1 | Cells: the fundamental units of life

Archaeon

One of the two divisions of prokaryotes, often found in hostile environments such as hot springs or concentrated brine 

Bacterium

One of the two divisions of prokaryotes. Some species cause disease. 

Cell

The basic unit from which a living organism is made

Chloroplast

Specialized organelle in algae and plants that contains chlorophyll and serves as site in which photosynthesis takes place

Chromosome

Long, threadlike structures consist of DNA and proteins that carry the genetic information of an organism. Becomes visible and as a distinct entity when a plant or animal cell prepares to divide

Cytoplasm

Contents of a cell that are contained within its plasma membrane - but, in the case of eukaryotes, outside the nucleus

Cytoskeleton

System of protein filaments in the cytoplasm of a eukaryotic cell that gives the cell shape and the capacity for directed movement. Actin filaments, microtubules, and intermediate filaments

Cytosol

Contents of the main compartment of the cytoplasm, excluding the membrane enclosed organelles. What remains after the membranes, cytoskeletal components and other organelles have been removed

DNA

Double stranded polynucleotide formed from two separate chains of covalently linked deoxyribonucleotide units . serves as the cell's source of genetic information that is transmitted from generation to generation

Electron microscope

Instrument that illuminates a specimens using beams of electrons to reveal and magnify the structures or very small objects, such as organelles and large molecules

Eukaryote

An organism whose cells have a nucleus and cytoplasm

Evolution

Process of which gradual modification and adaptation that occurs in living organisms over generations

Fluorescence microscope

Instrument used to visualize a specimen that has been labeled with fluorescent dye. Samples are illuminated with a wavelength of light that excites the dye, causing it to fluoresce.

Genome

The total genetic information carried by all the chromosomes of a cell or organism

Homologous

Possessing identical alleles for a given gene

Micrometer

Unit of length equal to one millionth of a meter

Microscope

Instrument for viewing extremely small objects

Mitochondrion

Membrane-enclosed organelles, that carries out cell respiration

Model organism 

A living thing selected for intensive study as a representative of a large group of species

Nucleus

The prominent, rounded structure that contains the DNA of a eukaryotic cell

Organelle

A discrete structure or subcompartment of a eukaryotic cell that is specialized to carry out a particular function

Photosynthesis

The process by which plants, algae and some bacteria use the energy of light to drive the synthesis of organic molecules from carbon dioxide and water

Plasma membrane

The protein-containing lipid bilayer that surrounds a living cell

Prokaryote

Living cells without a nucleus

Protein

Polymer built from amino acids. Provide cells with their shape and structure, and performs most of their activities

Protozoan

A free-living, nonphotosynthetic, single-celled, motile eukaryotic

Ribosome

Large macromolecular complex, composed of ribosomal RNAs and ribosomal proteins, that translates messenger RNA into proteins

RNA

Molecules produced by the transcription of DNA. single stranded. Composed of covalently linked ribonucleotide subunit