chapter 3- lipids

Question 1

what are the chemical elements that make up lipids

Answer 1

hydrogen, carbon and oxygen

Question 2

what is the structure of a triglyceride

Answer 2

a molecule made up of 1 glycerol and 3 fatty acids

Question 3

what bond forms when a fatty acids combines with a glycerol, and what is the name of this reaction

Answer 3

ester bond in the reaction called esterification

Question 4

what is a saturated fatty acid

Answer 4

a fatty acid with NO double bonds between carbon atoms

Question 5

what is an unsaturated fatty acid

Answer 5

it has one or more double bond between carbon atoms

Question 6

what is the strcuture of a phospholipid

Answer 6

a molecule with 2 fatty acids and a phosphate group bonded to one molecule of glycerol formed by condensation reactions

Question 7

what is the type of reaction used to break down phospholipids to release phosphate

Answer 7

hydrolysis, it uses water and can break down the ester bond

Question 8

what does hydrophilic mean

Answer 8

attracted to and soluble in water (water loving)

Question 9

define hydrophobic

Answer 9

repelled by and insoluble in water (water hating)

Question 10

what are lipids made up of

Answer 10

made up of a mix of different, smaller molecules, joined together.

Question 11

what are fatty acids

Answer 11

a smaller structure that can form a part of a lipid.

Question 12

name one example of a lipid

Answer 12

triglycerides

Question 13

fatty acids are made up of a

Answer 13

hydrocarbon chain that is attached to a carboxyl group

Question 14

what is the common abbreviation for fatty acid

Answer 14

RCOOH
R for residual group or hydrocarbon chain and COOH for carboxyl group

Question 15

triglycerides form in what type of reaction

Answer 15

condensation reactions which release water

Question 16

explain if triglycerides are polymers

Answer 16

no because they are formed of 3 fatty acids and one glycerol molecule not repeating units of a single monomer

Question 17

if fatty acids are added to a solution what will happen to the pH

Answer 17

it will decrease as fatty acids are acidic and so the concentration of acidic will increase

Question 18

a fatty acid with one double bond is called a

Answer 18

monounsaturated fatty acid

Question 19

a fatty acid with more than one double bond is called a

Answer 19

polyunsaturated fatty acid

Question 19

how does the structure of fats contribute to their state at room temperature

Answer 19

fats are made up of saturated fatty acids which have STRAIGHT parallel hydrocarbon chains, this triglycerides dont take up a lots of space=tightly packed together=solid @ room temp

Question 20

how does the structure of an oil contribute to their state at room temperature

Answer 20

oils are made up of unsaturated fatty acids/triglycerides which have BENDS in their hydrocarbon chains due to the C double bond (unsaturated) these take up a lot of space=not tightly packed=liquid @ room temp

Question 21

what is a function of triglycerides (3/4)

Answer 21

it is an energy storage molecule/source of energy, electrical insulation, thermal insulation

Question 22

what is a property of triglycerides (3)

Answer 22

an insoluble molecule enabling it to be a good storage molecule, large, have a high C and H:O ratio

Question 23

triglycerides are a good energy storage molecule because they are…

Answer 23

large

Question 24

do triglycerides have a high carbon and oxygen: hydrogen ratio

Answer 24

NO they have a high carbon and hydrogen: oxygen ratio

Question 25

how do the properties of triglycerides suit its function as an energy source

Answer 25

Triglycerides have fatty acid tails which have a high ratio of carbon and hydrogen to oxygen, so they can release high amounts of energy via respiration to release large amounts of ATP.

Question 26

how do triglycerides provide thermal insulation

Answer 26

triglycerides stored beneath our skin form a layer that provides thermal insulation which prevents the escape of heat from our bodies

Question 27

how do triglycerides provide electrical insulation

Answer 27

they are wrapped in layers around our nerve cells providing electrical insulation which prevents the escape of electrical impulses into surrounding cells

Question 28

phospholipids and triglycerides are insoluble in ….. and soluble in ..

Answer 28

water and ethanol

Question 29

why are T AND P soluble in ethanol

Answer 29

ethanol (an alcohol) its NON-POLAR, non polar substances are able to mix together so T AND P are able to dissolve in alcohols such as ethanol

Question 30

why is ethanol non polar

Answer 30

This is because, although ethanol has a small polar region, the bulk of it is made up of a non-polar region.

Question 31

what is the test used to determine if a lipid is present

Answer 31

the emulsion test