biological molecules-unit 2

Question 1

what is a condensation reaction?

Answer 1

a reaction that forms a bond between two molecules however it removes a molecule of water

Question 2

what is a polymer

Answer 2

a large long chain molecule comprised of many monomers joined together

Question 3

what is a hydrolysis reaction?

Answer 3

a chemical reaction that breaks a bond between two molecules by the addition of water

Question 4

what is the bond between two monosaccharides?

Answer 4

a glycosidic bond

Question 5

what are monomers of the disaccharide maltose

Answer 5

alpha glucose

Question 6

what is the test for sugars

Answer 6

add benedict’s reagent to sample and heat it will go red/orange/green if reducing sugar is present will remain blue if it is not present

Question 7

what is the test for starch?

Answer 7

add iodine to the sample if starch is present sample changes from a brown-orange colour to dark blue starch is present

Question 8

what is the test for lipids

Answer 8

dissolve sample with ethanol and shake then add to water if a white emulsion forms, a milky white emulsion will form

Question 9

what is the test for proteins?

Answer 9

add a few drops of sodium hydroxide solution
then add copper(II) sulfate solution
it will go purple if protein is present

Question 10

what is a peptide bond?

Answer 10

the bond between two amino acids

Question 11

what is the primary structure of a protein

Answer 11

the sequence of amino acids

Question 12

what is the secondary structure of a protein

Answer 12

the formation of alpha helicies and beta pleated sheets

Question 13

what is the teritary structure of a protien

Answer 13

the 3D folding into shape held together by various bonds e.g hydrogen bonds, disulfide bridges, covalent bons

Question 14

what is the quaternary structure of a protien

Answer 14

the addition of additional polypeptide chains or a prosthetic group

Question 15

what is the bond in a lipid

Answer 15

ester bond

Question 16

why aren’t lipids polymers

Answer 16

as they are not made from monomers

Question 17

name three roles of lipids

Answer 17

• waterproofing
• insulation
• source of energy

Question 18

name three characters of lipids

Answer 18

• the proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates
  -they are insoluble in water
  they are soluble in organic solvents such as alcohols and acetone

Question 19

what is an unstaurated lipid

Answer 19

a lipid that contains a carbon carbon double bond

Question 20

what is a saturated lipid

Answer 20

a lipid that does not contain a carbon carbon double bond

Question 21

how is starch adapted to it’s function? (4)

Answer 21

• it is insoluble so it is osmotically inactive
• it is compact so alot can be stored in small spaces
• it’s highly branched so it can be hydrolysed quickly to release glucose
• it is large so it won’t diffuse in and out of the cell

Question 22

how is glycogen adapted to it’s function?

Answer 22

compact
osmotically inactive
very highly branched so it can be hydrolysed extremely quickly to release glucose when nessacary

Question 23

how is cellulose adapted to it’s function?

Answer 23

it is long straight chains that form microfibrils
it is insoluble
it has hydrogen bonds between chains that provides tensile strength

Question 24

what are the monomers of lactose

Answer 24

lactose and glucose

Question 25

what are the monomers of sucrose

Answer 25

glucose and fructose

Question 26

what are the monomers of maltose

Answer 26

glucose and glucose

Question 27

name two features of a globular protein

Answer 27

soluble

hydrophillic

Question 28

name two features of a fibrous protein

Answer 28

insoluble

provide strength