Term
| What characterizes an amphipathic molecule? |
|
Definition
| both hydrophobic and hydrophilic characteristics |
|
|
Term
| What causes portal hypertension in the cirrhotic liver and what is the result? |
|
Definition
| Decreased perfusion; esophageal varicies |
|
|
Term
| How many Kcal/gram of alcohol? |
|
Definition
|
|
Term
| What vitamins does alcohol consumption limit the absorption of? |
|
Definition
Thiamine, B12, and folic acid
(among others) |
|
|
Term
| What is the function of Alcohol Dehydrogenase (ADH)? |
|
Definition
To convert ethanol to Acetaldehyde
GAIN ONE NADH |
|
|
Term
| What is the function of Aldehyde Dehydrogenase (ALDH)? |
|
Definition
To convert acetaldehyde to Acetate
GAIN ONE NADH |
|
|
Term
| What is the function of Acetyl CoA Synthetase (ACS)? |
|
Definition
| Convert acetate to Acetyl CoA |
|
|
Term
| Where does the action of ADH take place? |
|
Definition
|
|
Term
| Where does the action of ALDH take place? |
|
Definition
|
|
Term
| What are the effects of the excess NADH produced in ethanol metabolism? |
|
Definition
Increased lactate and ketone bodies;
decreased fatty acid oxidation and gluconeogenesis |
|
|
Term
| What is another role of ALDH? |
|
Definition
| To release the NO from nitroglycerin (relieve the pain of angina) |
|
|
Term
| What happens to Acetyl CoA that results from ethanol metabolism? |
|
Definition
| It is mostly oxidized via the citric acid cycle |
|
|
Term
|
Definition
An alternative pathway for alcohol metabolism that usually only activates at high or constant ethanol levels; DOES NOT GENERATE NADH, but does generate reactive oxygen species
CONVERTS ETHANOL TO ACETALDEHYDE |
|
|
Term
| What is the important function part of the MEOS system? |
|
Definition
Cytochrome P450 enzyme called CYP2E1
This uses NADPH and molecular oxygen to oxidize ethanol |
|
|
Term
| What else is metabolized by the CYP2E1? |
|
Definition
|
|
Term
| In chronic alcoholism, what is the sole mediator of increased alcohol metabolism? |
|
Definition
|
|
Term
| What is the main consequence of inducing the MEOS system? |
|
Definition
| Increased amounts of Toxic ACETALDEHYDE |
|
|
Term
| What effect does alcoholism have on the metabolism of drugs that use the MEOS system for breakdown? |
|
Definition
Higher dose of drugs for effectiveness
BUT
If ethanol is consumed while taking the drug, alcohol competes for the enzyme and a lower dose of the drug may be effective |
|
|
Term
| What effect does chronic alcoholism have on levels of MEOS? |
|
Definition
|
|
Term
| How many ATP are generated by the conversion of ethanol to acetaldehyde by ADH? |
|
Definition
| as many as 15 (because of Citric Acid Cycle) |
|
|
Term
| What are the 3 chemical structures responsible for the toxic effects of ethanol metabolism? |
|
Definition
1) Increased NADH: NAD+ ratio
2) Acetaldehyde (toxic)
3) Increased free radical production |
|
|
Term
| What are the acute metabolic effects of alcohol on the liver? |
|
Definition
| Excess TGs, hyperlipidemia, fatty liver, increased ketone bodies because TCA cycle is inhibited, ketosis |
|
|
Term
| What are the effects of alcohol on blood sugar? |
|
Definition
Fasting hypoglycemia
Hyperglycemia following a meal |
|
|
Term
| Why does alcohol metabolism cause an increase in TGs? |
|
Definition
| High NADH inhibits beta oxidation of fatty acids, so there are too many in the liver and they get converted to TGs |
|
|
Term
| Why does alcohol metabolism cause ketosis? |
|
Definition
| High NADH causes OAA to reduce to malate so that citrate cannot be made- as a result, Acetyl CoA cannot enter the TCA cycle, and excess AcetylCoA makes KETONE BODIES |
|
|
Term
| What are two effects of high levels of NADH from alcohol metabolism on blod sugar? |
|
Definition
Inhibits gluconeogenesis (hypoglycemia during fasting)
Inhibits glycolysis
(hyperglycemia in fed state) |
|
|
Term
| What why does alcohol metabolism cause hyperuricemia? |
