BIOL 2100 CH. 2 NOTES

Matter

Anything that occupies space and possesses mass, including solids, liquids, gases, and living organisms.

Elements

Fundamental building blocks of matter that cannot be decomposed into simpler substances; represented on the periodic table.

Compounds

Substances formed from the chemical combination of two or more different elements in a specific ratio, exhibiting distinct properties.

Emergent Properties

Characteristics of compounds that are not present in the individual elements that compose them.

Essential Elements

Elements necessary for organisms to live healthily and reproduce; vary in quantity among different organisms.

Major Elements in Living Matter

Key elements such as Oxygen (O), Carbon (C), Hydrogen (H), and Nitrogen (N) that make up approximately 96.3% of body mass.

Trace Elements

Elements required in minute quantities (less than 0.01% of body mass), such as Iron (Fe) and Iodine (I).

Atoms

The smallest units of matter that retain the unique properties of their respective elements, composed of subatomic particles.

Subatomic Particles

Protons (positively charged), Neutrons (neutral), and Electrons (negatively charged) that make up an atom.

Atomic Number

The number of protons in an atom's nucleus, which uniquely defines the element.

Chemical Bonds

Interactions that hold atoms together in molecules and compounds, including covalent and ionic bonds.

Covalent Bonds

Bonds formed by the sharing of electron pairs between atoms.

Ionic Bonds

Bonds formed through the transfer of electrons, resulting in oppositely charged ions.

Chemical Reactions

Processes that make and break chemical bonds, altering the composition of matter.

Reactants

Starting materials in a chemical reaction.

Products

Resulting materials in a chemical reaction.

Photosynthesis

A biological process where plants convert CO₂ and H₂O into glucose and O₂ using sunlight.

Dynamic Equilibrium

A state in which the rate of the forward reaction equals the rate of the reverse reaction, maintaining stable concentrations.

Polar Molecule

A molecule with an uneven charge distribution, such as water, which has a partial negative charge on oxygen and partial positive charges on hydrogen.

Hydrogen Bonding

Attraction between partially positive hydrogen atoms of one water molecule and partially negative oxygen atoms of neighboring water molecules.

Cohesion

The tendency of water molecules to stick together due to hydrogen bonding, contributing to surface tension.

High Specific Heat

Water's ability to absorb and release large amounts of heat with minimal temperature change, stabilizing environments for life.

Density of Ice

Ice is less dense than liquid water due to its crystalline structure, allowing it to float and insulate aquatic life.

Acids

Substances that increase the concentration of hydrogen ions (H⁺) in a solution.

Bases

Substances that decrease the concentration of hydrogen ions in a solution.