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Gas exchange and respiration

           the enzyme is found in tissues that have a high number of anabolic pathways, such
           as liver.  This form  produces  guanosine  triphosphate  (GTP). GTP is energetically
           equivalent to ATP. However, its use is more restricted. In particular, protein synthesis
           primarily uses GTP.
           The sixth step is the oxidation  of succinate  to form fumarate.  The conversion of
           succinate into fumarate involves removal of hydrogen and is catalysed by succinate
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           dehydrogenase. In this reaction FAD is reduced to FADH .
                                                                  2









                    The seventh step is the hydration of fumarate to malate. This reversibl  e reaction is catalysed

                The seventh step is the hydration of fumarate to malate. This reversible reaction is catalysed
                    by fumarase, which is also known as fumarate hydratase.
           The seventh step is the hydration of fumarate to malate. This reversible reaction is


                by fumarase, which is also known as fumarate hydratase.
               The seventh step is the hydration of fumarate to malate. This reversible reaction is catalysed
           catalysed by fumarase, which is also known as fumarate hydratase.


               by fumarase, which is also known as fumarate hydratase.






                    Eighth step is the oxidation of malate to form oxaloacetate. This reaction is catalysed by malate

           Eighth step is the oxidation of malate to form oxaloacetate. This reaction is catalysed

                    dehydrogenase and results in the production of oxaloacetate which is the starting compound of
                Eighth step is the oxidation of malate to form oxaloacetate. This reaction is catalysed by malate
           by malate dehydrogenase and results in the production of oxaloacetate which is the

                    the Kreb’s cycle. In this process, NAD is reduced into NADH .
                dehydrogenase and results in the production of oxaloacetate which is the starting compound of
                                                                   2

           starting compound of the Kreb’s cycle. In this process, NAD is reduced into NADH .
                the Kreb’s cycle. In this process, NAD is reduced into NADH .

                                                                2
               Eighth step is the oxidation of malate to form oxaloacetate. This reaction is catalysed by malate  2


               dehydrogenase and results in the production of oxaloacetate which is the starting compound of

               the Kreb’s cycle. In this process, NAD is reduced into NADH .
                                                                 2




                    It is important to note that glycolysis yields two pyruvate molecules, each of which enters the

           It is important to note that glycolysis yields  multiplied by two. Thus, the products of
                    Kreb’s cycle separately. Thus, for a molecule of glucose, there must be two Kreb’s cycles, and,
                It is important to note that glycolysis yields two pyruvate molecules, each of which enters the
           two pyruvate molecules, each of which  the  Kreb’s cycle are 6NADH , 2FADH ,
                Kreb’s cycle separately. Thus, for a molecule of glucose, there must be two Kreb’s cycles, and,

                                                                                   2
                    to avoid repetition, each component of the cycle must be multiplied by two. Thus, the products  2
           enters the  Kreb’s cycle separately. Thus,  4CO , 2ATP, and oxaloacetate molecules.
                    of the Kreb’s cycle are 6NADH , 2FADH , 4CO , 2ATP, and oxaloacetate molecules. The
                 to avoid repetition, each component of the cycle must be multiplied by two. Thus, the products
                                                     2
                                             2
                                                           2
                                                          2
           for a molecule of glucose, there must be  The transitory step, that is from pyruvate
                of the Kreb’s cycle are 6NADH , 2FADH , 4CO , 2ATP, and oxaloacetate molecules. The
               It is important to note that glycolysis yields two pyruvate molecules, each of which enters the
                                                       2
                                                 2
                                         2
                    transitory step, that is from pyruvate to acetate, yields 2NADH and 2CO molecules (Figure
                                                                            2
                                                                    2
           two Kreb’s cycles, and to avoid repetition,  to acetate, yields 2NADH and 2CO     2
               Kreb’s cycle separately. Thus, for a molecule of glucose, there must be two Kreb’s cycles, and,
                transitory step, that is from pyruvate to acetate, yields 2NADH and 2CO molecules (Figure
                                                                                 2
                    6.10 (a) and (b)).
                                                                2
                                                                         2
               to avoid repetition, each component of the cycle must be multiplied by two. Thus, the products
           each component of the  cycle must be  molecules (Figure 6.10 (a) and (b)).
                6.10 (a) and (b)).
               of the Kreb’s cycle are 6NADH , 2FADH , 4CO , 2ATP, and oxaloacetate molecules. The
                                         2
                                                        2
                                                  2
               transitory step, that is from pyruvate to acetate, yields 2NADH and 2CO molecules (Figure
                                                                  2
                                                                          2
                 Form Five Student’s Book
               6.10 (a) and (b)).                                                         315
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