Question

Scientists studied soybean plants grown in sunlit, controlled-environment chambers with a carbon dioxide (CO2) concentration of 700 μmol CO2/mol of air. The CO2 concentration in the chambers was approximately double that of normal concentrations of environmental CO2 . Photosynthetic rate is measured by the amount of CO2 exchanged in an area of leaf surface over time. The rate is directly influenced by the activity of the plant enzyme rubisco. During photosynthesis, rubisco fixes atmospheric carbon into an organic molecule as one of the first steps in the Calvin cycle. Scientists measured the amount of carbon fixation that occurred in the leaves of soybean plants grown at each temperature shown in Table 1.

T (C) Carbon Fixation
25 91
30 96
35 93
40 104
45 71
50 59

Describe the effect on an enzyme of an increase in environmental temperature above the optimum temperature range of the enzyme.

Answer 1

Answer:

This simply  illustrates the  effects of temperature on the activity of enzymes(in this case Rubisco). Generally temperature increase affect the activity of enzymes  by affecting the rate of collusion of the enzymes's active sites with the substrates,(in this case GP)

Explanation:

at  25 degree, the rate of reaction is very low because less colluision  takes place between the active sites of the enzymes rubisco and the subtrate,, therefore less enzyme subtrate-complex, to form enzyme- product -complex, and therefore the product C02 (91)  occurs,

At 30 degree more collision occurred between the active sites  of the enzymes and substrates, thus the volume of CO2 fixed increaseed to 96 .

This increases to the 104 at 40 degree  which is the optimum temperature of Rubisco.

Beyond the optimum of 40 degree, the  3D structure of enzyne Rubico vibrate energetically,The hydrogen bonds holding the 3D shape of the enzymes are broken down, Therefore,the shapes of the active site is lost. Thus Rubisco lost its specificity, and it is  said to be denature. Therefore the concentration of CO2 fixed dropped progressively, as the temperature increases.To 71 at 45 degree to 59 at 50 degree(complete denature) Thus enzymes becomes denatured with increases in temperature.