Carbohydrate Metabolism 9-19-16 Flashcards
What are the 4 major organs/cell types that regulate metabolically pathways?
- Pancreas
- Liver
- Muscle
- Adipose Tissue
What are the cells in the Pancreas that help regulate metabolism and what are their function?
-Islet cells
Function: releases insulin, glucagon, and numerous hormones
What are the cells in the liver that regulate metabolism?
-hepatocytes
Function: maintains metabolic homeostasis by normalizing blood glucose, storing glycogen, and synthesizing and degrading glycogen, glucose, fatty acids, proteins and ketone bodies
What cells in muscle help regulate metabolism?
Skeletal, smooth, and cardiac myocytes
Function: utilizes glucose, fatty acids, and amino acids to fuel muscular activity
What cells in Adipose tissue help regulate metabolism?
Adipocyte
Function: Storage
Name the key regulators in metabolism
- Insulin
- Glucagon
- Epinephrine
- Glucose
- ATP/AMP
Name the 4 functions of Glucose as a central metabolic component
- Source of ATP
- Energy Storage
- Molecular precursor
- Structural backbone
What are the 4 major pathways of Carbohydrate Metabolism?
- Respiration –> Forms ATP
- Storage –> Forms glycogen
- Regenerative –> Forms glucose
- Synthetic –> Forms nucleus acids, lipids, amino acids
Which metabolic pathways are exclusive?
- Glycolysis and gluconeogenesis.
- Glycogenesis and glycogenolysis
What are the main catabolic pathways And their products?
- Glycolysis -> ATP, NADH
- Citric Acid Cycle -> ATP, NADH
- Oxidative Phosphorylation -> ATP, CO2
- Glycogenolysis -> Glucose
What are the major anabolic pathways and their products?
- Glycogenesis -> Glycogen
- Gluconeogenesis -> Glucose
What enzymes help digest complex carbs?
- Amylases
- Lactase
- Sucrase
- Maltase
Describe Glycogen and why it is important
- Branched glucose homopolysaccharide
- primary mechanism for intracellular storage
- Necessary to maintain cellular osmolarity
- Forms large molecular complexes
- Stored in granule organelles
- Primarily found in the liver and muscle
- 10% liver weight
- 2% muscle by weight
What are the Steps in Glycogenesis?
Check on the power point
What are the steps of glycogenolysis?
Check on the slide
What are the two key enzymes in glycogen metabolism?
- Glycogen Synthase
- Glycogen Phosphorylase
What protein regulates Glycogen Synthase and how does it do it?
Glycogen Synthase Kinase 3
- It phosphorylates glycogen synthase
- Glycogen synthase is inactivated by phosphorylation
What things activate PP1?
- Insulin
- Glucose 6-Phosphate
- Glucose
What inhibits PP1?
- Glucagon
- Epinephrine
What inhibits GSK3?
Insulin
What are the two Glycogen Phosphorylase Allosteric forms?
- b (Less active) form
2. a (more active) form
Where does Gluconeogenesis happen?
- Primarily in the Liver
- Can occur in all cells
What are the major sources of substrates to form Glucose?
- Lactate is a big one
- Also pyruvate
What is the major protein for signaling in driving metabolic states in different organs?
AMP Kinase (AMPK)
