Metabolism Overview Flashcards
Define Catabolism
The breakdown of large molecules, commonly involving oxidative reactions (Exothermic, releases ATP via respiratory chain)
Define Anabolism
Synthesis of large, complex compounds from smaller precursors (Endothermic, requires ATP // Amino acids, protein, carbohydrates, triacylglycerol // glycogen)
Define Amphibolic
Participates in anabolic and catabolic functions (Citric Acid Cycle)
States where normal metabolism allows for adaptation
Fed, Fasting, Starving, Exercising, Pregnancy, Lactating
The ____ is the source of glucose
Intestine
In the fed state, ____ stimulates ____ uptake by cells
Insulin; glucose
Glucose uptake by the liver is _______
Independent of insulin
Insulin is made in the ____ and controls _____ and uptake during the ____
Endocrine pancreas; glucose oxidation ; fed state
Excess glucose is stored in the muscle as
Glycogen
During the fed state brain glucose uptake is unaltered (T or F)
TRUE
During the fed state, lipolysis is….
Suppressed
Increased during the the fed state
Muscle/Adipose Glucose intake and protein synthesis
Decreased during the fed state
Muscle fatty acid uptake, insulin secretion
_____ is the source of glucose and glucose production is taken up by the ____
Liver; brain
Prolonged fasting depleted glycogen reserves and ______ arising from net muscle protein breakdown
Amino acids
______ from hydrolysis of stored muscle glycogen provides carbons to support ______
Lactate; gluconeogenesis
Adipose releases _____ that are used by liver and skeletal muscle
free fatty acids
Ketones are ______
Partially oxidized fatty acids
glucose transporter of muscle + adipose tissue in intracellular vesicles
GLUT-4
Increased in the fasting state
Plasma non-esterified fatty acids, plasma concentration of ketone bodies
Decreased in fasting state
Muscle fatty acid uptake, insulin secretion
Alternative fuel size during prolonged fasting/starvation
Ketones
During starvation, ____ is used to supply amino acids for ______ and oxidized in skeletal muscle
protein; gluconeogenesis
Substrates during starvation are oxidized by the _____ to support energy demands and contribute to _____ synthesis
Liver ; ketone body
Adipose tissue reserves are depleted during ____
prolonged starvation
Main substrates during prolonged starvation
glucose, amino acids, ketone bodies
States of abnormal metabolism
Nutritional deficiency
Caloric excess
Enzyme deficiency or inappropriate regulation
Abnormal secretion of hormones
Actions of drugs and toxins
Macronutrient Metabolic Fuel %
Carbohydrate = 40-60%
Lipid = 30-40%
Protein = 10-15%
Carbohydrate Metabolic Pathways
Glycolysis, Citric Acid Cycle, Glycogenesis, Pentose Phosphate Pathway, Glycogenolysis, Gluconeogenesis
Lipid Metabolic Pathways
Lipolysis, B-Oxidation, Citric Acid Cycle, Lipogenesis, Ketogenesis, Cholesterol & Steroid Synthesis, Esterification
Protein Metabolic Pathways
Nonprotein Derivative Synthesis, Protein/A.A. Synthesis, Transamination & Deamination, Ketogenesis, Citric Acid Cycle, Gluconeogenesis, Urea Synthesis
Two levels of organization of metabolic pathways
Tissue/Organ Level
Subcellular Level
Tissue/Organ Level
Substrates entering or metabolite exiting tissues/organs
Subcellular Level
Each organelle or compartment has specific roles in metabolic pathways
Four metabolic pathways that take place in the liver
Gluconeogenesis, Plasma Protein Synthesis, Lipogenesis, Ketogenesis
Pathways that take place in the Mitochondria
Kreb’s/TCA Cycle, B-Oxidation, Gluconeogenesis (and cytosol)
Pathways that take place in the Cytosol
Pentose Phosphate Pathway, FA Synthesis, Gluconeogenesis (and mitochondria)
Pathways that take place in the Ribsomes
Protein synthesis
Mechanisms involved in regulation of metabolites through metabolic pathways
Nonequilibrium, Allosteric modifiers, Hormones
Nonequilibrium Reaction Catalyst Enzymes
Hexokinase, phosphofructokinase, pyruvate kinase
Allosteric Modifiers
Changes enzyme efficiency by modifiers/effectors (changes enzyme function)
Allosteric Inhibitor Reaction
Glucose –> G6P inhibits hexokinase
Hormones
Can rapidly alter activity or cellular localization of existing enzyme molecules
Or slowly changing enzyme content by altering rate of enzyme synthesis
Strictly ketogenic amino acids
Lysine and Leucine
Then converted to Acetyl CoA ONLY
____ and ____ are the hormones that control glucose oxidation and uptake
Insulin ; glucagon
In the fed state, glucose from the liver goes to
the brain, adipose tissue, muscle
In the fed state, FFAs from adipose tissue goes to
The liver and muscle tissue
In the fasting/starvation state, _____ is made in the endocrine pancreas
Glucagon
The products of digestion when completely oxidized become ____
Acetyl CoA, which is then oxidized by the CAC
