Lipids

Question 1

give an overview of lipids

Answer 1

• not classified by functional group
• insoluble in water
• can be extracted from biological tissues using non-polar solvent
• hydrophobic or amphiphathic

Question 2

define amphipathic

Answer 2

both non and polar

Question 3

what are common functions of fats

Answer 3

• energy store
• membranes
• insulation

Question 4

what are the main classes of lipids

Answer 4

• polyprenyl compounds
• triglycerides
• glycolipids
• phospholipids
• sphingolipids
• waxes

Question 5

what is the structure of fatty acids

Answer 5

• carboxylic acid head
• long chain hydrocarbon tail
• can be saturated or not

Question 6

what happens in the structure of trans fats

Answer 6

nothing

Question 7

what happens in the sturcture of cis fats

Answer 7

bent configuration

Question 8

what causes a difference in fatty acids

Answer 8

• length of hydrocarbon
• degree of saturation
• position of double bonds

Question 9

describe saturated fats

Answer 9

-no double bonds
-high melting point
-solid at room temp
written as 12:0 for 1 carbon fat

Question 10

describe unsaturated fats

Answer 10

-mono or poly saturated
-low melting point
-liquid at room temp
written as 20:4Δ5,8,11,14

Question 11

how to name fatty acids

Answer 11

-oic acid

total carbon, double bonds, cis or trans

Question 12

what happens with cis fatty acids

Answer 12

bent structure means its abrupt and more likely to be liquid

Question 13

what are LDL’s

Answer 13

low density lipoproteins cholesterol

Question 14

what are HDL’s

Answer 14

high density lipoproteins cholesterol

Question 15

what does HDl do

Answer 15

tags fat to be transported to the liver to be broken down

Question 16

what does LDL do

Answer 16

tag fat but stays in arteries

-cause coronary heart disease

Question 17

what are triglycerides

Answer 17

molecules made of glycerol esterified with three fatty acids (same or different)

Question 18

examples of triglyceries

Answer 18

adipose tissue, hepatic lipids

Question 19

how is soap made

Answer 19

hydrolysis of triglycerides with alkali- saponication

Question 20

changing physcial properties with triglycerides:

Answer 20

• carbon # increase = melting point increases

- double bond# increases, melting point decreases

Question 21

what is the structure of phosphoglyceries

Answer 21

• glycerol
• 2 long chain hyrocarbons on c1&”
• phosphoric acid esterfied to C3 hydroxyl group
• the head can have different groups on phosphate

Question 22

phospholipids in water

Answer 22

• plasma membrane

- hydrophobic effect causes bilayer

Question 23

polarity of phospholipid

Answer 23

polar head

nonpolar tail

Question 24

overview on waxes

Answer 24

• esters of long chain alcohols with long chain fatty acids
• water resistant
• don’t form chemically homogenous groups
• include alkanes, alkenes, ketones

Question 25

overview of sphingolipids

Answer 25

Found in membranes especially brain cells and nerve cells They don't contain glycerol The backbone has who hydroxyls and an amide group/ amine R chain Helps in the cellular uptake of fatty acids Sphingomyelins make up 25% of myelin sheaths

Question 26

overview of terpenes

Answer 26

hydrocarbon compounds constructed from five-carbon isoprene units that are combined to produce a great variety of skeletons, which are then acted upon by various enzymes to add functionality and altered oxidation --> isoprene = single unit Found in essential oils Flavours an smells

Question 27

overview of diterpenes

Answer 27

Two terpene units Anti-inflammatory and antimicrobial Basis for compounds like phytol an retinol (vitamin A1)

Question 28

overview of steroids

Answer 28

Different to other lipids as it has 4 rings --> 3 cyclohexane --> 1 cyclopentane They can have a variety of attached functional groups Still has large amount of C-H so is nonpolar Examples are cholesterol, testosterone, and estrogen

Question 29

why are lipids used for cell surface membranes

Answer 29

- separates internal and external environment - fluid - keeps water inside