SQA Higher Chemistry Area 2 Nature's Chemistry overview quiz quiz

Condensation, with a water molecule lost

Hydrolysis, with a water molecule added to break the bond

Oxidation, with oxygen being added to the molecule

Reduction, with hydrogen being added to the molecule

Amino acids

Fatty acids

Simple sugars

Alcohols only

Oils are made up of much smaller molecules than the molecules found in solid fats

Oils contain no ester links at all, whereas the solid fats are firmly held together by many ester links

Oils are more unsaturated, so the chains cannot pack closely and the intermolecular forces are weaker

Fats are ionic compounds, while oils are simple covalent molecular substances

The ester link, as found in fats and oils

A hydrogen bond between the amino acids

An ionic bond between charged groups

The peptide (amide) link

It is denatured, changing its three-dimensional shape so it no longer works

It speeds up permanently and then works much faster for the rest of the reaction

It turns completely into a single free amino acid molecule

Nothing changes at all and the enzyme keeps working as before

Both the aldehyde and the ketone decolourise bromine water quickly

A mild oxidising agent oxidises the aldehyde but not the ketone

The ketone turns blue litmus paper red, but the aldehyde does not

Only the ketone dissolves in water, while the aldehyde is insoluble

In the middle of the carbon chain

On a side branch only

At the end of the carbon chain

Aldehydes do not contain a carbonyl group

Water hydrolyses the ester links and splits the whole molecule apart into pieces

The glycerol part of the molecule slowly evaporates away over time

Bacteria steadily add hydrogen atoms to the fatty acid molecules

Oxygen attacks the carbon-to-carbon double bonds of the unsaturated chains

It is oxidised in preference to the food, losing electrons itself

It forms a barrier that blocks all of the oxygen from reaching the food

It cools the food right down so the oxidation reaction cannot happen

It hydrolyses the fat molecules before they have a chance to oxidise

Two hydrophilic ionic heads, one at each end of the molecule

A hydrophilic ionic head and a hydrophobic hydrocarbon tail

Two long hydrophobic hydrocarbon tails and no ionic head at all

A positive and a negative charge at each end, but no tail at all

Amino acid units

Glucose units

Isoprene units

Ester units

It reflects all of the incoming UV light away from the surface of the skin completely

It cools the skin down so that the UV light can no longer cause any harm to it

It thickens the outer layer of the skin so the UV light cannot get through it at all

It reacts with free radicals and removes them, stopping the damaging chain reactions