lipids

Question 1

Heterogenous class id naturally occurring organic compounds classified tgt in the basis of common solubility properties

Answer 1

Lipids (fats and oils)

Question 2

lipids
soluble:
insoluble:

Answer 2

soluble: aprotic organic solvent (diethyl ether, chloroform, acetone, methylene chloride)
insoluble: water bcs of their v. large hydrocarbon chain

*due to their structure

Question 3

structure of lipid

Answer 3

dominant: water is polar
C-C
C-H

may have:
O-H
P

Question 4

miscible

Answer 4

soluble

Question 5

molecule that has one end with a polar, water soluble group and other end with a nonpolar HC grp that is insoluble in water

Answer 5

amphipathic

has polar and nonpolar parts
*dominant: np, esp in water

Question 6

classification of lipids
- open chain compounds:
- fused ring compounds:

Answer 6

open chain compounds: (mas varying daw)
fatty acids
TG
sphingolipids
phosphoacylglycerols
glycolipids

fused ring compounds:
cholesterol
steroid hormones
bile acids

Question 7

unbranched chain carboxylic acids

Answer 7

fatty acids
12-20 long (even no. of carbons)
derived from hydrolysis (of animal fats, vege oils etc)

hydrolysis - breakdown of water

Question 8

amphitic compounds of fatty acids
nonpolar
polar:

Answer 8

nonpolar: HC
polar: COOH

Question 9

types of fatty caids
contain c=c:
contain c-c:

Answer 9

contain c=c: unsaturated
contain c-c: saturated

Question 10

in unsaturated fatty acids,
cis isomer predominated
trans isomer is rare

Answer 10

cis isomer predominated:
same side

trans isomer is rare:
diff side

Question 11

melting point of the fatty acids depends on the

Answer 11

length of chain
degree of unsaturation (no. of double bonds)

Question 12

is an unsaturated fatty acid with its endmost double bond three carbon atoms away from methyl end

Answer 12

omega 3 fatty acids

Question 13

it is accumulated in adipose tissues and provide a means of storing fatty acids

Answer 13

triacylglycerols (triglycerides)

ester linkage are hydrolyzed by lipase
stores oof metabolic energy

Question 14

reaction of glyceryl ester with NaOH or KOH t produce glycerol and respective Na or K salts

Answer 14

saponification

Question 15

compounds in which 2 fatty acids and phosphoric acid are esterified to the 3 hydroxyl grps of glycerol

Answer 15

phosphatic acid

Question 16

why is the head of the fatty acids are charged

Answer 16

as it contains phosphate group - that ionized at neutral pH

*positively charged amino grp by an amino alcohol esterified to the phosphoric acid

Question 17

complex mixtures of esters of long chain carboxylic acid and long chain alcohols

Answer 17

waxes
*serve as a protective coating for plants and animals

Question 18

primary alcohol of sphingosine is esterified to phosphoric acid which is esterified to choline

Answer 18

sphingomyelin

Question 19

lipid to which a sugar moiety is bonded

Answer 19

glycolipids

Question 20

parent compound of glycolipids

Answer 20

ceramides

Question 21

it is formed between the pri alcohol grp of ceramide and a sugar residue (glucose or galactose )

Answer 21

glycosidic bond

= result compound called a cerebroside

Question 22

glycolipids with a complex carbs moiety that contains 3 sugars

Answer 22

gangliosides
-one is always a sialic acid
-has negative charge at neutral pH

Question 23

lipids with a characteristics fused-ring structure

Answer 23

steroids

Question 24

where does cholesterol occur

Answer 24

cell membrane
- highly hydrophobic
- precursors: can derive to t=other structures

Question 25

what is the major force that is driving the formation of lipid bilayers

Answer 25

hydrophobic interaction

Question 26

membrane fluidity linear arrangement of HC chain leads to rigidity - kink in the HC chain causes disorder in its packaging in and leads to greater fluidity -

Answer 26

linear arrangement of HC chain leads to rigidity - saturated fatty acids (rigid = cant movee) kink in the HC chain causes disorder in its packaging in and leads to greater fluidity - unsaturated fatty acids (has bends and have spaces between FAs = more loose packing = greater fluidity)

Question 27

true or false: presence of cholesterol can enhance order and rigidity

Answer 27

true as fused ring of cholesterol is rigid

Question 28

true or false: plant membrane are less fluid and more rigid than animal membrane

Answer 28

false animal membrane (contain cholesterol ) are less fluid and more rigid than plant membrane (hv unsaturated fat)

Question 29

true or false: membranes oof prokaryotes are the most fluid

Answer 29

true most - least prokaryotes > plants > animals

Question 30

true or false: ordered bilayers become more ordered in the presence of heat

Answer 30

false - loosely packed high temp, high fluid gel > liquid (in the presence of heat)

Question 31

this type of protein is loosely bound to the outside of a membrane

Answer 31

peripheral proteins (Heterotrimeric G protein)

Question 32

this type of proteins are embedded in a membrane

Answer 32

integral proteins (Rhodopsin) * can be removed y treatment with detergents or extensive = denaturation of protein

Question 33

what type of bonds can do proteins anhored to the lipids

Answer 33

covalent bonds

Question 34

transport proteins: receptor proteins:

Answer 34

transport proteins: mediate the entry of specific substances into a cell receptor proteins: contains specific binding sites for extracellular subs

Question 35

model in which proteins and a lipid bilayer exist side by side without covalent bonds between them

Answer 35

fluid-mosaic model

Question 36

term that implies that there is lateral motion of components in the membrane

Answer 36

fluid mosaic

Question 37

process by which a substance enters a cell w/o expenditure of cell energy

Answer 37

passive transport *driven by conc. gradient - from high to low

Question 38

what are the 2 categories of passive transport

Answer 38

simple diffusion: dont need anything daw without requirement for a carrier facilitated diffusion: binding a carrier protein does not require energy

Question 39

substances is moved against a conc gradient

Answer 39

active transport *need energy from low to high pri active transport: directly linked to hydrolysis like ATP sodium-potassium ion pump sec active transport: driven by H+ gradient proton pump

Question 40

it is a principal carrier of cholestrol in the bloodstreem

Answer 40

low-density lipoprotein (LDL) consists of various proteins and lipids

Question 41

lipid soluble vitamins

Answer 41

hydrophobic vitamin A D E K