Definitions 1

Question 1

Atom

Answer 1

The smallest component of an element. Made up of 3 different parts - electron, proton, neutron.

Question 2

Molecule

Answer 2

Consists of 3 or more atoms joined together with covalent bonds.

Question 3

Element

Answer 3

A chemical element is a substance that cannot be broken down any further by chemical means. Elements are defined by the number of protons they possess.

Question 4

Compound

Answer 4

Combination of 2 or more elements joined together chemically.

Question 5

Organic compound

Answer 5

Any of a large class of chemical compounds which contain carbon, except for the oxides e.g. carbon dioxide.

Question 6

Inorganic compound

Answer 6

Any substance in which 2 or more chemical elements other than carbon are combined e.g. water, sodium nitrate.

Question 7

Hydrogen bond

Answer 7

A relatively weak bond formed when partially positively charged groups come close to partially negative charged groups. e.g. water, secondary and tertiary structure proteins, between organic bases.

Question 8

Polarity

Answer 8

Uneven distribution of charges within a compound.

Question 9

Surface tension

Answer 9

The ‘skin’ on the surface of water formed as a result of hydrogen bonding in water molecules pulling the surface molecules downwards.

Question 10

Solvent

Answer 10

A liquid that dissolves solids (solutes).

Question 11

Metabolite

Answer 11

Any substance involved in metabolism (either as a product of metabolism or as necessary for metabolism).

Question 12

Monomer

Answer 12

The simplest, repeating unit bonded together to form a polymer.

Question 13

Polymer

Answer 13

A large molecule made up of many/repeating smaller molecules (monomers) covalently bonded together.

Question 14

Condensation

Answer 14

Chemical process in which two molecules bond covalently with elimination of water.

Question 15

Hydrolysis

Answer 15

The breaking down of large molecules into smaller molecules by the addition of water (digestion).

Question 16

Monosaccharide

Answer 16

Simple, single sugar molecule. The monomer of polysaccharides.

Question 17

Disaccharide

Answer 17

A molecule consisting of two monosaccharide sugars joined by a glycosydic bond.

Question 18

Polysaccharide

Answer 18

A polymer consisting of many monosaccharide sugars covalently bonded together.

Question 19

Triose sugar

Answer 19

A three carbon sugar.

Question 20

Pentose sugar

Answer 20

A five carbon sugar (e.g. deoxyribose and ribose sugar).

Question 21

Hexose sugar

Answer 21

A six carbon sugar (e.g. glucose)

Question 22

Structural Isomerism

Answer 22

Compounds that have the same chemical formula, but which differ in the arrangement of atoms.

Question 23

Reducing sugar

Answer 23

A sugar that will reduce Benedict’s solution (copper sulphate solution) thus changing it from blue to brick red)

Question 24

Non-reducing sugar

Answer 24

A sugar that will not reduce Benedict’s solution (copper sulphate solution) thus it remains blue.

Question 25

Benedict’s test

Answer 25

Add Benedict’s solution to a solution of sugar in a test tube and heat in a water bath at 100 degrees Celsius for 2 mins. Solution changes from blue to brick red.

Question 26

Iodine-potassium iodide test

Answer 26

Add iodine solution to starch. Colour change from brown/yellow to blue/black.