biological molecules

Question 1

describe the structure of a water molecule

Answer 1

oxygen atom covalently bonded to 2 hydrogen atoms. It is a non-linear shape

Question 2

what bond can link two water molecules together

Answer 2

hydrogen bond

Question 3

what is a hydrogen bond

Answer 3

a weak interaction that can occur whenver moleucles contain a slightly negatively charged atom bonded to a slightly positively charged hydrogen

Question 4

where does hydrogen bonds occur between water molecules

Answer 4

between a hydrogen on one molecules and the oxygen of another molecule

Question 5

define polar

Answer 5

has 2 poles - one slightly positive, other slightly negative

Question 6

why is water a polar molecule

Answer 6

electrons are more attracted to the oxygen atom so is pulled towards it, causing the O to be slightly negative and the Hs to be slightly positive

Question 7

define electronegativity

Answer 7

measure of the tendency of an atom to attract a bonding pair of electrons

Question 7

define electronegativity

Answer 7

measure of the tendency of an atom to attract a bonding pair of electrons

Question 8

define dipole

Answer 8

a molecule in which a concentration of positive electric charge is separated from a concentration of negative charge

Question 9

list roles water plays in life

Answer 9

solvent, transport medium, habitat, reactant, thermal stability, solvent

Question 10

why is water a useful solvent

Answer 10

polar and charged molecules interact with polar water molecules - cluster around them which keeps them apart

Question 11

why is water a useful transport medium

Answer 11

water stays a liquid over a large temperature range - H bonds require lots of energy to break.

Question 12

why is water a useful coolant

Answer 12

high specific heat capacity - H bonds require lots of energy to break

Question 13

why is water a useful habitat

Answer 13

maintains a constant temp.

Question 14

why is water a useful habitat

Answer 14

maintains a constant temperature due to energy required to break H bonds

Question 15

define hydrophilic

Answer 15

property of a molecule that is attracted to water

Question 16

define hydrophobic

Answer 16

property of a molecule that is repelled by water

Question 17

define cohesion

Answer 17

water molecules attracted to one another

Question 18

define adhesion

Answer 18

water molecules attracted to other substances

Question 19

how is water being transparent to light make it useful for life

Answer 19

plants growing under water can get light for photosynthesis and aquatic animals can see underwater

Question 20

explain how water can dome above the level of the container it is in

Answer 20

cohesion between water molecules causing surface tension due to hydrogen bonds

Question 21

explain how water can form a meniscus in a measuring cyclinder

Answer 21

adhesion to sides of container draws molecules up

Question 22

explain capillary action of water in a narrow tube

Answer 22

cohesion between water molecules and adhesion to other molecules causes water to move up narrow spaces

Question 23

define monomer

Answer 23

individual molecules that make up a polymer

Question 24

define polymer

Answer 24

long-chain molecules compsed of multiple individual molecules (monomers) in a repeating pattern

Question 25

define macromolecule

Answer 25

large complex molecules with large molecular masses

Question 26

define dimer

Answer 26

a molecule consisting of two identical molecules linked together

Question 27

define oligomer

Answer 27

a polymer whose molecules consist of relatively few repeating units

Question 28

define condensation reaction

Answer 28

reaction between two molecules to form a bigger one, releases a water molecule

Question 29

define hydrolysis reaction

Answer 29

the breakdown of a molecule into two smaller molecules requiring the addition of a water molecule

Question 30

define metabolism

Answer 30

chemical processes in a living organism in order to maintain life

Question 31

define catabolic reaction

Answer 31

reactions of metabolism that break molecules into smaller units. release energy

Question 32

define anabolic reaction

Answer 32

reactions of metabolism that construct molecules from smaller units - require energy from hydrolysis of ATP

Question 33

4 main categories of biological molecule

Answer 33

carbohydrates lipids proteins nucleic acids

Question 34

what is a single bond

Answer 34

chemical bond which one pair of electron is shared between two atoms

Question 35

define double bond

Answer 35

chemical bond that shares two pairs of electrons between two atoms

Question 36

what elements are present in carbohydrates

Answer 36

carbon, hydrogen, oxygen

Question 37

general formula of carbohydrates

Answer 37

(CH2O)n

Question 38

define monosaccharide

Answer 38

a single sugar molecule

Question 39

define disaccharide

Answer 39

a molecule comprised of two monosaccharides joined by a glycosidic bond

Question 40

define polysaccharide

Answer 40

a polymer made of many sugar monomers

Question 41

define pentose sugar

Answer 41

a monosaccharide composed of 5 carbons

Question 42

define hexose sugar

Answer 42

a monosaccharide composed of 6 carbons

Question 43

define triose sugar and give an example

Answer 43

monosaccharide composed of 3 carbons e.g. glyceraldehyde

Question 44

define furanose ring

Answer 44

5 membered ring e.g. fructose

Question 45

define pyranose ring

Answer 45

a 6-membered ring e.g. glucose

Question 46

define isomer

Answer 46

molecules with same atoms but arranged differently

Question 47

what is the difference between alpha and beta glucose

Answer 47

the hydrogen and hydroxyl groups on carbon 1 are reversed

Question 48

what are the differences between alpha glucose and ribose

Answer 48

glucose is pyranose, ribose is furanose glucose used in starch and glycogen ribose used in RNA

Question 49

which monosaccharides make up sucrose

Answer 49

alpha glucose and fructose

Question 50

which monosaccharides make up maltose

Answer 50

two alpha glucose

Question 51

which monosaccharides make lactose

Answer 51

alpha glucose and galactose

Question 52

how do two glucose molecules form a disaccharide

Answer 52

condensention reaction on carbons 1 and 4, between hydroxyl groups water is lost, bond is formed by remaining oxygen atom

Question 53

what is the reaction that breaks glycosidic bonds

Answer 53

hydrolysis - breaking the bond by the addition of water

Question 54

why does alpha glucose form starch and beta glucose form cellulose

Answer 54

due to the arrangement of the H/OH on carbon 1. 1-4 glycosidic bonds in alpha glucose mean they can bond all facing the same way up but beta needs need to flip 180 degrees every time.

Question 55

which polysaccharides make up starch

Answer 55

amylose (1-4 bonds only) and amylopectin (both 1-4 and 1-6)

Question 56

why are glycosidic bonds 1-4, 1-6

Answer 56

describes the bonds between the OH group on either carbon 1-4 or 1-6

Question 57

describe the structure of cellulose fibre

Answer 57

several cellulose molecules = microfibril several microfibrils = macrofibril macrofibrils laid down in layers to form cell wall

Question 58

what are the properties and functions of starch

Answer 58

coils into helix amylase unbranched, amylopectin branched compact and insoluble - ideal for storage, food store in plants

Question 59

properties and functions of glycogen

Answer 59

more branched than amylopectin coils into helix compact and insoluble - ideal for storage in animals and fungi

Question 60

properties and functions of cellulose