IB Biology Chapter 2: Molecular Biology Review

Polar covalent bonds

Unequal sharing of electrons in bonds between oxygen and hydrogen in a water molecule

Hydrogen bonds

Force that forms when a positive hydrogen atom in one polar molecule is attracted to the negative atom of another polar molecule

Cohesion

Molecules of the same type are attracted to each other; water molecules stick together

Surface tension

Effect of water molecules being more attracted to each other than to air particles, creating an elastic-like membrane on the surface of water

Adhesion

Attraction between two unlike molecules

Capillary action

Cohesion and adhesion work together to 'pull' up a column of water through a plant or narrow tube

Solution

Mixture of solvent (liquid, usually water) and solute (particle that is dissolved)

Solute

Particle that is dissolved

Solvent

Liquid, usually water

Hydrophilic

Water-loving; all substances that dissolve in water

Hydrophobic

Water-fearing; not attracted to water

Metabolism

Different chemical reactions using enzymes that take place in the cytoplasm of a cell

Buoyancy

Ability to float in fluid, water or air

Viscosity

Stickiness of a fluid which determines how easily it can flow, due to internal friction when parts of a fluid move relative to each other

Thermal conductivity

Rate at which heat passes through a material

Specific heat

Amount of heat required to raise the temperature of 1g of a substance by 1°C

Biochemistry

Branch of organic chemistry that attempts to explain the chemical characteristics of living organisms

Monomer

Small, simple molecules

Polymer

Repeated, linked units

Condensation reaction

Water molecules are produced when monomers are linked together to form larger molecules (polysaccharides, polypeptides, and nucleic acids)

Hydrolysis reaction

Reactions that require a water molecule to split apart a larger molecule into a smaller monomer

Glycoprotein

Polypeptides (proteins) with carbohydrate attached

Oligosaccharide

Carbohydrate with a short chain of monosaccharides linked by glycosidic bonds

Ester bond

Linkage formed between each fatty acid and the glycerol (bond between carboxyl group -COOH on fatty acid and -OH on glycerol)

Hydrogenation

Polyunsaturated fats are hydrogenated by removing or partly eliminating the double bonds by adding hydrogen atoms

Blubber

Thick adipose layer in marine mammals

Amphipathic

property of having hydrophilic and hydrophobic parts