Pathways linking Glycogen, Glucose & Pyruvate
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Glycogen to glucose
Glycogenolysis
Glucose to glycogen
Glycogenesis
Pyruvate to glucose
Gluconeogenesis
Glucose to pyruvate
Glycolysis
When does glycogenesis take place?
When blood glucose levels are sufficiently high to allow excess glucose to be stored in liver + muscle cells.
What is glycogenesis inhibited by?
Presence of G-6-P
What is glycogenesis stimulated by?
Insulin
What does insulin do for glycogenesis?
Facilitates the uptake of glucose into muscle cells but not req for liver cells. But, in liver cells insulin does stimulate glycogenesis.
Why does the overall pathway of glycogenesis consume energy?
Due to 1 ATP + 1 UTP being consumed for each mol of glucose used.
Where is hexokinase found and where is glucokinase found?
Hexokinase = Muscle, brain + adipose tissue Glucokinase = Liver + pancreas
Relationship of G-6-P with hexokinase + glucokinase
Hexokinase = Allosterically inhibited by G-6-P Glucokinase = NOT inhibited by G-6-P
Which is induced by insulin in NORMAL individuals? - glucokinase or hexokinase?
Glucokinase
Glycogenesis Overview of the change in glucose showing only the substrates
Glucose G-6-P G-1-P Uracil-diphosphate glucose (UDP) Glycogen
GLYCOGENESIS Enzyme for Glucose –> G-6-P
Glucokinase or hexokinase
GLYCOGENESIS Enzyme for G-6-P to G-1-P
Phosphoglucomutase
GLYCOGENESIS Enzyme for G-1-P to Uracil-diphosphate glucose (UDP)
UDP-glucose pyrophosphorylase
GLYCOGENESIS Enzyme for UDP glucose to Glycogen
Glycogenin Glycogen synthase +/or glycogen branching enzyme
What does UDP-glucose consist of?
2 P groups + uracil (nucleic acid)
What -ively regulates glycogenesis by disrupting the proteins needed for the process?
Epinephrine/Adrenaline
What does epinephrine do to glycogenesis?
Stops it + starts glycogenolysis to convert glucose into energy, Cells need much ATP to overcome the threat.
Where is potential energy found in glycogens?
W/in the glucose residues that make up its structure. In response to the bodys demands, these reduces can be cleaves from the non-reducing ends of the glycogen branches + put through energy releasing pathways.
Where does glycogenolysis take place?
Muscle + liver cells
When does glycogenolysis take place?
When more energy is needed. When ATP levels are low
How many units of glucose can 1 mol of glycogen contain?
30,000 units of glucose linked together with its centre structure as the protein glycogenin.