Glucose regulation and formation Q5 Flashcards
What cells are released by the pancreas and what are their function?
Islet cells, release insulin, glucagon, and numerous hormones.
What cells are released from the liver and what are their function?
Hepatocyte, maintain metabolic homeostasis by normalizing blood glucose, storing glycogen as well as synthesis and degrading various substrates.
What are the two steps of glycolysis that can be aerobic or anaerobic?
Glycolysis and citric acid cycle.
Where are the primary sources of glycogen found?
Liver most and some muscle.
What is the starter for glycogen formation?
Glycogenin
What are the bonds for glycogen?
Long chains of alpha 1-4 and branching with alpha 1-6.
What is the purpose of phosphorylating glucose?
Keeps glucose from leaving the cell and allows for future energy for enzymatic activity.
Starting from glucose, outline the steps and enzymes to form glycogen. What is the regulation point?
How many glucose residues are in each glycogen chain?
12-14.
What are the two fates when glucose-6-phosphate has been created from glycogen?
One is to enter glycolysis or to be exported to the ER of the liver.
Where is glucose-6-phosphates and what is its purpose?
It is only found in the liver and it serves to create glucose where blood sugar is low.
What is the point of regulation when converting glycogen into glucose.
First step when creating glucose 1-phosphate by the glycogen phosphorylase.
What is responsible for regulating glycogen synthase?
Glycogen synthase kinase 3. It will add phosphates to glycogen synthase leaving it deactivated. When the are replaced by OH, it will activate it.
What is the key enzyme responsible for glycogenolysis and how is it regulated?
Glycogen phosphorylase. Phosphorylase b is the inactive form and the non phosphorylated form. When it is in the active form (a) it removes glucose 1-phosphate from glycogen allowing for formation of glucose.
How does insulin activate glycogenesis?
Insulin is released in response to high blood sugar activating GLUTs, hexokinase, glycogen synthase. Glycogen synthase then adds glucose to glycogen chains.
What are the two hormones that activate glycogenolysis? What cells do they work on and what is the end product?
Epinephrine for myocyte and glucagon for hepatocyte.
For liver Epinephrine and glucagon produce glucose 6-phosphate which will yeild blood glucose
In musculater epinephrine will induce glycogenolysis and increase rate of glycolysis.
Where is the primary site for gluconeogenesis?
The liver. Note that glucose 6-phosphatase is in the ER of the liver.
What are the two substrates converted to glucose?
Lactate or pyruvate.
What are the input costs for 1 glucose molecule to be made?
4 ATP, 2 GTP, and 2 NADH + H+
What is the point of regulation for gluconeogenesis?
Converting fructose 1,6-bisphosphatse into fructose 6-phosphate by fructose 1,6-bisphosphatase-1.
What is the cori cycle?
It is the process of converting the lactate produced in the muscles into glucose again in the liver.
What is the major enzyme in responding to cellular energetics? What is it activated by?
AMP kinase by detecting intracellular AMP. It is activated in the large changes in AMP.
What happens to the pancreas, liver, adipose, and muscle in a state of feeding?
Pncrease releases insulin, liver produces glycogen and fatty acids, adipose produces and stores lipids, msucles undergo glycolysis and glycogen production.
What happens to the pancreas, liver, adipose, and muscle in a state of fasting?
Pancreas releases glucagon, liver undergoes gluconeogenesis, glycogenolysis, ketone and glucose release, adipose undergoes fatty acid and glycerol release, muscle undergoes ketone metabolism, and reduced glycolysis.
