Glucose as a metabolic fuel -P notes biochemistry - Flashcards
Glucose is stored as …. in the … and ….
glycogen
liver
skeletal muscle
Which type of cell has no mitochondria? Significance in the context of glucose
Red Blood Cells (RBCs) = no mitochondria
Therefore all energy = through glycolysis
Which part of the kidney has high energy requirement and why?
Renal medulla
- has high energy requirement
- due to active transport in reabsorption
Availability of glucose = …. …. mM glucose in blood plasma
4-6
Use of glucose = ,,,,g/day
160g/day = use of glucose
Brain - use of glucose
- Brain = 120g/day (75%)
- brain obtains energy through metabolism of ketone bodies in starvation
Skeletal muscles
muscle glycogen can be used …
muscle glycogen is only used by muscles
SKM = can also use blood glucose from the Cori cycle
Type II fibres = few mitochondria
Glucose Transporters - How many different types are there for the purposes of the medicine course
4
GLUT 1
GLUT 2
GLUT 3
GLUT 4
Recall the mnemonic to remember the number and location of th GLUT transporter
B1 2Kil B3 today Fml
Glut 1 - RBC, blood brain barrier, placenta
Glut 2 - liver, kidney, intestine
Glut 3 - Brain, testes (sperm)
Gut 4 - Heart, muscle, fat
unrefined version - read following flashcards to understand the MSTC terms
Transport across all cell membranes occurs by …..
GLUT 1-4
GLUT 1 =……
RBCs + BBB
. Equilibrates intra/extracellular glucose
Glut 2-
….
Liver, pancreas and kidneys
Bidirectionaltransporter
High Kmvalue (high [substrate] gives half Vmax) - allowsglucose to equilibrate either side of the membrane
allows glycolysis/gluconeogenesis as [intracellular] = [extracellular], if low then the liver does not take up glucose and glycolysis decreases
When [glucose] is high, β cells in pancreas release insulin promoting glycolysis
GLUT 3….
neurons + placenta
Low Km, therefore constant uptake of glucose independent of conc (low [glucose] gives half Vmax)
GLUT 4 -
GLUT4 - Adipose tissues + SKM/CM
Regulated byinsulin
