2.1.2 biological molecules

Question 1

what is a monomer

Answer 1

a single repeating unit that can join with others to form polymers

Question 2

what is a condensation reaction

Answer 2

making a polymer out of monomers

Question 3

what is a hydrolysis reaction

Answer 3

breaking down polymers into monomers

Question 4

what type of molecule is water

Answer 4

a polar molecule (hydrogen is partially positive and oxygen is partially negative) with unevenly distributed charges

Question 5

what is cohesion

Answer 5

water molecules attracted to eachother

Question 6

what is adhesion

Answer 6

water molecules attracted to other molecules

Question 7

what is capillary action

Answer 7

adhesion and cohesion allow water to move up a capillary against gravity

Question 8

what are the properties of water

Answer 8

high boiling point (strong H bonds)
coolant - high specific heat capacity (lots of energy needed to raise temp by breaking H bonds)
ice is less dense
universal solvent
transport medium

Question 9

what do monosaccharides make and what type of reaction is it

Answer 9

polysaccharides with glycosidic bonds
condensation

Question 10

what is the difference between alpha glucose and beta glucose

Answer 10

alpha glucose has H above the OH on both sides
beta glucose has OH above the H on the right and the H above the OH on the left

Question 11

what are the hexose sugars

Answer 11

glucose
galactose
fructose

Question 12

what is the pentose sugar

Answer 12

ribose

Question 13

what are the triose sugars

Answer 13

aldose
ketose

Question 14

what is the disaccharide sucrose made of

Answer 14

B glucose + fructose

Question 15

what is the disaccharide lactose made of

Answer 15

galactose + A-glucose

Question 16

what is the disaccharide maltose made of

Answer 16

a glucose + a glucose

Question 17

what elements are carbohydrates made of

Answer 17

CHO

Question 18

what are the two types of starch

Answer 18

amylopectin and amylose

Question 19

describe amylopectin

Answer 19

a glucose
1-4 and 1-6 glycosidic bonds
branched

Question 20

describe amylose

Answer 20

a glucose
1-4 glycosidic bond
unbranched and coiled
soluble in water

Question 21

describe glycogen

Answer 21

a glucose
1-4 and 1-6 glycosidic bonds
very branched
compact
large surface area for release of glucose

Question 22

describe cellulose

Answer 22

b glucose (rotated 180° from eachother)
1-4 glycosidic bond
unbranched
many hydrogen bonds (strong)

Question 23

what elements are lipids made from

Answer 23

CHO

Question 23

what are lipids soluble in

Answer 23

organic substances only (e.g. alcohol)

Question 24

what is a saturated lipid

Answer 24

no carbon-carbon double bonds only found in animals

Question 25

what is an unsaturated lipid

Answer 25

contains carbon-carbon double bonds only found in plants weak intermolecular forces

Question 26

what is a triglyceride

Answer 26

1 glycerol + 3 saturated or unsaturated fatty acids joined by ester bonds energy reserves in plants and animals

Question 27

how are triglycerides different to phospholipids

Answer 27

1 fatty acid is replaced with a phosphate group

Question 28

what elements are proteins made from

Answer 28

CHON

Question 29

what are amino acids and what do they make

Answer 29

monomers that make proteins using peptide bonds

Question 30

what is an R group

Answer 30

a group in an amino acid specific to the protein

Question 31

what is a primary structure

Answer 31

order of amino acids in a protein

Question 32

what bonds are in the primary structure

Answer 32

peptide

Question 33

what is a secondary structure

Answer 33

shape taken by primary structure (either alpha helix or beta-pleated sheet)

Question 34

what bonds are in the secondary structure

Answer 34

peptide and hydrogen

Question 35

what is a tertiary structure

Answer 35

3D shape of protein

Question 36

what bonds are in the tertiary structure

Answer 36

peptide, hydrogen, disulphide and ionic

Question 37

what is a quarternary structure

Answer 37

how polypeptide chains fit to make a protein

Question 38

what are the properties of a globular protein

Answer 38

compact, spherical, soluble

Question 39

what is a conjugated protein

Answer 39

a protein containing a non-protein prosthetic group

Question 40

what are examples of globular proteins

Answer 40

insulin = regulates blood glucose levels (2 polypeptide chains joined by disulphide bonds) haemoglobin = transports O2 around the body as it binds to the haem group (4 polypeptide chains, 2 alpha, 2 beta)

Question 41

what are the properties of a fibrous protein

Answer 41

strong, insoluble, no tertiary structure

Question 42

what are the examples of fibrous proteins

Answer 42

collagen = connective tissue that provides support as it is flexible in low stress and stiff in high stress) keratin = strengthens hair and nails (more bonds means less flexible) elastin = walls of vessels

Question 43

what elements make up nucleotides

Answer 43

CHONP

Question 44

what do nucleotides make and what type of reaction is it

Answer 44

nucleic acids using phosphodiester bonds condensation

Question 45

what are the components of a nucleotide

Answer 45

phosphate group pentose deoxyribose sugar nitrogenous base

Question 46

what are the nitrogenous bases

Answer 46

adenine guanine thymine cytosine

Question 47

what do we use chromatography for

Answer 47

analysis of substances by separation

Question 48

how do we calculate the Rf value

Answer 48

distance moved by solute/distance moved by solvent

Question 49

what is colorimetry used for

Answer 49

concentration determination

Question 50

what do we use to test for starch and what is a positive result

Answer 50

iodine solution blue/black colour change

Question 51

what do we use to test for lipids and what is a positive result

Answer 51

ethanol emulsion - dissolve sample in ethanol and pour sample on top of distilled water cloudy emulsion

Question 52

what do we use to test for proteins and what is a positive result

Answer 52

biuret solution test blue to lilac colour change

Question 53

what do we use to test for reducing sugars and what is a positive result

Answer 53

benedicts reagent and heat for 5 mins at 80 degrees from blue to brick-red precipitate/green-red colour change

Question 54

what do we use to test for non-reducing sugars

Answer 54

after negative Benedict’s test acid hydrolysis using HCl and NaHCO3 powder - add hydrochloric acid and boil, cool then add alkali (sodium hydroxide) to neutralise add Benedict’s solution and heat for 5 mins at 80 degrees from blue to brick-red precipitate/green-red colour change

Question 56

How does the structure of starch lead to function

Answer 56

Helix can compact to fit a lot of glucose in a small space Branched structure of amylopectin increases SA for rapid hydrolysis back to glucose Insoluble so won’t affect water potential

Question 57

How does the structure of cellulose lead to function

Answer 57

Many H bonds provide collective strength Insoluble so won’t affect water potential

Question 58

How does structure of glycogen lead to function

Answer 58

Branched structure increases surface area for rapid hydrolysis back to glucose Insoluble so won’t affect water potential

Question 59

what kind of molecule is a lipid

Answer 59

Non-polar (no charge) so insoluble in water Hydrophobic