click below
click below
Normal Size Small Size show me how
CHM 140
CH 21
Question | Answer |
---|---|
lipid | heterogeneous class of naturally occurring organic compounds classified together on the basis of common solubility properties |
hydrophilic | "water loving" usually used to describe a polar molecule or the polar portion of a molecule that is soluble in water |
hydrophobic | "water hating" usually used to describe a nonpolar molecule or the nonpolar portion of a molecule that is insoluble in water |
hardening | industrial process for reducing the number of double bonds in oils by partial hydrogenation (adding hydrogens) creating a more solid product. |
micelle | a globular cluster of molecules with the hydrophobic ends toward the center of the globule and hydrophilic end near the exterior at the globule-water interface |
glycolipid | a lipid attached to a carbohydrate |
androgens | male sex hormones |
estrogens | female sex hormones |
mineralcorticoid | hormones that enhance Na+ and Cl- ion reabsorbtion by the kidney and increases the loss of K+. |
glucorticoid | regulate metabolism of carbohydrates-increase glucose and glycogen concentration in the body also decrease inflammation |
What are the 3 major roles of lipids? | a) energy storage, b) component of cell membranes, c) chemical messengers (hormones and secondary messangers) |
Where are triglycerides mainly found in the body? | adipose tissue (fat cells) |
Why do triglycerides with mainly saturated fatty acids chains have a higher melting point than triglycerides with a high percentage of unsaturated fatty acids? | Saturated fatty acids chain stack neatly creating a more crystalline structure with a higher M.P. |
Margarine which is semisolid is made up of oils from corn, soybean, peanut, etc. How does industry turn the oil into semisolids? | Through a process called hardening -partial hydrogenation of some of the double bonds |
What are the two different components of a triglyceride? | glycerol and fatty acids |
How do soaps clean dirt particles out of materials? | They form micelles around the dirt particle carrying it away in water |
How does hard water decrease the cleansing action of soaps? | The cations in hard water (calcium and magnesium) form water insoluble salts with soap. |
What is the basic structure of a phosphoglyceride? What are the R groups attached to the phosphate group? | Two fatty acids, glycerol, and a phosphate ester with an alcohol which is either choline, serine, ethanolamine, or inositol. |
Draw a schematic of the arrangement of phosphoglycerides in a cell membrane using the head and tails model. | |
What are the 3 classes of sphingolipids? | sphingomyelin, cerebrosides, and gangliosides |
Where is sphingomyelin found? | in the myelin coating in nerve cells |
Where are the cerebrosides found? | in cell membranes in the brain |
What is the function of gangliosides? | component of specific receptor on the surface of cell membranes |
Draw the basic 4 ring structure of steroids. | |
Describe how cholesterol is transported from the liver to the peripheral tissue cells. | Leaves liver as VLDL composed of cholesterol esters and triglycerides (TG). TG deposited in fat cells, VLDL becomes LDL. The LDL binds to specific receptors on the cell surface and enters the cells where it is broken down to cholesterol and its esters. |
What are the two main male sex hormones? What are their function? | testosterone and androsterone-responsible for development of secondary sexual characteristics |
What are the two main female sex hormones? What are their two functions? | estradiol and progesterone-development of secondary sexual characteristics and control of the menstrual cycle. |
What is the function of aldosterone? | a mineralcorticoid-enhances Na+ and Cl- reabsorbtion and increased excretion of K+ by the kidneys. |
What are the two main glucorticoids? What are their two main functions? | cortisone and cortisol-a) increase glucose and glycogen levels b) given to fight inflammation |
What are the two main functions of bile salts? Where are bile salts synthesized? Where are they stored? | a) elimination route of cholesterol b) emulsify fats and aid their absorbtion in the intestines |
What precursor is prostaglandins, thromboxanes, and leukotrienes synthesized from? | Arachidonic acid - a 20 carbon unsaturated fatty acid |
What is the function of thromboxanes in the blood? | induces platlets aggregation and vessel constriction |
The synthesis of leukotrienes cause what effect on muscle tissue? | produce muscle contractions |
Both prostaglandins and leukotrienes cause what physiological response at an injury site? | inflammation |
What are the two main functions of cholesterol? | a) component of cell membranes b) precursor for hormones and bile salts |
What is meant by "good cholesterol"? | HDL is termed "good" because it transports cholesterol to the liver for excretion as bile salts and formation of hormones thus reducing serum levels |
What is meant by "bad chloesterol"? | LDL is termed "bad" because high levels of it means that not enough LDL is being absorbed into the cells and is remaining in the serum where it could deposit on the walls of blood vessels causing artherosclerosis. |