Flashcards in Energy Balance And Metabolism Deck (45)
What uses ATP?
-active ion transport
-synthesis of molecules
-cell division and growth
What is the definition of delta G?
-difference in free energy when 1 mole of each reactant is converted to 1 mole of each product at 1 atm pressure at 25 degrees Celsius
What is the amount of energy released by ATP? Under normal conditions in the body?
What are the two ways that glucose is transported into tissue cells?
-via active sodium-glucose cotransport
+active transport of sodium provides energy for absorbing glucose against a concentration gradient
-via facilitated transport
+only transported from higher to lower concentrations
What can affect glucose transport?
-presence of insulin increases glucose transport 10x
-phosphorylation of glucose prevents diffusion out of cell
-phosphorylation can be revered in liver, renal, and intestinal cells
What are factors that active phosphorylase?
-epinephrine (from adrenal medulla)
-glucagon(from alpha cells of pancreas)
What are some effects of phosphorylase?
-promotes conversion of glycogen to glucose
-glucose can then be released into blood
What are the end products of glycolysis?
-2 pyruvic acid
-4 hydrogens -> release is catalyzes by dehydrogenase
What are the end products when pyruvic acid is converted to acetyl CoA?
-2 acetyl CoA
Where does the citric acid cycle take place?
-occurs in mitochondrial matrix
What are the ends products of the citric acid cycle?
What is the net reaction of TCA?
2 acetyl CoA + 6H2O + 2ADP -> 4CO2 + 16H + 2CoA + 2ATP
Where does oxphos occur?
What are the fates if the hydrogen atoms from previous cycles?
-hydrogens are removed in pairs
-one member of each pair becomes H+
-the other member of a pair combines with NAD+ -> NADH
What happens to the electrons removed from the hydrogen ions?
-enter the electron transport chain
What are the major components of the electron transport chain?
-several iron sulfide proteins
-cytochrome A3 (cytochrome oxidase)
+located on inner membrane
+can give up electrons to oxygen
Outline the chemiosmotic mechanism.
-electrons pass through chain, releasing large amounts of energy
-energy is used to pump H+ from inner matrix into outer chamber between innate and outer membranes
-high conc of H+ created in chamber
-strong negative potential created in inner matrix
-H+ flow from high to low conc through ATP synthetase
-energy derived from H+ flow is used by ATPase to convert ADP to ATP
-for each 2 electrons that pass through the electron transport chain, up to 3 ATP molecules are synthesized
2 pairs of hydrogens derived from where enter the electron transport chain at a later point and provide energy for 2 molecules per pair
What are the number of ATPs formed per glucose molecule?
-2 ATPs from glycolysis
-2 ATPs from TCA cycle
-34 ATPs from oxphos
-max number of ATPs/glucose = 38
-456,000cal/mol glucose -> 66% efficiency
How do you get ATP?
-oxidation of proteins, carbs, and fats
What is the PPP?
Cyclical pathway in which one molecule of glucose is metabolized for each revolution of e cycle
-for every 6 glucose that enter, 5 are resynthesized
-mostly used for the synthesis of fats and other substances
-hydrogen sulfide generated from this pathway are bound to NADP+
-participates in the conversion of acetyl CoA into FA chains
What happens with the storage of glucose in the body?
-glucose is preferentially stored as glycogen until the storage cells (liver and muscle) are saturated
-excess glucose is then converted into fat and stored in fat cells
Describe triglyceride absorption from the intestine.
-triglycerides into monoglycerides and FAs
-intestinal epithelial cells resynthesized these into triglycerides that enter the lymph as chylomicrons
-apoprotein B is absorbed to the chylomicrons surface
-transported to the venous system via thoracic duct
What removes chylomicrons from the body?
What does lipoprotein lipase do?
-is transported to surface of capillary epithelial cells
-hydrolyzes chylomicron triglycerides, releasing FAs and glycerol
All normal energy requirements of the body can be provided by the oxidation of _______________ without using ________ or ________ as energy sources.
-carbs or proteins
What are two conditions that increase utilization of fat for energy?
What are the two types of chylomicrons? Aka where are they synthesized?
-synthesized in intestinal cells
-synthesized by the liver
+VLDLs, IDLs, LDLs, HDL
What is in VLDLs?
-high conc of triglycerides and moderate amounts of cholesterol and phospholipids
-transport lipids mainly from liver to adipose tissue