9.1 Homeostasis

Question 1

what is ‘homeostasis’

Answer 1

the maintenance of a state of dynamic equlibirum in the body, despite changes in the external or internal conditions.

Question 2

why is it important that core temperature remains stable?

Answer 2

maintain stable rate of enzyme-controlled reactions.
temperature too low= enzyme and substrate molecules have insufficient kinetic energy (to collide)
temperature too high= enzymes denature

Question 3

why is it important that blood pH remains stable?

Answer 3

maintain stable rate of enzyme controlled reactions (and optimum conditions for other proteins)

acidic pH= H+ ions interact with H-bonds and ionic bonds in tertiary struycture of enzymes–> shape of active site changes so no ES complexes form.

Question 4

why is it important that blood water remains stable?

Answer 4

prevent osmotic lysis/crenation of cells

Question 5

define ‘negative feedback’

Answer 5

self-regulatory mechanisms return the internal envronment to optimum when there is a fluctuation

eg blood glucose regulation

Question 6

define ‘positive feedback’

Answer 6

a fluctuation triggers changes that result in an even greater deviation from the normal level.

eg childbirh