section 1 (2)Explain why the maintenance of a constant internal environment is important for optimal metabolic efficiency

Question 1

Why is the maintenance of a constant internal environment is important for optimal metabolic efficiency?

Answer 1

• enzymes require a specific set of pH and temperature conditions to function at an optimal rate
• enzymes control all metabolic processes and so if are not functioning at their optimal rate, the metabolic activity will not occur properly

Question 2

What is the effect of increased temperature on enzymes?

Answer 2

• increased temperature leads to increase enzyme activity until optimum temperature (more energy for an increase in random interactions)
• high temperatures denature enzymes; there is permanent damage to protein structure and hydrogen bonds in the enzymes
• partially denatured enzymes will regain shape after cooling
• completely denatured enzymes cannot correctly function again

Question 3

What is the effect of a change in pH on enzymes?

Answer 3

• enzymes are most effective in a certain pH range (1.5 to 2 in the mammalian stomach)
• extreme pH will denature enzymes

Question 4

What is the effect of a change in substrate concentrations?

Answer 4

• increased concentration of substrate will increase the rate of reaction until all enzyme active sites are occupied (saturation point)
• the reaction will then proceed at its maximum rate