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40 terms

Metabolism - Lecture 30 and 31

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Catabolic
--- reactions break down complex organic compounds, providing energy
anabolic
--- reactions synthesize complex molecules from small molecules, requiring energy
ATP
Exchange of energy requires use of --- molecules
oxidation
a decrease in the energy content of a molecule: electrons are lost, plus H+
Reduction
the increase in the energy content of a molecule: electrons gained, plus H+
Electron Transport Chain
-Series of integral membrane proteins in the inner mitochondrial membrane capable of oxidation/reduction
-Each electron carrier can accept and donate electrons
-Small amounts of energy released in small steps. This energy used to form ATP by chemiosmosis
oxygen
Electron Transport Chain:
--- is the final electron acceptor - requried step for this process to occur
ATP
Electron Transport Chain:
--- is transported out of matrix to be used by the cell
Chemiosmosis
---Summary
-Small amounts of energy released as electrons are passed along inner membrane
-This energy is used to pump H+ ions from matrix across inner mitochondrial membrane against their gradient
-ATP synthesis occurs as H+ diffuses through a special H+ channel in inner membrane
Cellular Respiration
Summary of ---:
In the presence of O2, Glucose is broken down into CO2 + H2O + energy used to form ATP
-ATP is transported out of the mitochondria to be used by the cell
Glycolysis
Glucose Metabolism:
Break down of glucose - glucoseto pyruvate/lactate
Glycogenolysis
Glucose Metabolism: Break down of glycogen- glycogen to glucose
glycogenesis
Glucose Metabolism: formation of glycogen - glucose to glycogen
gluconeogenesis
Glucose Metabolism: (formation of new glucose) - other substrates to glucose
lipids
Transport of --- by Lipoproteins
-Most Lipids are nonpolar and must be combined with protein to be transported in blood
-Lipoproteins are spheres containing hundreds of molecules
-Lipoproteins are categorized by function and density
-4 Major classes of lipoproteins
Chylomicrons
Classes of Lipoproteins: (2% protein, 85% TG)
-Form in intestinal epithelial cells to transport dietary fats to adipose cells
VLDLs
Classes of Lipoproteins: (10% protein, 50% TG)
-Fom in hepatocytes to transport triglycerides to adipose cells
LDLs
Classes of Lipoproteins: (25% protein, 50% Chol.) - bad cholesterol
-Carry blood cholesterol to body cells
HDLs
Classes of Lipoproteins: (40% protein, 20% Chol.) -good cholesterol
-carry cholesterol from cells to liver for elimination
oxidized
Fate of Lipids:
--- to produce ATP
liver
Fate of Lipids:
Excess stored in adipose tissue or ---
phospholipids
Fate of Lipids: Synthesize structural or other important molecules
--- of plasma membranes
lipoproteins
Fate of Lipids: Synthesize structural or other important molecules
--- that transport cholesterol
thromboplastin
Fate of Lipids: Synthesize structural or other important molecules
--- for blood clotting
myelin sheaths
Fate of Lipids: Synthesize structural or other important molecules
--- to speed up nerve conduction
cholesterol
Fate of Lipids: Synthesize structural or other important molecules
--- used to synthesize bile salts and steroid hormones
Lipolysis
---: Triglycerides are broken down into glycerol and fatty acids within liver or adipose cells in the presence of epinephrine, norepinephrine, cortisol
beta oxidation
Fatty acids undergo --- in mitochondria to produce Acetyl CoA and lots of ATP
Ketogenesis
--- occurs in liver cells; ketone bodies are used by heart muscle & kidney cortex for ATP production
Lipogenesis
---: triglycerides are synthesized from amino acids or glucose within liver or adipose cells in the presence of insulin
liver
Fate of Proteins:
Proteins are broken down into amino acids, which are transported to the ---
deaminated
Amino acids may be: --- to enter Krebs Cycle
transamination
Amino acids may be: donate amino group to form new amino acids (---)
proteins
Amino acids may be: used to synthesize new --- throughout the body
no storage
Fate of Proteins: excess amino acids may be converted into glucose or triglycerides (---)
Absorption
Fate of Proteins:
--- of AA into body cells is stimulated by insulin-like growth factors (IGFs) and insulin
absorptive state
Metabolism during ---:
-Represents the time after a meal when nutrients enter the blood and need to be stored
-Hepatic portal system for glucose and amino acids - go to liver first
-Lacteals for dietary fats
Absorptive State
--- Summary;
-Storage of excess fuels occurs in hepatocytes, adipocyes, skeletal muscle
-Most glucose entering liver cells is converted to glycogen (10%) or triglycerides (40%)
-Dietary lipids are stored in adipose tissue
-Amino acids are deaminated to enter Krebs cycle or are converted to glucose or fatty acids
-Amino Acids not taken up by hepatocytes are used by other cells for synthesis of proteins
Postabsorptive State
Metabolism during ---:
-4 hours after a meal when absorption of all nutrients is complete (similar to starvation)
-Maintaining normal blood glucose level (70-110 mg/dl of blood) is major challenge --> goal is to put glucose back into the blood or use alternative fuel sources
Postabsorptive State
--- Summary:
Glucose enters blood from the liver
-glycogenolysis
-gluconeogenesis
-glycerol from adipose tissue
-amino acids and lactic acid from muscle
-Alternative fuel sources are:
-Fatty acids from adipose fed into Krebs as Acetyl CoA for most cells
-oxidation of ketone bodies by heart and kidney