lipids

Question 1

define: lipids

Answer 1

• non soluble in polar substances

- soluble in aprotic organic substance

Question 2

categories of lipids?

Answer 2

triglycerides, phospholipids, steroids

Question 3

describe fatty acids

Answer 3

long hydrocarbon chains (unsaturated or not) with COOH. usually even no c’s

Question 4

relate lipid structure to props

Answer 4

increased length and increased saturation = higher mp

Question 5

describe trans fats

Answer 5

usually double bonds form cis conformation but occasionally trans, also artifically by hydrogenation. reduces oxidative rancidity. but enzymes cant break down so aggregates leading to atherosclerosis

Question 6

describe triglycerides

Answer 6

ester formed by condensation of glycerol and 3fa’s (forms 3H2O)

Question 7

how are triglycerides turned into soaps

Answer 7

via saponification. add NaOH -> forms —COO-Na+ and glycerol
-forms micelles, enabling lipid soluble fats/grease to dissolve in HC chain.

Question 8

describe detergents

Answer 8

soaps but with So3- group instead of COO- as more water soluble

Question 9

describe phospholipids

Answer 9

(glycerol + f fa’s + phosphoric acid)phosphatidic acid esterified with low weight alcohol

Question 10

how do phospholipids aggregate

Answer 10

into plb via hydrophobic effect and electrostatic interactions

Question 11

descirbe fluid mosaic model

Answer 11

• fa chains are fluid so proteins float freely through them

- there are discrete components embedded in the bilayer. they’re separat!

Question 12

describe steroids

Answer 12

plant/animal molecuels that are tetracyclic structures (2 hexagons 2 pentagons)

Question 13

whats the precursor to all steroids?

Answer 13

cholesterol!!

Question 14

examples of steroids?

Answer 14

androgen estrogen anabolic steroids
bile acids
glucocorticoid hormones
mineral cortocoid hormones