Glycolysis and glucose oxidation Flashcards
describe what excessive glucose is
hyperglycaemic – too much can lead to damage as glucose is reactive and can react with things
describe what too little glucose is
hypoglycaemic – don’t have enough energy to function
- Glucose can be stored in limited quantities as glycogen
how much of the brain uses glucose
- At present the brain is using 60% of blood glucose
how many grams of glucose is circulating
- Current have 4g of glucose circulating
glucose is a
6 carbon sugar
how is glucose taken into cells
- by facilitated transport across the membrane
- GLUT transporters
what does GLUT 1 do
constitiuvie glucose transporter (low Km) found in all cells
why does GLUT 1 have a low Km
low Km – refers to the concentration at which something gets saturated, a low Km means it saturates at a low concentration, ,this means you can only transport a low amount of glucose
what does Glut 2
liver/pancreas uptake (high Km)can act as a glucose sensor in the liver and pancreas
why does Glut 2 have a high Km
High Km this is found in the pancreas where it is involved in allowing the pancreas to sense blood glucose, this means that it cannot get saturated so it can sense a high range of glucose concentrations
what does Glut 4 do
glucose uptake in muscle and adipose (low Km) cellular location is controlled by insulin
what are the two locations that Glut 4 exist
exists as vesicles inside cytoplasm or exists by fusing with the membrane via insulin action
describe how Glut 4 controls how much glucose the cell takes up
- exists as vesicles inside cytoplasm or exists by fusing with the membrane via insulin action
- By changing where it is in the cell membrane or vesicles controls the amount of glucose the cell takes up
- These allow you to control whether a cell is taking up glucose or not
- When glucose concentration is high promotes adipose and muscle to take up glucose
what is the amount of Glut 4 in muscle membrane effected by
by exercise – they what to take up more glucose to get that energy
describe the mechanism of action of hexokinase and how it works
- Hexokinase takes an phosphate from ATP and puts it on glucose making glucose 6 phosphate
- GLUT cannot transport phosphorylated glucose so once the glucose is phosphorylated it cannot leave the cell
- If you don’t use up the glucose then you stop phosphorylating it
- Sensitive to feedback inhibition
- It is the investing energy in the system