lipids

Question 1

give the 4 types of lipids

Answer 1

triglycerides, phospholipids, steroids, waxes

Question 2

are lipids defined in terms of solubility or structure

Answer 2

solubility

Question 3

why are lipids insoluble in water?

Answer 3

they lack a polar head

Question 4

what are the 4 functions of lipids

Answer 4

energy storage as adipose tissue, insulation + protection, component of cell membranes, intercellular messages

Question 5

where can lipids be found in the nervous system

Answer 5

myelin sheath

Question 6

give some organismal uses of fats, oils, phospholipid, steroids and waxes

Answer 6

fats: long term energy storage + insulation in animals, oils: long term energy storage + insulation in plants, phospholipid: component of plasma membrane, steroids: hormones + plasma membrane, waxes: myelin sheath, wear resistance, retain water

Question 7

describe the structure of a saturated fatty acid

Answer 7

no double bonds between the carbon atoms, straight chains, chains can be packed together (lie flat) in adipose tissue

Question 8

describe the structure of a glycerol

Answer 8

a three carbon compound with three hydroxyl groups

Question 9

is glycerol soluble in water

Answer 9

yes- it has polar hydroxyl groups

Question 10

what sort of bond joins lipids together

Answer 10

ester bonds

Question 11

how is a fat formed

Answer 11

via a condensation dehydration reaction between the acid portion of three fatty acids and the hydroxyl groups of glycerol

Question 12

why are fats and oils often called trigylcerides

Answer 12

the presence of three fatty acids and one glycerol

Question 13

is animal fat solid or liquid at room temp

Answer 13

solid

Question 14

is plant fat solid or liquid at room temp

Answer 14

liquid

Question 15

how are triglycerides generally used in plants and animals

Answer 15

long term storage

Question 16

describe the structure of a wax

Answer 16

a long chain of fatty acids bonded with a long chain alcohol

Question 17

what is the function of a wax

Answer 17

protection- ie waxy cuticle on leaves or ear wax in humans and animals

Question 18

do waxes have a high or low melting point

Answer 18

high

Question 19

what is the main function of phospholipids

Answer 19

they form the core of all biological membranes

Question 20

what is an individual phospholipid made of

Answer 20

glycerol, 2 fatty acids and a phosphate group

Question 21

what are phospholipids derived from

Answer 21

triglycerides

Question 22

are the fatty acids in phospholipids polar or non polar

Answer 22

non polar

Question 23

is the phosphate group in phospholipids polar or non polar

Answer 23

polar

Question 24

what part of the phospholipid determines the surface properties of membranes

Answer 24

the head groups

Question 25

what is in the basic structure of a steroid

Answer 25

4 fused carbon rings

Question 26

what is the precursor steroid for many other steroids

Answer 26

cholesterol

Question 27

how do steroids differ primarily from each other

Answer 27

the types of functional groups