Flashcards in Lecture 7 Cellular Metabolism part 2 Deck (15)
How is it stimulated?
formation of glycogen from glucose (glucose -> glycogen)
the hormone insulin stimulates glycogen synthesis when blood [glucose] is high
Where is glycogen stored?
mostly in the liver
some in skeletal muscle
role in homeostasis of glucose?
How is it stimulated?
What happens in skeletal muscle?
glycogen -> glucose
In the liver glycogen in converted to glucose and released into the blood to maintain glucose homeostasis
(helps between meals)
The hormones glucagon stimulates glycogenolysis in the liver when blood glucose is low .
In skeletal muscle glycogen -> glucose, metabolized in active muscle cells
Tissue Utilization of proteins
Protein Catabolism: hydrolysis of polypeptides to amino acids
Deamination- removal of the amino group
- Keto acids enter the Citric Acid Cycle and release Co2+H2O+energy
NH3 is converted into urea and excreted by the kidneys
Example of Keto Acids
oxaloacetate and pyruvate
excess creates issues
Transamination in proteolysis
-NH2 group is transferred to another amino acid
Tissue Utilization of Proteins
Normal protein turnover in cells
protein metabolism increases during starvation, injury, heavy exercise, high protein diet
What does excess fat catabolism produce?
why may this happen?
produces ketone bodies which are acidic
this happens with low carb diet that has an increase in eating fats and proteins
Lipolysis (fat metabolism)
what is it?
Lipolysis is catabolism of fats and other lipids
a. Hydrolysis of triglycerides; broken into fatty acids and glycerol
b. Beta oxidation- stepwise oxidation of fatty acids
- fatty acids are broken into 2C units -> acetyl CoA -> Krebs cycle -> CO2 +H2O
- high energy yield >100 ATP per fatty acid
2X more energy yield per gram than carbohydrates
fatty acids are synthesized from 2C units of acetyl CoA
fatty acids are combined with glycerol to form triglycerides and phospholipids
tissue utilization of fatty acids
-what uses fatty acids?
-broken down by?
triglycerides are stored mostly in adipose tissue
lipids are transported in the blood by lipoproteins (HDL & LDL)
liver, heart, and resting skeletal muscle use mostly fatty acids for energy
fatty acids are broken down only by aerobic metabolism
excess fat catabolism -> formation of ketone bodies (metabolic acidosis)
making new glucose
formation of glucose from non-carbohydrate sources: amino acids, glycerol, lactate
-occurs mostly in the liver
-important when glycogen stores are depleted or during fasting
-stimulated by hormones cortisol and glucagon
-keeps glucose supply to brain going