Homeostasis

Homeostasis: maintenance of the internal environment, to keep it stable, as changes in the external environment occur.

Homestasis is important for 3 main reasons: temperature, pH, and blood glucose concentrations. This is because all of these have an affect on the rate of metabolic reactions in the body. 

Temperature:

• Increase in temp means an increase in the kinetic energy of molecules, inclusing substrate and enzymes. This means they are more likely to collide, and form enzyme-substrate complexes. However, if the temperature gets too high, the hydrogen bonds in an enzymes active site break, and therefore change. The enzyme is now denatured, and therefore cannot function. the rate of metabolic reactions therefore decreases. 
• If the temperature gets too low, enzyme activity is reduced, and therefore the rate of metabolic reactions decreases. 
• The optimum temperature in the human body is 37 degrees. 

Blood pH:

• if the blood pH gets too high, the ionic and hydrogen bonds that hold the enzymes active site together break. This changes the shape of the active site, and so the substrates can no longer fit into the enzyme and form enzyme-substrate complexes. this means the rate of metabolic reactions decreases. 
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