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Flashcards in Energy Balance And Metabolism Deck (45)
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What uses ATP?

-active ion transport

-muscle contraction

-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?

- -7300cal/mol

- -12,000cal/mol


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

-2 ATP


What are the end products when pyruvic acid is converted to acetyl CoA?

-2 acetyl CoA

-4 hydrogens

-2 CO2


Where does the citric acid cycle take place?

-occurs in mitochondrial matrix


What are the ends products of the citric acid cycle?

-16 hydrogens

-2 ATP

-4 CO2


What is the net reaction of TCA?

2 acetyl CoA + 6H2O + 2ADP -> 4CO2 + 16H + 2CoA + 2ATP


Where does oxphos occur?

-mitochondrial cristae


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

-ubiquinone (Q)

-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

TCA cycle


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?

-adipose tissue

-skeletal muscle



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?


-diabetes mellitus


What are the two types of chylomicrons? Aka where are they synthesized?

-synthesized in intestinal cells

-synthesized by the liver


What is in VLDLs?

-high conc of triglycerides and moderate amounts of cholesterol and phospholipids

-transport lipids mainly from liver to adipose tissue


What is in LDLs?

High conc of cholesterol and moderate conc of phospholipids