A1.1 Water

First cell

Supposed to have evolved in oceans

Why water?

Water is a solvent that allows for complex biochemical reactions to occur

Aqueous solution

Any solution where water is the solvent: Cytoplasm, rivers and blood are all examples of this

Covalent Bond

When 2 atoms share electrons

Non polar covalent Bonds

electrons are negatively charged and nucleus is positively due to protons, so equally shared electrons create non polar covalent bonds

Because neither atom has higher electron density than the other

Polar Covalent Bonds

Covalent bonds between oxygen and hydrogen within water molecules because 1 oxygen electron bonds with 2 hydrogen electrons resulting in a slight negatively charged bond

Unequal sharing of electrons

Ephemeral attractions

Short lived attractions between water molecules and other charged atoms (ions)

Cohesion

When molecules of the same type are attracted to one another

Hydrogen Bonding

When slight positive and negative charges are attracted to one another. An ice crystal forms because of the slowing down of the molecules so that the bonding is frozen

Molecular Motion

Speed of molecules interacting = fast or slow, slow leads to ice crystals due to the freezing of bonds, fast leads to quicker interactions

Surface Tension

Caused by ephemeral hydrogen bonding

Lack of molecules above water surface leads to increasing cohesive force of around and below molecules

Tension

Pressure created by the cohesion of water molecules as evaporation occurs

Adhesion

Attraction of 2 unlike molecules due to hydrogen bonding

Hydrophilic

Dissolves easy in water

Loves water

Hydrophobic

Does NOT dissolve easily in water
Hates water

Enzymes

A dissolved proteins in cells that are biological catalysts

Require specific rates of life and temperatures tolerated by that type of cell

Catalyst

Substance that increases the rate of a chemical reaction without going through any permanent chemical change

Properties of Water

Buoyancy

Viscosity

Thermal Conductivity

Specific Heat Capacity