3.6.4.1 Principles and negative feedback

Question 1

Why is it important that temperature and pH is maintained at a constant value? (optimum point)

Answer 1

small fluctuations may change tertiary structure of enzyme - affecting its ability to carry out its role

Question 2

Why is it important that water potential is kept constant?

Answer 2

changes may cause cells to burst/ expand or shrink - stops ability of cell to operate normally

Question 3

Why is it advantageous for organisms to be able to maintain a constant internal environment?

Answer 3

wider geographical range - increased likelihood of finding food, shelter as can survive in a range of habitats

Question 4

What is the optimum point?

Answer 4

point at which the system operates best

Question 5

What does a receptor detect?

Answer 5

stimulus (deviation from optimum)

Question 6

What is negative feedback?

Answer 6

when the change produced by the control system (effector) leads to a change in stimulus detected by receptor, which turns the control system off (i.e. negative feedback decreases the strength of the stimulus)

Question 7

Why is negative feedback important?

Answer 7

prevents ‘over-correction’ of response (hence ensures conditions do not deviate too far from optimum point)