In biology, cell theory is the historic scientific theory, now universally accepted, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells.

The nucleus is an organelle found in eukaryotic cells. Inside its fully enclosed nuclear membrane, it contains the majority of the cell's genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes.

deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.

the fundamental and distinctive characteristics or qualities of someone or something, especially when regarded as unchangeable.

any of a number of organized or specialized structures within a living cell.

Bacteria (singular: bacterium) are classified as prokaryotes, which are single-celled organisms with a simple internal structure that lacks a nucleus, and contains DNA that either floats freely in a twisted, thread-like mass called the nucleoid, or in separate, circular pieces called plasmids.

Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane. It is mainly composed of water, salts, and proteins. ... All of the organelles in eukaryotic cells, such as the nucleus, endoplasmic reticulum, and mitochondria, are located in the cytoplasm.

the outer layer of the membrane surrounding the cytoplasm of a cell.

a rigid layer of membrane lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants it consists mainly of cellulose.

(in green plant cells) a plastid that contains chlorophyll and in which photosynthesis takes place.

an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur. It has a double membrane, the inner layer being folded inward to form layers

a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid.

the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.

cellular respiration is when cells release energy from the chemical bonds of food molecules and provide that energy for the essential processes of life.

It can be aerobic respiration in the presence of oxygen or anaerobic respiration.

a particle consisting of RNA and associated proteins found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins.

Animal cells are the basic unit of life in organisms of the animal kingdom. They are eukaryotic cells, meaning that they have a true nucleus and specialized structures called organelles that carry out different functions.

Plant cells are the basic unit of life in organisms of the plant kingdom. They are eukaryotic cells, plant cells also have a true nucleus along with (animal cells) specialized structures called organelles that carry out different functions.

Diffusion is the net passive movement of particles from a region in which they are in higher concentration to regions of lower concentration. It continues until the concentration of substances is uniform throughout.