|
Definition
| Excess lactated inhibits uric acid excretion: patients with gout should avoid alcohol |
|
|
Term
| Why does alcohol metabolism cause fatty liver disease? |
|
Definition
| Ethanol oxidation replaces fat as a fuel so it accumulates in the liver |
|
|
Term
| Why does acetaldehyde cause free radical damage? |
|
Definition
First, more free radicals are formed by acetaldehyde-adducts
Second, acetaldehyde binds glutathione and lowers its ability to protect against ROS |
|
|
Term
| What leads to decreased serum protein production in alcohol-induced hepatitis? |
|
Definition
| Tubulin modification by acetaldehyde- decreased albumin, transferrin, and clotting factors |
|
|
Term
| What is hepato-encephalopathy? |
|
Definition
Liver cannot detoxify so that toxins affect the brain
Alcohol also decreases absorption of vitamins (thiamine) affecting glucose metabolism in the brain and heart |
|
|
Term
| What is Wernicke-Korsakoff Syndrome? |
|
Definition
| Altered mental status- the result of alcohol-induced decreased glucose metabolism in the brain (vitamin deficiency) |
|
|
Term
| What causes fibrosis in alcohol-induced liver disease and what initiates it? |
|
Definition
Stimulation of mitogenic development of stellate cells into myofibroblasts;
Macrophages are activated by acetaldehyde-adducts and ROS |
|
|
Term
| What effect does excessive alcohol consumption have on Citric Acid Cycle activity? |
|
Definition
|
|
Term
| What causes impaired judgment and psychoses in a chronic alcoholic? |
|
Definition
|
|
Term
| What is deficient if laboratory studies show a decrease in transketolase activity of RBCs? |
|
Definition
|
|
Term
|
Definition
Congestive heart failure due to thiamine deficiency- HIGH OUTPUT heart failure- wet= fluid retention
ADMINISTER THIAMINE |
|
|
Term
| What hormone stimulates fatty acid synthesis in the liver? |
|
Definition
|
|
Term
| What hormone stimulates gluconeogenesis in the liver? |
|
Definition
|
|
Term
| What bond, found in cellulose, cannot be broken down by us humans? |
|
Definition
|
|
Term
| What bond is broken by amylase? |
|
Definition
| Alpha 1,4 glycosidic bonds |
|
|
Term
| Where are sucrase and maltase found? |
|
Definition
| On the surface of the intestinal lumen |
|
|
Term
| What sugars are absorbed without digestion? |
|
Definition
| Fructose, ribose, and glycerol |
|
|
Term
| What are the products of starch digestion by amylase in the mouth? |
|
Definition
| Maltose and limit dextrins |
|
|
Term
|
Definition
| A shorter polysaccharide chain made by the breakdown of a larger molecule (STARCH) |
|
|
Term
| What are the two monosachharides of table sugar (sucrose)? |
|
Definition
|
|
Term
| In lactose intolerance, lactose cannot be broken down into what two sugars? |
|
Definition
|
|
Term
| Besides salivary amylase, where does the other amylase get secreted? |
|
Definition
| Pancreas- pancreatic amylase |
|
|
Term
| What type of bonds hold together the monosaccharides of amylose (starches)? |
|
Definition
| Glucose Alpha 1-4 Glucose- This bond is broken by amylase |
|
|
Term
| What bond holds together the monosaccharides of sucrose? |
|
Definition
| Glucose Alpha 1- Beta 2 Fructose |
|
|
Term
| What bond holds together the monosaccharides of lactose? |
|
Definition
| Galactose Beta 1-4 Glucose |
|
|
Term
| What is the action of the glucoamylase complex in the small intestine? |
|
Definition
Cleavage of Alpha1-4 linkages
DEGRADES MALTOSE AND MALTOTRIOSE |
|
|
Term
| What is the action of the Sucrase-Isomaltase Complex? |
|
Definition
| Digestion of SUCROSE and maltose |
|
|
Term
| What is the function of trehalase, and where can you find the sugar that it acts on? |
|
Definition
Cleaves Trehalose Glucose Alph1,1 Glucose
Mushrooms, honey, and shrimp |
|
|
Term
| What class of enzyme is lactase and what bond does it break? |
|
Definition
| Beta Glycosidase; Galactose Beta1,4 Glucose bonds |
