Lipids – Chemistry Test Questions – Flashcards
Unlock all answers in this set
Unlock answersquestion
Lipid |
answer
group of biological molecules of varying composition that are all soluble in non polar solvents. |
question
Fatty Acid |
answer
Long hydrocarbon chains that ends with a carboxylic acid group. (-cooh) |
question
Saturated Fatty Acid |
answer
Long chain monocarboxylic acids. contain only carbon to carbon single bonds and carbon hydrogen bonds. General Formula CH3(CH2)nCOOH |
question
Unsaturated Fatty Acid |
answer
Long chain monocarboxylic acids that contain one or more carbon to carbon double or triple bonds. |
question
Phospholipid |
answer
Combination of a lipid and a phosphate group. Major form of lipid in cells. |
question
Phophogylceride |
answer
Phospholipids derived from a gylcerol. |
question
Steroid |
answer
nautrally occurring family of lipids. Every steroid contains the same 17 carbon skeleton that spans 4 fused rings. Also, two methyl groups. |
question
Cholesterol |
answer
A common fat like sterpid nased alcohol found in animal fats. |
question
Triglyceride (TG) |
answer
three mlecules of fatty acids esterfied to glycerol. Also called triacylglycerols. |
question
Gylcerol |
answer
liquid alcohol often found as a component of fat or triglycerides. structural backbone onto which fatty acids attatch. |
question
Lipoprotein |
answer
Combination of lipid(s) and a protein(s). transportation from of lipids in the bloodstream. |
question
Apolipoprotein |
answer
protein component found in plasma lipoproteins. The wide variety of apolipoproteins give each lipoprotein a unique composition. |
question
Adipose |
answer
fat stored within the body. |
question
Lipase |
answer
enzyme that hydrolyzes the ester linkage between glycerol and the fatty acids of triglycerides. |
question
Glycolipids |
answer
Combination of a lipid and a carbohydrate group. i.e. brain and nervous tissue. |
question
Functions of Steroids |
answer
critical component of membranes, important to maintain membrane fluidity. serve as hormones and intergral component of bile acids. |
question
What is the most important steroid in animals? Why? |
answer
Chloesterol, because it is a major component of cell membrane and provides membrane fluidity. |
question
Cortisol |
answer
hormone secreted by the adrenal glad, helps the body deal with stress by raising glucose levels, increasing lipolysis, and depressing the immune system. |
question
anabolic steroids |
answer
resemble testosterone, artificially stimulate the body to increase the amount of muscle mass, stimule the healing of muscle and incress competitive aggressiveness. |
question
Major Lipids of the body |
answer
fatty acid, glycerol, cholesterol, phospholipids, monoglycerides, diglycerides, fat soluble vitamins, steroids. |
question
How much does fat does the average person injest per day? |
answer
60-130g of fat, mostly in the form of triglycerides, human body absorbs nearly 100% of fats injested. |
question
What are lipids found in foods composed of? |
answer
98-99% triglyceride, of which 92-95% is fatty acid, the remainder is glycerol. |
question
Biosynthesized Lipids |
answer
Fatty acids are synthesized in the cytoplasm of the cells of the liver, kidney, brain, lung and adipose tissue. |
question
How are lipoproteins classifed? |
answer
Based upon their distinctly different densitites after high speed ultracentrifugation |
question
Chylomicrons |
answer
largest and least dense of the lipoprotein, formed after ingestion of dietary fat, in the intestinal mucosam, transport dietary lipids to the liver, causes lipemia. |
question
Very Low-Density Lipoproteins (VLDL) |
answer
synthesized in the liver, transport TGs produced in the liver to extrahepatic tissues. |
question
Low-Density Lipoproteins(LDL) |
answer
transport cholesterol and cholesteryl to peripheral tissues and regulate synthesis of cholesterol. "bad cholesterol". |
question
High-Density Lipoproteins (HDL) |
answer
synthesized in the liver, transports cholesterol back to the liver for excretion. smallest and most dense lipoprotein particle. "good cholesterol" |
question
Beta Oxidation Pathway Definition |
answer
series of biochemical reactions whihc fatty acids are completely oxidized in the mitochondrial matrix, resulting in significant amounts of ATP. |
question
Beta Oxidation STEPS |
answer
1)each fatty acid molecule is bound to a CoA molecule. 2)each passage results in the production of a single 2 carbon acetyl CoA and a new fatty acid CoA that has two fewer carbons. 3) the two carbon CoA are consumed in the Krebs Cycle and result in production of ATP. |
question
Other than ATP what is produced in the Beta Oxidation Pathway? |
answer
two high-energy electron carries (1 NADH + 1 FAD2H). They enter the mitochondrial electron transport change and are used to make more ATP |
question
What happens to excess Acetyl-CoA? |
answer
They are converted into molecules called ketone bodies. |
question
Ketone Bodies |
answer
Beta-Hydroxybutyrate, acetone, and acetoacetate. CAn be used as fuel by most tissues, and certain organs. |
question
Ketosis |
answer
Excess levels of ketone bodies in the bloodsream. |
question
CAuses of ketosis |
answer
low carb diet, starvation, uncontrolled diabetes mellitus. |
question
Ketoacidosis |
answer
