homeostatis

Question 1

explain the importance of painting the right core body temp

Answer 1

temp affects enzyme activity and enzymes control rate of metabolic reactions

Question 2

what affect does increasing temperature have on metabolic reactions

Answer 2

as it increases as does the rate of M reactions because more heat means more kinetic energy, so molecules move faster and so substrate molecules are more likely to successfully collide with enzymes active site’s, so the reaction takes place.

Question 3

what happens to metabolic reactions when temp is too high

Answer 3

essentially they stop. the rise is temperature makes the enzyme vibrate more- this vibration breaks some of the hydrogen bonds that hold the enzyme in it’s 3d shape changing the active site so it’s no longer complementary to the substrate it is thereby denatured - no longer a functioning catalyst.

Question 4

what happens to metabolic reactions if the temp is too low?

Answer 4

slow RoR due to reduced enzyme activity

Question 5

what is negative feedabck

Answer 5

the mechanism that restores the level of change within the homeostatic system using receptors, hormonal and nervous communication, and effectors to restore the set point.

Question 6

why is negative feedback sometimes not enough to return levels to the set point

Answer 6

change may be too big for defectors to counteract. e.g a huge drop in temp caused by a prolonged exposure to cold weather may be too large to counteract.

Question 7

what is positive feedback

Answer 7

changes that trigger a positive mechanism- which amplifies the change. effacers respond to further increase the level away from the set point. (not an element of homeostastis- as it’s not maintaining a constant internal env).

Question 8

when might PF be useful? and example

Answer 8

to rapidly activate processes in the body- for example during the formation of a blood clot after an injury, platelets become activated and release a chemical- this triggers more platelets to be activated. so they very quickly form a blood clot at the site of injury (this process ends when negative feedback is used to detect the blood clot has been formed).

Question 9

how is negative feedback used to control blood glucose concentration

Answer 9

if higher:

• beta cells (receptors) detect increase
• so release insulin
• increased uptake of glucose by effector cells
• enters through glucose transport proteins in CSM
• glucose is converted to glycogen (glycogenesis)

If lower:
-alpha cells (receptors) detect decrease
-so release glucagon
-increased conversion of glycogen to glucose (glycogenolysis)
increased conversion of amino acids and lipids to glucose (gluconeogenesis)
glucose leaves cells by facilitated diffusion through glucose channels