Homeostasis and control of blood glucose

Define homeostasis

The maintenance of a constant internal environment

Why could an increase in temperature be a problem

H bonds in tertiary structure of proteins may break so tertiary structure changes and protein can no longer carry out function

-No ES complex

Why could a decrease in temp be a problem

Particles may not have enough KE for reactions to occur

Substrate and AS collide

Rate of reaction too slow less ES complexes

why could a deviation in blood PH be a problem

H bonding and ionic bonding in proteins will change

Change in tertiary structure snd function of proteins

Why could an increase in blood glucose concentration be a problem

Increase in blood glucose,decreases water potential of blood

More water leaves cells and moves into the blood

Cells dehydrate and shrivel

Why could a decrease in blood glucose concentration be a problem

Decrease in blood glucose

Lack of glucose available for cells so less respiration.

-increases water potential more water absorbed into cells could lead to cells bursting

What is negative feedback

Where a change triggers a response which reduces the effect of a change

What is positive feedback

Where a change triggers a response which increases the effect of a change

Why are there separate mechanisms involving negative feedback

Control in different directions

Allows a greater degree of control

Why can cause blood glucose concentration to increase or decrease

Increase-eating drinking carbohydrate rich food

Decrease-exercising

What is glycogenesis

Conversion of glucose to glycogen

What is glycogenolysis and where does it take place

Conversion of glycogen to glucose

In liver

What is gluconeogenesis

Glucagon binds to receptors

Causes enzymes to be activated so amino acids and fatty acids and glycerol are converted into glucose

Liver

Describe what happens when blood glucose concentration is too high

Detected by BETA cells in the pancreas

Beta cell release insulin

Insulin travels in blood

Insulin binds to receptors on target cells

More glucose transporter proteins become embedded in the cell membrane and open

More glucose is absorbed into the cells

Insulin activates enzymes which convert glucose to glycogen

Describe what happens when blood glucose concentration is too low

Detected by alpha cells in pancreas’s

Alpha cells release glucagon

Glucagon travels in the bloood

Binds to receptors on target cells in liver and muscles

Adéntrate cyclase is activated and converts ATP to cAMP

cAMP activated protein kinase

Protein kinase activates other enzymes which convert glycogen to glucose or/amino acids and fats to glucose

Describe the effect of adrenalin on glycogen breakdown

Adrenalin travels in the blood

Binds to receptors on target cell in liver and muscles

Adenylate Cyclase is activated and converts ATP to cAMP

cAMP activates protein kinase

Protein kinase activates other enzymes which convert glycogen to glucose

What is the difference between the effects of glucagon and Adrenalin

Adrenalin-glycogenolysis

Glucagon-glycohenolysis and glyconeogenesis

What is the primary and secondary messenger in the secondary messenger model

Primary- glucagon and adrenalin

Secondary-cyclic AMP

What are type one and two diabetes caused by

1-autoimmune disease

2-risk factors usually obesity diet high in carbs

Why can blood sugar not be regulated in type 1 diabetes

Beta cells destroyed

No insulin produced

Why can blood sugar not be regulated in type 2 diabetes

Abnormal insulin receptors which cannot respond to insulin

Glucose transporters do not come to cell surface membrane and open

Glucose cannot be absorbed into the cell

How is type 1 and 2 diabetes controlled

1-insulin injections,controlled diet and sugar intake regular excersise

2-diet aims to keep blood glucose constant. Regular exercise ,loose weight