|
|
Term
| What ethnic minority has a genetic Trehalase deficiency? |
|
Definition
|
|
Term
| What did the Dalai Lama say to the hot dog vendor? |
|
Definition
| "Make me one with everything" |
|
|
Term
| What causes lactose intolerance? |
|
Definition
| Lactase deficiency from injury to intestinal mucosal cells; gastroenteritis; excess alcohol consumption |
|
|
Term
| What happens to lactose in the absence of lactase? |
|
Definition
| Bacterial fermentation= bloating, flatulence, diarrhea, H2 on the breath |
|
|
Term
| What two tissues increase GLUT4 expression on the cell surface in response to insulin? |
|
Definition
|
|
Term
| Where do we find GLUT1 receptors? |
|
Definition
| RBCs and most other cells |
|
|
Term
| What glucose transporter is insulin sensitive? |
|
Definition
|
|
Term
| Where do we find GLUT2 receptors? |
|
Definition
| Intestine, Beta cells of the liver |
|
|
Term
| Where do we find GLUT3 receptors? |
|
Definition
|
|
Term
| Where do we find GLUT4 receptors? |
|
Definition
|
|
Term
| Where do we find GLUT5 receptors? |
|
Definition
|
|
Term
| What type of receptor is the insulin receptor? |
|
Definition
|
|
Term
| What enzyme is deficient in Von Gierkes disease and what is the effect of this deficiency? |
|
Definition
| Glucose 6- Phosphatase; glycogen stays trapped so: hypoglycemia, enlarged liver and kidney, acidosis, lipemia |
|
|
Term
| What enzyme is deficient in Andersen disease and what is the effect of this deficiency? |
|
Definition
| Branching Enzyme; cannot build large, densely branched glycogen so: glycogen looks like a foreign body and the liver reacts- hepatosplenomegaly- Usually Fatal |
|
|
Term
| What enzyme is deficient in McArdles disease and what is the effect of this deficiency? |
|
Definition
| Glycogen Phosphorylase in muscle; exercise induced muscular pain, cramps, weakness |
|
|
Term
| What enzyme is deficient in Hers disease and what is the effect of this deficiency? |
|
Definition
| Liver Glycogen Phosphatase; Hepatomegaly and hypoglycemia |
|
|
Term
| What enzyme is deficient in Coris disease and what is the effect of this deficiency? |
|
Definition
| Debranching enzyme; inability to pick apart glycogen so: milder hypoglycemia, hepatomegaly |
|
|
Term
| What enzyme sequesters glucose in the cell? (1. most tissues; 2. liver) |
|
Definition
1) Hexokinase- non-insulin dependent
2) Glucokinase- Insulin activated |
|
|
Term
| What enzyme converts glucose-6-phosphate back to glucose? |
|
Definition
|
|
Term
| What type of bond is made by Branching Enzyme? |
|
Definition
| Alpha 1,6 glucosidic branching from earlier parts of the glycogen backbone |
|
|
Term
| What is the primer for glycogen synthesis? |
|
Definition
|
|
Term
| What is the action of Uridyl Transferase (UDP-glucose Pyrophosphorylase)? |
|
Definition
| To convert Glucose 1 Phosphate to UDP-Glucose (Releases 2 phosphates) |
|
|
Term
| What is the action of Phosphoglucomutase? |
|
Definition
| To convert G-6-P to G-1-P |
|
|
Term
| What is the action of glycogen synthase? |
|
Definition
| To elongate glycogen by one sugar |
|
|
Term
| What disease is marked by a deficiency in branching enzyme? |
|
Definition
| Andersens' Disease- causes very long unbranched glucose chains that precipitate in the Liver causing HEPATOMEGALY |
|
|
Term
| What enzyme breaks down glycogen, and what activates it? |
|
Definition
Glycogen Phosphorylase;
Glucagon- PKA
Epinephrine- via PKA, PKC, Ca++ |
|
|
Term
| What is the product of glycogen breakdown? |
|
Definition
|
|
Term
| What disease is marked by a deficiency of debranching enzyme? |
|
Definition
| Cori's Disease- Severe hypoglycemia and enlarged liver |
|
|
Term
| A defect in what liver enzyme causes the most severe hypoglycemia, and what is the name of the disease? |
|
Definition
| Glucose-6-Phosphatase- Von Gierke's Disease |
|
|
Term
| GLUT4 expression is turned on by activation of which PK complex? |
