Basic Chemistry & Atomic Structure

Essential elements

Four essential elements of life: Oxygen, Carbon, Hydrogen, Nitrogen (CHN).

Subatomic particles

Protons (positive charge), neutrons (no charge), and electrons (negative charge) that make up atoms.

Atomic number

The number of protons in an atom, which defines the element.

Mass number

The total number of protons and neutrons in the nucleus of an atom.

Isotopes

Atoms of the same element that have different mass numbers due to differing numbers of neutrons.

Radioactive isotopes

Isotopes that are unstable and decay, releasing energy and particles.

Electron distribution

The arrangement of electrons in various shells around an atom's nucleus.

Valence electrons

Electrons in the outermost shell of an atom that determine its reactivity.

Chemical bond

An attraction between atoms that allows them to form molecules and compounds.

Orbital

The 3D space around a nucleus where an electron is likely to be found.

The basic unit of life is the _____ .

cell

All living organisms are made up of _____ .

cells

The control center of a cell is the _____.

nucleus

_____ is the process by which cells obtain energy from glucose.

cellular respiration

In a chemical reaction, the substances that undergo change are called _____.

reactants

The region in which an enzyme binds to its substrate is known as the _____.

active site

_____ are biological catalysts that speed up chemical reactions in cells.

Enzymes

Photosynthesis takes place in the _____.

chloroplasts

The molecules produced by the end of cellular respiration are _____.

ATP, carbon dioxide, and water

The semi-permeable structure that surrounds a cell is called the _____.

cell membrane