Biological molecules

Question 1

Covalent bonds

Answer 1

Strong bonds formed when electrons are shared between atoms.

Question 2

Condensation reaction

Answer 2

A reaction that occurs when two molecules are joined together with the removal of water.

Question 3

Hydrolysis reaction

Answer 3

A reaction that occurs when a molecule is split into two smaller molecules with the addition of water.

Question 4

Monomer

Answer 4

A small molecule which bind to many other identical molecules to form a polymer.

Question 5

Polymer

Answer 5

A large molecule made from many smaller repeating units called monomers.

Question 6

Polar

Answer 6

When the charge is not evenly distributed across the particle.

Question 7

Polysaccharides

Answer 7

Polymers of monosaccharides that are made of many monosaccharide molecules bonded together.

Question 8

Phospholipid

Answer 8

A molecule consisting of glycerol, two fatty acids and one phosphate group.

Question 9

Peptide bond

Answer 9

A bond formed when two amino acids are joined together by a condensation reaction.

Question 10

Polypeptide

Answer 10

A polymer made of many amino acid units joined together by peptide bonds, e.g. insulin.

Question 11

Primary structure

Answer 11

The sequence of amino acids found in a protein molecule.

Question 12

a-glucose

Answer 12

Glucose in which the hydrogen atom on carbon 1 projects above the plane of the ring.

Question 13

Amylose

Answer 13

A molecule of polysaccharide with long straight chains of a-glucose molecules and glycosidic bonds between carbon 1 and 4. It is a constituent of starch.

Question 14

Amylopectin

Answer 14

A molecule of polysaccharide with glycosidic bonds between carbon 1 and 4, and branches formed by glycosidic bonds between carbon 1 and 6. It is a constituent of starch.

Question 15

Amino acids

Answer 15

Monomers of all proteins. All amino acids have the same basic structure.

Question 16

ab initio protein modelling

Answer 16

A model that is built based on the physical and electrical properties of the atoms in each amino acid in the sequence.

Question 17

B-glucose

Answer 17

Glucose in which the hydrogen atom on carbon 1 projects below the plane of the ring.

Question 18

Cohesion

Answer 18

The attraction between water molecules caused by hydrogen bonds.

Question 19

Carbohydrates

Answer 19

A group of molecules containing carbon, hydrogen and oxygen,

Question 20

Conjugated protein

Answer 20

A protein associated with a non protein component, e.g. haemoglobin.

Question 21

Comparative protein modelling

Answer 21

One approach is protein threading, which scams an amino acid sequence against a database of solved structures and produces a set of possible models which would match that sequence.

Question 22

Colorimeter

Answer 22

An instrument for measuring the absorbance of different wavelengths of light in a solution.

Question 23

Diasaccharide

Answer 23

Sugars where its molecules contain two monosaccharide residues joined by a condensation reaction.

Question 24

Disulfide links/bridges

Answer 24

Strong covalent bonds between two sulfur atoms within a protein molecule. These bonds are not broken by heat but can be broken by reducing agents.

Question 25

Ester bond

Answer 25

A bond formed formed by a condensation reaction between the -OH group of a carboxylic acid and the -OH group of an alcohol to produce an ester. This is the bond in lipids.

Question 26

Fibrous proteins

Answer 26

Proteins that have a long, thin structure, are insoluble in water and metabolically inactive. The often have a structural role within an organism.

Question 27

Glycosidic bond

Answer 27

A bond formed between two monosaccharides by a hydrolysis reaction.

Question 28

Glycogen

Answer 28

The energy store in humans. They are large polysaccharide molecules made of many glucose residues joined by condensation reactions. It has glycosidic bonds between carbon 1 and 4, and branches formed by glycosidic between carbon 1 and 6.

Question 29

Glycerol

Answer 29

A molecules with three carbon atoms. It is an alcohol so it has a free -OH group.

Question 30

Globular protein

Answer 30

A protein with a relatively spherical shape. They are soluble in water and often have metabolic roles within the organism.

Question 31

Hydrogen bond

Answer 31

A weak interaction that can occur wherever molecules contain a slightly negatively charged atom bonded to a slightly positively charged hydrogen atom.

Question 32

Hydrocarbon

Answer 32

A compound consisting of only hydrogen and carbon.

Question 33

Hydrophilic

Answer 33

Attracted to water.

Question 34

Hydrophobic

Answer 34

Repelled by water.

Question 35

Ionic bond

Answer 35

A type of chemical bond that involves the electrostatic attraction between oppositely charged ions.

Question 36

Lipid

Answer 36

A group of substances that are soluble in alcohol rather than water.

Question 37

Fatty acids

Answer 37

They have a carboxyl group (-COOH) on one end, attached to a hydrocarbon tail. They make up some lipids (triglycerides and phospholipids).

Question 38

Monosaccharides

Answer 38

Sugars that cannot be hydrolysed to give a simpler sugar. The monomer of polysaccharides.

Question 39

Macromolecules

Answer 39

A very large, organic molecule.

Question 40

Quaternary structure

Answer 40

Protein structure where a protein consists of more than one polypeptide chain.

Question 41

Secondary structure

Answer 41

The coiling or folding of an amino chain, which arises often as a result of hydrogen bond formation between different parts of the chain.

Question 42

Tertiary structure

Answer 42

The overall three-dimensional shape of a protein molecule. Its shape arises due to interactions including hydrogen bonds, disulfide bridges, hydrophobic interactions and ionic bonds.

Question 43

Respiration

Answer 43

A process in living organisms involving the release of energy from food. It involves the oxidation of complex organic substances, such as glucose or fatty acids.

Question 44

Solvent

Answer 44

A substance capable of dissolving other substances (solutes).

Question 45

Solute

Answer 45

A substance that can be dissolved in a solvent.

Question 46

Specific heat capacity

Answer 46

The amount of thermal energy required to raise 1kg of that substance by 1℃.

Question 47

Latent heat of vaporisation

Answer 47

The amount of energy needed to change 1kg of a liquid substance to a gas.

Question 48

Triglyceride

Answer 48

A type of lipid (commonly known as fat) made up of a glycerol molecule and three fatty acids.

Question 49

Reducing sugar

Answer 49

A sugar that can donate electrons. When a reducing sugar is placed in benedict's reagent, it donates an electron to the Cu2+, turning it into Cu+, and this is what changes the colour from blue to brick red. Examples of reducing sugars include glucose, fructose, and maltose.

Question 50

Non reducing sugar

Answer 50

A sugar that cannot donate electrons. The sugar must first be hydrolysed to break the disaccharide into two monosaccharides before a benedict's test can be caried out. An example of a non reducing sugars is sucrose.