|
Definition
|
|
Term
| What is considered a normal blood glucose level? |
|
Definition
|
|
Term
| What effect does insulin have on blood glucose? |
|
Definition
| Insulin lowers blood glucose |
|
|
Term
| What second messenger is activated after insulin binds to its receptor, and which protein kinase does it activate? |
|
Definition
|
|
Term
| What second messenger is activated after glucagon binds to its receptor, and which protein kinase does it activate? |
|
Definition
|
|
Term
| What is the main driving condition for the breakdown of fat and protein? |
|
Definition
|
|
Term
| Where in the pancreas is glucagon produced, and why is it secreted? |
|
Definition
| Alpha Cells in response to low glucose |
|
|
Term
| Where in the pancreas is insulin produced, and why is it secreted? |
|
Definition
| Beta Cells in response to high glucose |
|
|
Term
| What effect does epinephrine have on Triglycerides? |
|
Definition
| Epinephrine causes breakdown |
|
|
Term
| What is the major consequence of excess glucose acting on proteins? |
|
Definition
| Non-enzymatic glycosolation (as in HbA1C) |
|
|
Term
| How does type I diabetes cause a hyper-osmotic coma? |
|
Definition
| Pulling water from the cells, especially brain cells |
|
|
Term
| Where is pre-pro-insulin synthesized and cleaved? |
|
Definition
|
|
Term
| Where is pro-insulin sorted and packaged, and what ion is it packaged with? |
|
Definition
| Golgi apparatus, packaged in storage vesicles with Zn |
|
|
Term
| What is cleaved from pro-insulin to activate it, and what is the usefulness of the cleaved part? |
|
Definition
C- peptide (or C-protein)
Can be used as a measure of how much insulin is available, secreted, since it hangs around in spite of the liver using insulin very quickly |
|
|
Term
| What is the effect of ATP on K channels in the pancreatic Islet cells? |
|
Definition
| ATP inhibits K+ channels causing DEPOLARIZATION and vesicle release |
|
|
Term
| What is the action of sulfonylurea drugs? |
|
Definition
| They trigger INSULIN RELEASE by inhibiting K-ATP channels of Beta cells- basically, they do the same thing as ATP- Ca channels open, the membrane depolarizes, and insulin granules are released |
|
|
Term
| What is the cause of Type I DM? |
|
Definition
| Autoimmune destruction of Beta cells |
|
|
Term
| What is the cause of Type II DM? |
|
Definition
| Insulin resistance in skeletal muscle and liver |
|
|
Term
|
Definition
Maturity Onset Diabetes of the Young
-DECREASED GLUCOKINASE ACTIVITY which sequesters glucose in the cell
-this means you need MORE GLUCOSE TO GET A REGULAR AMOUNT OF ATP
-INSULIN IS ONLY RELEASED AT HIGH GLUCOSE LEVELS |
|
|
Term
| What two main factors suppress the synthesis of Glucagon? |
|
Definition
|
|
Term
| What effect does cortisol have on glucagon release? |
|
Definition
|
|
Term
| What effect do high concentrations of amino acids have on glucagon release? |
|
Definition
| High concentrations of amino acids (as after a high protein meal) INCREASE glucagon release even if insulin is also high- this increases the conversion of amino acids to glucose |
|
|
Term
| What effect does caffeine have on PKA? |
|
Definition
| Caffeine inhibits phosphodiesterase, which breaks down cAMP- as a result, cAMP stays around and accumulates, constantly activating PKA |
|
|
Term
| What is the effect of PKB on glucose transporter GLUT4? |
|
Definition
PKB stimulates the movement of GLUT4 from the internal membrane vesicles to the plasma membrane
INCREASING THE UPTAKE OF GLUCOSE |
|
|
Term
| What organ has the highest glucose demand in the basal state? |
|
Definition
|
|
Term
| Why doesn't glucagon release alter muscle metabolism? |
|
Definition
| Muscles lack the glucagon receptor |
|
|
Term
| What is the effect on the liver of a high intake of caffeine? |
|
Definition
| Prolonged response to glucagon via prolonged activation of PKA (no breakdown of cAMP) |
|
|
