Unit 1: Chemistry of Life (copy)

Elements

Substances that cannot be broken down into simpler substances by chemical means.

Trace elements

Elements required by an organism in very small quantities.

Protons

Positively charged particles found in the nucleus of an atom.

Neutrons

Uncharged particles found in the nucleus of an atom.

Electrons

Negatively charged particles found outside the nucleus of an atom.

Isotopes

Atoms with the same number of protons but different number of neutrons in the nucleus.

Compounds

Consist of two or more elements held together by chemical bonds.

Ionic bond

Formed when one or more electrons are transferred from one atom to another.

Covalent bond

Formed when electrons are shared between atoms.

Hydrogen bond

Weak chemical bond formed between a hydrogen atom and another atom.

Cohesion

The tendency of water molecules to stick together.

Adhesion

The tendency of water molecules to stick to other substances.

Capillary action

The ability of water to rise up the roots, trunks, and branches of trees.

Surface tension

The cohesive forces that create a "skin" on the surface of water.

Acids

Solutions that contain a lot of hydrogen ions (H+).

Bases

Solutions that release a lot of hydroxide ions (OH–).

pH scale

A scale used to measure the acidity or alkalinity of a solution.

Organic molecules

Molecules that contain carbon atoms.

Inorganic compounds

Molecules that do not contain carbon atoms.

Polymers

Chains of building blocks in macromolecules.

Monomers

The individual building blocks of a polymer.

Dehydration synthesis

A reaction in which a water molecule is lost and a larger compound is formed.

Hydrolysis

A reaction in which polymers are broken down into monomers with the addition of water.

Carbohydrates

Organic compounds that contain carbon, hydrogen, and oxygen in a ratio of approximately 1:2:1.

Monosaccharides

Simple sugars that serve as an energy source for cells.

Disaccharides

Sugars formed by the joining of two monosaccharides.

Polysaccharides

Complex carbohydrates made up of many repeated units of monosaccharides.

Proteins

Important for structure, function, and regulation of tissues and organs.

Amino acids

Building blocks of proteins.

Polypeptides

Chains of amino acids joined by peptide bonds.

Primary structure

The linear sequence of amino acids in a protein.

Secondary structure

The folding of a polypeptide into alpha helices or beta-pleated sheets.

Tertiary structure

The overall 3D shape of a protein.

Quaternary structure

The interaction of multiple polypeptide chains to form a functional protein.

Lipids

Organic compounds that consist of carbon, hydrogen, and oxygen atoms.

Triglycerides

Lipids made of a glycerol molecule and three fatty acid chains.

Saturated fatty acids

Fatty acids with no double bonds in the carbon chain.

Unsaturated fatty acids

Fatty acids with one or more double bonds in the carbon chain.

Phospholipids

Lipids with two fatty acid tails and a phosphate head.

Cholesterol

A four-ringed molecule found in membranes.

Nucleic acids

Molecules made up of nucleotides, containing genetic information.