Biology Module 5 ~ The Chemistry of Life

Matter

Anything that has mass and takes up space

Model

An explanation or representation of something that cannot be seen

Element

A collection of atoms that all have the same number of protons

Molecules

Chemicals that result from atoms linking together

Physical Change

A change that affects the appearance but not the chemical makeup of a substance

Chemical Change

A change that alters the makeup of the elements or molecules of a substance

Phase

One of three forms — solid, liquid, or gas — which every substance is capable of attaining

Diffusion

The random motion of molecules from an area of high concentration to an area of low concentration

Concentration

A measurement of how much solute exists within a certain volume of solvent

Semipermeable Membrane

A membrane that allows some molecules to pass through but does not allow other molecules to pass through

Osmosis

The tendency of a solvent to travel across a semipermeable membrane into areas of higher solute concentration

Catalyst

A substance that alters the speed of a chemical reaction but is not used up in the process

Organic Molecule

A molecule that contains only carbon and any of the following: hydrogen, oxygen, nitrogen, sulfur, and/or phosphorous

Biosynthesis

The process by which living organisms produce larger molecules from smaller ones

Isomers

Two different molecules that have the same chemical formula but different structural formulas

Monosaccharides

Simple carbohydrates that contain 3 to 10 carbon atoms

Disaccharides

Carbohydrates that are made up of two monosaccharides linked together

Polysaccharides

Carbohydrates that are made up of more than two monosaccharides linked together

Dehydration Reaction

A chemical reaction in which molecules combine by removing water

Hydrolysis

Breaking down complex molecules by the chemical addition of water

Hydrophobic

Lacking any affinity to water

Saturated fat

A lipid made from fatty acids that have no double bonds between carbon atoms

Unsaturated fat

A lipid made from fatty acids that have at least one double bond between carbon atoms

Peptide bond

A bond that links amino acids together in a protein

Hydrogen bond

A strong attraction between hydrogen atoms and certain other atoms (usually oxygen or nitrogen) in specific molecules