Biological Molecules

Question 1

Covalent Bond

Answer 1

Type of chemical bond in which two atoms share a pair of electrons.

Question 2

Chemical bond formed between the positive charge on a hydrogen atom and the negative charge on another atom of an adjacent molecule e.g. between the Hydrogen atom of one water molecule and the Oxygen atom of an adjacent water molecule

Answer 2

Hydrogen Bond

Question 3

Ionic Bond

Answer 3

A bond between a positive ion which has lost an electron(s) and a negative ion which has gained an electron(s).

Question 4

A molecule which has a partially positive charge in one part of the molecule and completely negative charge in another part (a dipole).

Answer 4

Polar Molecule

Question 5

One of many small molecules that combine together to form a polymer

Answer 5

Monomer

Question 6

The process of making a polymer

Answer 6

Polymerisation

Question 7

Chemical process in which two molecules combine to form a more complex one with the elimination of a simple substance, usually water. Many biological polymers (e.g. polysaccharides, polypeptides) are formed by condensation.

Answer 7

Condensation

Question 8

The breaking down of large molecules into smaller ones by the addition of water molecules.

Answer 8

Hydrolysis

Question 9

All the chemical processes that take place in living organisms.

Answer 9

Metabolism

Question 10

Mole

Answer 10

The mass of a substance containing the same number of fundamental units as there are atoms in exactly 12g of 12C.

Question 11

An aqueous solution that contains 1 mole of solute in 1 litre of solution.

Answer 11

Molar (M) Solution

Question 12

Compounds made from carbon, hydrogen and oxygen. Either monosaccharides, disaccharides and polysaccharides.

Answer 12

Carbohydrate

Question 13

A single sugar e.g. glucose

Answer 13

Monosaccharide

Question 14

Large molecule made up of many repeating smaller molecules (monomers).

Answer 14

Polymer

Question 15

Made up of two sugar units that are formed by a condensation reaction. Monosaccharides are joined by a glycosidic bond.

Answer 15

Disaccharide

Question 16

Organic Molecule

Answer 16

Molecules containing carbon that can be found in living things; four classes are carbohydrates, proteins (chain of amino acids), lipids, and nucleic acids

Question 17

Made of many sugar units that are formed by a condensation reaction. Monosaccharides are joined by a glycosidic bond.

Answer 17

Polysaccharide

Question 18

A sugar made up of 6 carbons.

Answer 18

Hexose sugar

Question 19

C6H12O6 – a single sugar which is used in respiration.

Answer 19

Glucose

Question 20

A sugar that serves as a reducing agent. All monosaccharides are reducing sugars along with some disaccharides.

Answer 20

Reducing Sugar

Question 21

Reducing sugar test

Answer 21

Heat solution with Benedict’s reagent to test for reducing sugars. If it goes brick red then a reducing sugar is present.

Question 22

Blue solution which is used to test for reducing and non-reducing sugars.

Answer 22

Benedict’s reagent

Question 23

Glycosidic bond

Answer 23

Bond between sugar molecules in disaccharides and polysaccharides.

Question 24

A sugar which cannot serve as a reducing agent. An example is sucrose.

Answer 24

Non-reducing sugar

Question 25

Non-reducing sugar test

Answer 25

Following a negative reducing sugars test. Heat the solution with HCl to hydrolyse the non-reducing sugar into it’s monosaccharides. Then perform the Benedict’s test again. If you get a positive result after hydrolysis then a non-reducing sugar is present.

Question 26

Starch

Answer 26

A polysaccharide found in plant cells made up of alpha-glucose – comprised of amylose (alpha-1,4 glyosidic bonds) and amylopectin (alpha-1,4- and alpha-1,6-glyosidic bonds).

Question 27

A highly branched polysaccharide made up of alpha-glucose found in animal cells (alpha-1,4- and alpha-1,6-glyosidic bonds).

Answer 27

Glycogen

Question 28

Cellulose

Answer 28

A polysaccharide made up of beta-glucose found in plant cells (beta-1,4-glycosidic bonds).

Question 29

An isomer of glucose that can bond together to form starch or glycogen.

Answer 29

Alpha glucose

Question 30

Beta glucose

Answer 30

An isomer of glucose that **can bond together** to form cellulose.

Question 31

Lipid

Answer 31

A class of organic compounds that are fatty acids are their derivatives and are insoluble in water but soluble in organic solvents. They include triglycerides, phospholipids, waxes and steroids.

Question 32

An individual lipid molecule made up of a glycerol molecule and three fatty acids. Contains ester bonds.

Answer 32

Triglyceride

Question 33

A carboxylic acid with a hydrocarbon tail.

Answer 33

Fatty acid

Question 34

A molecule which combines with three fatty acids to form triglycerides. It is 3 carbon chain with 3 hydroxyl groups.

Answer 34

Glycerol

Question 35

A fatty acid in which there are no double bonds between the carbon atoms

Answer 35

Saturated fatty acid

Question 36

Mono-unsaturated fatty acid

Answer 36

Fatty acid which possesses a carbon chain with a single double bond between carbon atoms.

Question 37

Fatty acid which possesses a carbon chain with many double bonds between carbon atoms.

Answer 37

Poly-unsaturated fatty acid

Question 38

Triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule. Phospholipids are important in the structure an functioning of plasma membranes.

Answer 38

Phospholipid

Question 39

Section of a molecule which is attracted to water.

Answer 39

Hydrophilic

Question 40

Section of a molecule which is repulsed by water.

Answer 40

Hydrophobic

Question 41

Emulsion test

Answer 41

Test for lipids. Mix your sample with ethanol and then add water. If a white cloudy emulsion forms then a lipid is present.

Question 42

Protein

Answer 42

A polymer which is made up of amino acids linked by peptide bonds. May also contain prosthetic groups as part of its quaternary structure.

Question 43

A monomer which makes up proteins. Has a central carbon atom which is bonded to: a carboxylic acid group, an amino group, a hydrogen atom and a R group.

Answer 43

Amino acid

Question 44

Amino group

Answer 44

The -NH2 group of an amino acid.

Question 45

Carboxyl group

Answer 45

The -COOH group of an amino acid.

Question 46

R-group

Answer 46

Each of the 20 amino acids has a different R group – determines the bonding that the amino acid can carry out.

Question 47

The type of bond that is formed between two amino acids.

Answer 47

Peptide bond

Question 48

Many amino acids joined together by peptide bonds.

Answer 48

Polypeptide

Question 49

The sequence of amino acids that makes up the polypeptides of a protein.

Answer 49

Primary protein structure

Question 50

Secondary protein structure

Answer 50

The way in which the chain of amino acids of the polypeptides of a protein is folded.

Question 51

Tertiary protein structure

Answer 51

The folding of a whole polypeptide chain in a precise way, as determined by the amino acids of which it is composed.

Question 52

Bond formed between Sulphur atoms in R groups of amino acids.

Answer 52

Disulfide bridge

Question 53

Quaternary protein structure

Answer 53

A number of polypeptide chains linked together, and sometimes associated with non-protein groups to form a protein.

Question 54

A simple biochemical reaction to detect the presence of protein, if the Biuret’s solution turns purple then protein is present.

Answer 54

Biuret test