Chemistry of Living Things: Energy and Matter

Energy

Chemical energy from food or light energy used by plants for photosynthesis.

Thermal energy

Energy of moving atoms.

Temperature

Measurement of thermal energy in a substance.

Matter

Occupies space, has mass, and is made of particles.

Three states of matter

Solid, liquid, gas.

Brownian Motion

Random movement of particles in matter.

Diffusion

Process of particles mixing in liquids, gases, or solids.

Osmosis

Movement of water across a membrane.

Physical change in matter

No change in substance.

Chemical change in matter

Formation of a new substance.

Proton

Positively charged subatomic particle found in the nucleus with mass.

Neutron

Neutral subatomic particle found in the nucleus with mass.

Electron

Negatively charged subatomic particle with very small mass.

Isotope

Atom with a different number of neutrons.

Elements

Building blocks of all matter.

Periodic table

Arrangement of elements by number of protons.

Valence electrons

Electrons in the outer shell available for bonding.

Octet rule

Atoms are most stable with 8 electrons in the outer shell.

Chemical bond

Sharing of valence electrons between atoms.

Molecules

Two or more elements sharing electrons in a bond.

Law of Conservation of Mass

Mass is neither created nor destroyed in a chemical reaction.

Covalent Bond

Chemical bond where two atoms equally share a pair of electrons.

Ions

Formed when an atom loses or gains electrons.

Cation

Positively charged ion.

Anion

Negatively charged ion.

Ionic bonds

Formed by transfer of valence electrons between atoms.

Polar-covalent bond

Covalent bond with unequally shared electrons.

Metallic bonding

Equal sharing of electrons in a sea of atoms.

Compounds

Elements bonded together in a fixed ratio.

Solute

Solid substance in a solution.

Solvent

Liquid substance in which solutes dissolve.

Solution

Mixture of solute and solvent.

Organic compounds

Contain carbon and other elements like phosphorus, oxygen, sulfur, hydrogen, and nitrogen.

Carbohydrates

Organic molecules with carbon, hydrogen, and oxygen.

Lipids

Fats that dissolve in nonpolar solvents.

Saturated fats

Fats with no double bonds, liquid at room temperature.

Unsaturated fats

Fats with double bonds, solid at room temperature.

Trans-fats

Artificial unsaturated fats.

Acid

Donates H+ ions, pH below 7.

Base

Accepts H+ ions, pH above 7.

Amino acids

Building blocks of proteins, with amino, R, and acid groups.

Proteins

Chains of amino acids, building blocks of cells.

Enzymes

Proteins that act as catalysts in chemical reactions.

Catalyst

Speeds up reaction by lowering activation energy.

Denaturation

Change in protein shape, often due to heat.

Nucleic Acids

DNA and RNA storing information for protein synthesis.

Bases in DNA

Adenine (A) binds with Thymine (T), Cytosine (C) binds with Guanine (G).