often accompanies ketosis. Beta-hydroxybutyrate and acetoacetate are strong acids that can alter blood Ph. |
question
What are the steps involed in the anabolism of lipids? |
answer
The precuresor of synthesis is Acetyl-CoA, each molecule is made by the sequential addition of acetyl groups (2 carbons). Fatty acids can ezymatically combine with glycerol to make TGs |
question
Where does synthesis of fatty acids occur? |
answer
Within the cytosol of cells. |
question
Pancreatic Lipase |
answer
removes fatty acids from dietary lipids resulting in more polar compounds with ampipathic properties. |
question
Emulsification |
answer
polar agents cover small fat particles and prevent monoglycerides, free fatty acids and glycerol. |
question
Sources of Lipase within the body |
answer
Pancreas (primary source) Salivary Galnds (lingual lipase) |
question
Clinical Significance of elevated Lipase |
answer
acute pancreatitis, pancreatic carcinoma. |
question
Test methodolgy of Lipase |
answer
Measures the fatty acid that is produced by the catalysis of Lipase. |
question
Chylomicron Remnant |
answer
remainder of chylomicrons after exposure to LPL |
question
about 95% of Bile acids are? |
answer
reabsorbed and reused by the liver to support bile production. |
question
Steps in the metabolism of Dietary Lipoproteins |
answer
1) new chylomicrons are secreted into the lymphatic ducts and enter the blood. 2) LPL hydrolyzes triglycerides in chylomicrons. 3) resulting fatty acids and glycerol are taken up by cells and used as energy. 4) excess fatty acids are re-esterfied into triglycerides for long-term storage. |
question
Steps in metabolism of lipoproteins of hepatic origin |
answer
1)VLDL is syntheszied in the liver and secreted into circulation where they undergo lipolysis. 2) VLDL loses core lipids causing dissociation and transfer of lipoproteins and phospholipids. 3) VLDL remnants are further transformed into LDL in the liver. 4) Once LDL is bound to receptors they are endocytosed and transported to the lysosome. 5) triglycerides in LDL are converted into free fatty acids and glycerol. 6) fatty acids are metabolized for energy. 7) free cholesterol is used for membrane biosynthesis. |
question
Reverse Cholesterol Pathway |
answer
mediated by HDL maintains cholesterol equilibrium. excess cholesterol is transported back to the liver by HDL, where it is excreted into bile as free cholesterol, or excreted after being converted to bile acids. |
question
3 forms of Hyperlipidemia |
answer
Hypertriglyceridemia, Hypercholeserolemia, Hyperlipoproteinemia. |
question
Hypertriglyceridemia |
answer
elevated levels of TGs. Results from abnormal lipid metabolism or abormal forms of VLDL. Serum TG >500mg/dL |
question
Hypercholesterolemia |
answer
increased level of cholesterol. contributor to atherosclerosis and CAD. abnormally high serum LDL. Common inherited disorder caused by defective or absent LDL receptors. |
question
Hyperlipoproteinemia |
answer
increased level of specific lipoproteins. acquired or inherited. caused by underlying diseases, medications, genetic mutations, or poor diet. |
question
Hypolipoproteinemia |
answer
very rare condition caused by a decreased level of lipoprotein. |
question
Atherosclerosis |
answer
Deposition of lipids, especially cholesterol, in arterial walls. |
question
Atherosclerosis - Disease Process |
answer
1)lipid deposition starts with fatty streaks. 2) blood traveling causes small injuries that signal macrophage and platelets. 3) LDL brings cholesterol and a fibrous plaque develops. 4) LDL that has been modified is taken up by macrophages and transform into foam cells. 5) continuous injurt and repair leads to additonal narrowing and increased pressure causing disease. |
question
Coronary Artery Disease |
answer
major fibrous plaque develops in the artiers of the heart. (Heart Attack) |
question
Peripheral Vascular Disease |
answer
major fibrous plaque develops in the arteries of the arms or legs. |
question
Cerebrovascular disease |
answer
majorfibrous plaque develops in the vessels of the brain. (Stroke) |
question
What is the most common type of heart disease? |
answer
Coronary Artery Disease, it is the leading cause of death in both men and women in the US. |
question
What are the possible effects of reduced or cut-off blood supply to the heart? |
answer
Angina, HEart Attack aslo known as Acute Myocardial Infarction, HEart Failure, Arythmias. |
question
Elevated LDL and Triglyceride |
answer
high risk of cardiac disease. |
question
High HDL concentration |
answer
decreased risk of cardiac disease. |
question
Low HDL concentrations |
answer
increased risk of cardiac disease. |
question
Elevated Triglyceride |
answer
contributor to cardiac disease. |
question
Total Cholesterol - Enzymatic Method |
answer
quantitation of all the colesterol and colesterol esters present. |
question
PRinciple of Total Cholesterol |
answer
hydrolysis of cholesterol esters yiel cholesterol and free fatty acids. Oxidation of total cholesterol yields Hydrogen peroxide,which is oxidatively coupled to 4-aminoantipyrine. When peroxidase is added it forms a product that absorbs light at 500nm. |
question
Friedewald Formula Part 1: |
answer
VLDL cholesterol = Triglyceride / 5 |
question
Friedewald Formula Part 2 |
answer
LDL cholesterol = Total Cholesterol - (VLDL Cholesterol + HDL cholesterol. |