Module 16 - Metabolism Flashcards
Metabolism Definition
- Chemical change within a cell
- Manufacture energy
- Store energy
- Build new structures
Anabolism
- Creation of large molecules from small
- Using ATP
Catabolism
- Breakdown of large molecules into small
- Release of ATP
Triglyceride Composition
- 3 fatty acid chains
- 1 glycerol molecule
Protein Composition
- Long amino acid chains
Carbohydrate Composition
- Long chains of monosaccharides
Glycolysis
- Series of reactions in cytoplasm
- No oxygen required (anaerobic)
- Produce 2 ATP from 1 glucose
Citric Acid Cycle
- Reactions in mitochondria
- Requires oxygen (aerobic)
- Produce 2 ATP from 1 glucose
Oxidative Phosphorylation (ETC)
- Linked to citric acid cycle
- Reactions in mitochondria
- Produce 34 ATP from 1 glucose
- Requires oxygen (aerobic)
Glucose (ATP)
- Stored as glycogen
- Enter glycolysis
Amino Acids (ATP)
- Converted to pyruvate to enter glycolysis
- Convert to acetyl coenzyme A to enter citric acid cycle
Fat (ATP)
- Broken down into glycerol & free fatty acids
- Glycerol enters glycolysis
- Convert to acetyl coenzyme A to enter citric acid cycle
Glucose Storage
- Majority in skeletal muscle
- Liver for brain use
Glucose as Fuel
- Common for cells
- Only source for brain
Glucose to Glycolysis
- Glucose enters cell
- Converts to glucose-6-phosphate (G6P)
- Enters glycolysis/convert to glycogen
G-6-P Products
- ATP
- Pyruvate
Pyruvate Reactions
- Enter citric acid cycle (O2 present)
- Small ATP & lactate (lack of O2)
Lactic Acid Accumulation
- Blood vessels dilate
- Decrease pH
- Hemoglobin unload more O2
- Increased blood flow & O2 delivery
Citric Acid Cycle Insufficient Oxygen
- Strenuous exercise
- Can’t work at full capacity
- Pyruvate accumulation
- Slowing glycolysis
- Pyruvate converted to lactic acid to continue glycolysis
Reversible Reactions (Lactic Acid)
- O2 restore, lactic acid converts back to pyruvate
- Enters citric acid cycle
- Pyruvate turned back into glycogen as well
Fed State (Absorptive)
- After a meal
- High nutrients
- Store new fuel for later use
Fasted State (Post-Absorptive)
- Between meals
- Low nutrients
- Maintain blood-glucose levels
- Using stored nutrients
Glucose during Fed State
- Stored in muscle & liver
- As glycogen
Excess Glucose & Amino Acids (Fed State)
- Converted to fatty acids by liver
- Released into circulation
- Taken up by fat tissue
- Stored as triglycerides
Amino Acids during Fed State
- Taken up by cells
- Protein synthesis
- Building of muscle proteins/make new carriers
Liver during Fasted State
- Produce & release glucose from storage
- Make new glucose (gluconeogenesis)
Muscle Cells during Fasted State
- No glucose production
- Produce pyruvate or lactate
- Release into blood
Regulation of Metabolism
- Insulin & glucagon
- Secreted by pancreas (islet cells)
Insulin Purpose
- Fed state
- Response to high glucose levels
- Secreted by pancreatic beta cells
Insulin Effects
- Storage of nutrients
- Inhibiting release of nutrients in storage
Insulin Influences
- Increase glucose uptake & use by cells
- Increased glycogen formation
- Increased triglyceride formation
- Increased protein synthesis
Normal Insulin Regulation
- After meal glucose levels increase
- Release of insulin from pancreas
- Storage of nutrients
Diabetes Mellitus
- Beta cells destroyed, no insulin production
- Cells unable to take up nutrients
- Glucose levels rise
- Glucose excreted in urine
Glucagon
- Fasted state
- Response to low glucose levels
- Secreted by pancreatic alpha cells
Glucagon Effects
- Release of stored nutrients
- Targets liver & fat tissue
Glucagon Release Influences
- Increased glycogenolysis
- Increased gluconeogenesis
- Increased lipolysis
Thyroid Hormones (T3 & T4)
- Increase breakdown & release of energy stores
- Regulate BMR
Epinephrine
- Activated by SYNS
- Increased glucagon secretion
- Decreased insulin secretion
- Release of stored fuel
Cortisol
- Release of fuel stores during stress