While both prokaryotes and some eukaryotes can be unicellular, the term 'prokaryote' specifically refers to simple, single-celled organisms that lack a membrane-bound nucleus. This group includes bacteria and archaea, which are the most ancient and widespread forms of life on Earth.

A neutron is a subatomic particle found in the nucleus of an atom alongside protons. Unlike protons, which carry a positive charge, and electrons, which carry a negative charge, neutrons possess no net electrical charge, making them electrically neutral. This neutrality is essential for the stability of the atomic nucleus, as it helps mitigate the electrostatic repulsion between positively charged protons.

Electrons are subatomic particles that carry a fundamental negative electric charge. They orbit the nucleus of an atom and play a critical role in chemical bonding and electricity. In contrast, protons carry a positive charge, and neutrons are electrically neutral.

Eukaryotic cells are defined by the presence of a membrane-bound nucleus that houses genetic material, along with various membrane-bound organelles such as mitochondria and the endoplasmic reticulum. In contrast, prokaryotic cells lack a true nucleus and membrane-bound organelles. The cytoplasm and cell membrane are fundamental components shared by both, but the organized compartmentalization is a hallmark of eukaryotes.

The nucleus is the small, dense central region of an atom consisting of protons and neutrons. It contains the vast majority of the atom's mass, while electrons orbit this central core in shells or clouds.

An atom is the smallest unit of ordinary matter that forms a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons. The number of protons in the nucleus defines the identity of the element, making the atom the basic building block of all chemical substances.

The cell theory states that the cell is the basic unit of life. All living organisms are composed of one or more cells, and all metabolic processes, including energy production and reproduction, occur within this fundamental unit.

The cell wall is a rigid, protective layer located outside the plasma membrane of plant cells. It is primarily composed of cellulose, hemicellulose, and pectin. The cell wall provides structural support, maintains cell shape, and prevents excessive water uptake, which is crucial for the plant's ability to stand upright and withstand osmotic pressure.

A polar covalent bond occurs when electrons are shared unequally between two atoms due to differences in electronegativity. This creates a partial positive charge on one atom and a partial negative charge on the other, resulting in a dipole moment.

Radioisotopes are isotopes of an element that have an unstable nucleus. Because of this instability, they spontaneously decay, releasing energy in the form of radiation (such as alpha, beta, or gamma particles) until they reach a more stable state.