| What is Homeostatis | the maintenenace of as constant internal environment |
| Importances of temperature constant | If the temperature was too low:
Enzyme rate of reactions would decrease due to decreased kinetic energy. This causes less ES complexes to form.
Homeostasis ensures that the internal temperature is maintained. This allows optimal enzyme reactions to occur; processes such as respiration occur continuously.
If the temperature is too high:
Hydrogen and ionic bonds in the enzyme break. This alters the specific tertiary structure and alters the active site shape. The substrate is no longer complementary so ES complexes do not form. |
| Importance of keeping ph constant | optimum ph for salivary amylase 7/8
optimum ph for pepsin 1/2
deviation from optimum temp causes enzymes to denature |
| Importance keeping blood glucose levels are constant | maintaining water potential so cells don't shrink or burst
if gluclose is low less energy
if blood wp maintained then more hydrated |
| What is Negative feedback | when normal level changes , receptors detect change and communicate through via nervous or hormonal system , effectors respond
THE CHANGE IN SYSTEM IS BROUGHT BACK TO NORMAL |
| What is positive feedback | amplifies the change when normal level is changed |
| What is GLYCOGENESIS | Glyco - glycogen genesis - formation
formation of glycogen |
| Glycogenolysis | GLycogen lysis - hydrolysis
hydrolysis of glycogen |
| Gluconeogenesis | gluco- glucose neo- new genesis - formation
formation of new glucose molecules |
| Hypoglycaemia | Hypo- low Gly- glucose Aemia -blood
low blood glucose |
| Hyperglycaemia | Hyper - higher
gly - clucose
aemia -- blood
high blood glucose |
| insulin activates glycogenesis how | ALPHA glucose joined by codensation reaction , realeasing water
glycosidic bonds are formed
processes carried out by enzymes |
| Glycerol + amino acids to glucose is what process | Gluconeogensesis |
| Glucose to glycogen | glycogenolysis |
| How does insulin regulate blood glucose levels | Blood glucose levels INCREASE after food is eaten (food digested and glucose absorbed in ileum)
The pancreas detects the INCREASE in blood glucose. The beta cells of the pancreas release INSULIN
Insulin is released into the blood and moves to the liver.
Insulin binds to the specific insulin receptor proteins in the liver cell membrane.
This Causes an increase in glucose channel proteins in the liver cells membrane so more glucose moves from blood into the liver cells by FD
Enzymes are activated
enzymes join glucose molecules together to form glycogen (glycogenesis )
excess glucose molecules are converted to fat
these negative feedback mechanisms decrease blood glucose levels back to normal |
| What happens blood glucose levels decrease (not eating ) | Blood glucose levels DECREASE (not eating/fasting/exercise)
The pancreas detects the DECREASE in blood glucose. The alpha cells of the pancreas release GLUCAGON
Glucagon is released into the blood and moves to the liver.
Glucagon binds to the specific Glucagon receptor proteins in the liver cell membrane.
This activates the second messenger model. Binding of glucagon activated adenylate cyclase (enzyme) which converts ATP in cAMP. cAMP activates protein kinase A (enzyme) which activates a cascade of enzyme reactions. The enzymes hydrolyse glycogen into glucose (glycogenolysis)
The glucose moves out of liver cells through channel proteins in the liver cell membrane and into the blood. This increases the blood glucose level.
. Gluconeogenesis also occurs – new glucose molecules produced from amino acids/glycerol.
6. These negative feedback mechanisms INCREASE the blood glucose levels back to normal. |
