP


                                            energy
                                             (out)
 cellular
respiration
                                                          cell
                                                           cell
                                                         activities
cellular       energy                                    activities
respiration      (in)                       energy
                                              (out)
                            ADP + Pi




        The whole process is an enzyme controlled reaction.
  Aerobic Respiration

Aerobic respiration = respiration with
               oxygen.
glucose + OXYGEN       energy + carbon dioxide + water
                   (to make ATP)
Aerobic respiration happens in 2
            stages:

 Stage 1 – Glycolysis

     glyco    lysis



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


energy released to            series of enzyme
make small                   controlled reactions
quantity of ATP
(2 molecules)

                     pyruvic acid


      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 can only be broken down to release
the rest of the energy in the presence
of oxygen.
               pyruvic acid




series of enzyme              energy released
controlled                    to make large
reactions                     quantity of ATP
                              (36 molecules)


          carbon dioxide + water
ATP production – summary
        glucose

                      2 ADP + 2 Pi =
                      2 ATP

       pyruvic acid

                      36 ADP + 36 Pi =
                      36 ATP


  carbon dioxide + water
 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
  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
                      glucose
 glycolysis still
 happens as it does
                                   2 ADP + 2 Pi
 not require oxygen
                                   2 ATP

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




                    pyruvic acid
oxygen debt                        oxygen debt
e.g. during hard                   repaid during
exercise                           recovery time
                     lactic acid
Anaerobic Respiration
      in plants


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


 glycolysis still                            2 ADP + 2 Pi
 happens, producing
 2 ATP molecules                             2 ATP


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


              ethanol + carbon dioxide
         Comparison of aerobic and
           anaerobic 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    Lactic acid                        Ethanol and
                           dioxide                                      carbon
                           and water                                    dioxide
                            Task
► Prepare a series of PowerPoint slides which
 show the importance of anaerobic respiration
 in the brewing and bread-making processes.

► Preparea 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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