BIOCHEMISTRY NOTES FOR STANDARD LEVEL

Powerpoint Presentation: Biochemistry

Recommended units and SI units

• Distance (m); mass (kg); time (s, min, h, day, month or a);
• temperature (°C, rarely K in biology);
• volume (cm³ or dm³ );
• amount of substance (mol); force (N); pressure (Pa or atmospheres or mm Hg); potential difference (v); energy (J or cal); power (work) (W); illumination (lx)

Chemical terms to know

• atom – the smallest part of an element
• molecule – the smallest particle of a substance which can exist in a free state (e.g. O₂).
• compound – a molecule or particle made of different elements (e.g. H₂O)
• element – a type of atom, a substance which cannot be further divided by chemical methods e.g. oxygen
• electromagnetic spectrum – waves of energy (e.g. light rays, UV & infra red radiation)
• electron (e^-), proton (H⁺), ion (a charged particle), cation (a positively charged particle e.g. Na⁺ or Ca²⁺), anion (a negatively charged particle e.g. Cl^- or NO₃^-),
• solution = solute(substance: solid, liquid or gas) + solvent (liquid).
• hydrophobic – repelled by water, hydrophilic – attracted to water.
• suspension – very small solid particles dispersed in a liquid.
• sediment – solid particles which settle to the bottom of a liquid.
• precipitate – a solid produced from a reaction in a solution.
• diffusion – the movement of molecules from an area of high concentration to an area of low concentration.
• dialysis – selective diffusion of particles through a partially permeable membrane.
• osmosis – the movement of water across a partially permeable membrane from a region of high solute concentration to a region of low solute concentration.
• covalent bond – a strong bond formed by the sharing of electrons between two atoms e.g. the peptide bond between amino acids.
• hydrogen bonding – a weak bond between hydrogen and a negative element e.g. between hydrogens and oxygens of different water molecules,
• hydrolysis – the breaking of a covalent bond between two organic molecules using water (NB not dissolving in water)
• condensation – the formation of a strong covalent bond between two organic molecules releasing water.

• H, O, C, are the most common.
• N, S, P are also important as well as the metals Na, Ca, and Fe.
• H, O, C, N, S and P form covalent bonds (single, double or triple
  e.g. –C-C–, –C=O, –CN).
• H, O, C, N, S and P are light.
• H, O, C, N, S and P very reactive.
• H, O, C, N, S and P produce diverse compounds which are reduced (readily oxidised).

CARBON

Tetravalent 4 different bonds variety isomerism.

Forms long chains (polymers) macromolecules and ring structures.

Tetrahedral structure 3 D variation optical isomerism.

Organic compounds

• Compounds containing carbon found in living organisms.
• Not including carbonates, hydrogen carbonates, CO₂ or CO.
• Often based upon a skeleton of carbon.
• An infinite variety possible.
• Evolution has chosen a few for use in living organisms.
• There are four principal groups: sugars, fatty acids, amino acids and nucleotides

• Carbohydrates
• Lipids
• Amino acids and proteins
• Topic Chapters Index
• Top of Page

© Paul Billiet 2012