Carbohydrates, lipids and water

Question 1

What is maltose?

Answer 1

disaccharide formed by condensation of two glucose molecules

Question 2

what is sucrose?

Answer 2

disaccharide formed by condensation of glucose and fructose

Question 3

what is lactose?

Answer 3

disaccharide formed by condensation of glucose and galactose

Question 4

what are the two isomers of glucose

Answer 4

beta and alpha

Question 5

what is glycogen and starch formed by

Answer 5

the condensation of alpha glucose

Question 6

what is cellulose formed by

Answer 6

the condensation of beta glucose

Question 7

what is a monomer

Answer 7

small units from which larger molecules are made

Question 8

what is a polymer

Answer 8

molecules made from a large number of monomers joined together

Question 9

what is a condensation reaction

Answer 9

joins two molecules together with the formation of a chemical bond and involves the elimination of a water molecule

Question 10

what is a hydrolysis reaction

Answer 10

breaks a chemical bond between two molecules and involves the use of a water molecule

Question 11

what are two groups of lipid

Answer 11

triglyceride and phospholipids

Question 12

how is a triglyceride formed

Answer 12

condensation of one molecule of glycerol and three molecules of fatty acid

Question 13

condensation reaction between glycerol and a fatty acid forms a what

Answer 13

an ester bond

Question 14

what can the r group in a fatty acid be

Answer 14

saturated or unsaturated

Question 15

what happens in a phospholipid that is different from a triglyceride

Answer 15

one of the fatty acids of a triglyceride is substituted by a phosphate-containing group

Question 16

explain 5 properties water has that is important in biology

Answer 16

1. a metabolite - water can be involved in metabolic reactions such as condensation and hydrolysis
2. a solvent - allows metabolic reactions to occur and allows the transpor of substances
3. high specific heat capacity - buffers changes in temperature
4. large latent heat of vaporisation - provides a cooling effect
5. cohesion - supports the formation of continuous columns of water. Produces surface tension which supports small organisms

Question 17

what are organic molecules

Answer 17

molecules with carbon-carbon and carbon-hydrogen bonds

Question 18

name 3 monosaccharides

Answer 18

glucose
fructose
galactose

Question 19

name 3 disaccharides

Answer 19

maltose
lactose
sucrose

Question 20

name 3 polysaccharides

Answer 20

starches
cellulose
glycogen

Question 21

what does saccharide mean

Answer 21

sugar

Question 22

whats the molecular formula for glucose

Answer 22

c6h12o6

Question 23

what is formed when two monosaccharides join together in a condensation reaction

Answer 23

glycosidic bond

Question 24

what is a polysaccharide

Answer 24

type of polymer formed by joining many monosaccharides (3+) together by condensation reactions

Question 25

what is an example of a storage polysaccharide in plants

Answer 25

starch

Question 26

explain 4 structure features of starch and how it helps its function

Answer 26

1)helical structure which makes it compact allowing many alpha glucose molecules to fit into a small area 2)branched structure which gives it a larger surface area allowing for faster enzyme action 3)large so it cant diffuse out of cells 4)insoluble so doesn't affect water potential

Question 27

explain 3 structure features of glycogen and how it helps its function

Answer 27

1)coiled making it compact allowing many alpha glucose molecules to be packed together 2)insoluble so doesn't affect water potential 3)large molecule so it cannot cross the cell membrane and diffuse out of cells

Question 28

give 3 ways glycogen has specific adaptations compared to starch

Answer 28

1)shorter chains 2)more highly branched 3)larger surface area

Question 29

what is cellulose a polymer of

Answer 29

beta glucose

Question 30

where is cellulose found

Answer 30

plant cell walls

Question 31

where is the OH group in alpha glucose

Answer 31

below

Question 32

where is the OH group in beta glucose

Answer 32

above

Question 33

explain how celluloses structure helps its function

Answer 33

-Several chains of cellulose are joined together into layers by weak hydrogen bonds -this forms microfibrils which wound together to form cellulose fibres -these fibres provide rigidity/strength and support to the cell wall

Question 34

what are the three different tests for carbohydrates

Answer 34

1)benedicts test for reducing sugar 2)benedicts for non-reducing sugar 3)iodine test for starch

Question 35

name 5 reducing sugar

Answer 35

1)glucose 2)galactose 3)lactose 4)maltose 5)fructose

Question 36

name a non-reducing sugar

Answer 36

sucrose

Question 37

explain the benedicts test method for reducing sugar

Answer 37

1)add equal volume of benedicts solution and sample to a test tube 2)heat to 95 degrees 3)if there is a reducing sugar there will be a formation of a brick red precipitate

Question 38

explain the benedicts test for non-reducing sugar

Answer 38

1)boil a fresh sample with hydrochloric acid for 5 minutes 2)neutralise the solution by adding sodium hydrogen carbonate 3)then follow the same steps as reducing sugar

Question 39

why do you use hydrochloric acid for the non-reducing benedicts test

Answer 39

it hydrolysis the glycosidic bond to produce glucose and fructose which are both reducing sugars

Question 40

what is the main role of lipids

Answer 40

main component of the cell surface membrane

Question 41

explain 3 other roles lipids have

Answer 41

source of energy- lipids provide twice as much energy as carbohydrates when they are oxidised insulation- fats dont conduct heat well protection- layer of fat surrounds organs

Question 42

how is a triglyceride formed

Answer 42

one molecule of glycerol joined to 3 fatty acids by a condensation reaction which forms 3 ester bonds between the carboxyl group of the fatty acid and the hydroxyl group of glycerol

Question 43

whats the difference between saturated and unsaturated fatty acids

Answer 43

saturated fatty acids have no double bonds between carbons. Unsaturated fatty acids have double bonds

Question 44

explain properties of tryglycerides

Answer 44

-triglycerides are hydrophobic -contain a lot of energy -have a low energy:mass ratio making it excellen for storing energy(compact) -release water when oxidised

Question 45

explain the emulsion test for lipids

Answer 45

-add ethanol to sample and mix -add water and mix -if present a white emulsion will appear

Question 46

how is a phospholipid formed

Answer 46

1 glycerol joins to 2 fatty acids and 1 phosphate group by a condensation reaction

Question 47

how many bonds are in a: 1) triglyceride 2) phospholipid

Answer 47

1)3 ester bonds 2)2 ester bonds

Question 48

what are the 2 different parts of a phospholipid called

Answer 48

-hydrophilic head -hydrophobic fatty acid tail

Question 49

explain the hydrophilic head in phospholipids

Answer 49

it is attracted to water, so it interacts with it. This is caused by the polar(charged) nature of the phosphate group

Question 50

explain the hydrophobic tails in phospholipids

Answer 50

they are repelled by water and face away from it. This is because they are non-polar(not charged)