Science, Tech, Math › Science Biology Prefixes and Suffixes: proto- Share Flipboard Email Print Amoeba Protozoan Feeding. Eric Grave/Brand X Pictures/Getty Images Science Biology Basics Cell Biology Genetics Organisms Anatomy Physiology Botany Ecology Chemistry Physics Geology Astronomy Weather & Climate By Regina Bailey Biology Expert B.A., Biology, Emory University A.S., Nursing, Chattahoochee Technical College Regina Bailey is a board-certified registered nurse, science writer and educator. Her work has been featured in "Kaplan AP Biology" and "The Internet for Cellular and Molecular Biologists." our editorial process Regina Bailey Updated July 05, 2019 Biology Prefixes and Suffixes: proto- Definition: The prefix (proto-) means before, primary, first, primitive, or original. It is derived from the Greek prôtos meaning first. Examples: Protoblast (proto - blast) - a cell in the early stages of development that differentiates to form an organ or part. Also called a blastomere. Protobiology (proto - biology) - relating to the study of primitive, minute life forms such as bacteriophages. It is also known as bacteriophagology. This discipline concentrates on the study of organisms that are smaller than bacteria. Protocol (proto - col) - the step by step procedure or overall plan for a scientific experiment. It can also be the plan for a series of medical treatments. Protoderm (proto - derm) - the outer, most primary meristem that forms the epidermis of plant roots and shoots. The epidermis is the primary barrier between the plant and its environment. Protofibril (proto - fibril) - the initial elongated group of cells that form in the development of a fiber. Protogalaxy (proto - galaxy) - a gas cloud that will over time, form a galaxy. Protolith (proto - lith) - the original state of a rock prior to metamorphism. For example, the protolith of quartzite is quartz. Protolithic (proto - lithic) - of or relating to the first part of the Stone Age. Protonema (proto - nema) - an initial stage in the development of mosses and liverworts that is observed as a filamentous growth, which develops after spore germination. Protopathic (proto - pathic) - relating to sensing stimuli, such as pain, heat, and pressure in a nonspecific, poorly localized manner. This is thought to be done by a primitive type of peripheral nervous system tissue. Protophloem (proto - phloem) - narrow cells in phloem (plant vascular tissue) that are formed first during tissue growth. Protoplasm (proto - plasm) - the fluid content of a cell inclusive of the cytoplasm and the nucleoplasm (located within the nucleus). It contain fats, proteins, and additional molecules in a water suspension. Protoplast (proto - plast) - the primary living unit of a cell consisting of the cell membrane and all of the content within the cell membrane. Protopod (proto - pod) - of or relating to an insect in its larval stage when it doesn't have either limbs or a segmented abdomen. Protoporphyrin (proto - porphyrin) - a porphyrin that combines with iron to form the heme portion in hemoglobin. Protostele (proto - stele) - a stele type that has a xylem core encased by a phloem cylinder. It typically occurs in the roots of plants. Protostome (proto - stome) - an invertebrate animal in which the mouth develops before the anus in the embryonic stage of its development. Examples include arthropods like crabs and insects, some types of worms, and mollusks like snails and clams. Prototroph (proto - troph) - an organism that can acquire nourishment from inorganic sources. Prototrophic (proto - trophic) - an organism that has the same nourishment requirements as the wild type. Common examples include bacteria and fungi. Prototype (proto - type) - the primitive or ancestral form of a given species or group of organisms. Protoxide (proto - xide) - an element's oxide that has the lowest amount of oxygen compared to its other oxides. Protoxylem (proto - xylem) - the portion of a plant's xylem that develops first that is typically smaller than the larger metaxylem. Protozoa (proto - zoa) - tiny unicellular protist organisms, whose name means first animals, that are motile and capable of ingesting food substances. Examples of protozoa include amoebas, flagellates and ciliates. Protozoic (proto - zoic) - of or relating to protozoans. Protozoon (proto - zoon) - an additional name for protozoans. Protozoology (proto - zo - ology) - The biological study of protozoans, particularly those that cause disease. Protozoologist (proto - zo - ologist) - a biologist (zoologist) who studies protozoans, especially disease causing protozoans. Key Takeaways The prefix proto- can refer to being original, first, primary, or primitive. Biology has a number of important proto- prefix words like protoplasm and protozoa.proto- gets its meaning from the Greek prôtos which means first.As is the case with other similar prefixes, being able to understand prefix meanings is very helpful to biology students understanding their coursework.