Week 1 - Chemistry For Biologists

Atom

Nucleus = protons (+ve) + neutrons (no charge), electrons (-ve) in cloud around this.

Isotopes

Same number of protons (therefore same element) but different number of neutrons.

Atom

Nucleus = protons (+ve) + neutrons (no charge), electrons (-ve) in cloud around this.

Isotopes

Same number of protons (therefore same element) but different number of neutrons.

Radioactive isotopes

Some isotopes are not stable.

Molecules

Contain two or more elements joined together eg molecular oxygen O2.

Compounds

Molecules made up of different elements eg carbon dioxide CO2.

Covalent bond

Electrons are shared (Two non-metals eg. H2O).

Ionic bond

Not shared evenly (between non-metal and metal eg. NaCl).

Metallic bond

Electrons shared (Two metals).

Hydrogen bonds

A special type of dipole dipole bond occurs specifically between a hydrogen atom bonded to either an oxygen, nitrogen, or fluorine atom.

Dipole dipole bonds

Occur when the partially positively charged part of a molecule interacts with the partially negatively charged part of the neighbouring molecule.

Van der Waal's forces

Also called London dispersion forces; weak in small molecules, but increase in strength in larger molecules.

Organic compounds

Compounds built around carbon which likes to form 4 covalent bonds.

Inorganic compounds

Compounds that do not contain C-H bonds.

Structure = function

The three-dimensional shape of macromolecules is due to the covalent bonds formed by carbon.

Temporary dipole effect

Occurs when electrons collect asymmetrically around the molecule.

Polar covalent bonds

Bonds where there is a difference in electronegativity between the atoms involved, leading to partial charges.

Hydrogen bonds in DNA

Hydrogen bonds between the nitrogenous bases in DNA.

Macromolecules

Large molecules that include proteins, lipids, carbohydrates, and double stranded DNA.

Electronegativity

The tendency of an atom to attract electrons towards itself.

Nucleus

The central part of an atom, containing protons and neutrons.

Electrons

Negatively charged particles that orbit the nucleus of an atom.

Protons

Positively charged particles found in the nucleus of an atom.

Neutrons

Neutral particles found in the nucleus of an atom.

Chemical bonds

Forces that hold atoms together in compounds and molecules.