Biology terminology

Biology, the scientific study of life and living organisms, encompasses a wide range of concepts and terms that are essential for understanding the complexities of life. This article aims to provide an overview of key terminology used in biology, offering definitions and explanations to facilitate a deeper understanding of this diverse field.

A

• Adaptation - The process by which an organism becomes better suited to its habitat. This can involve structural, physiological, or behavioral changes.

• Allele - One of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent.

• Amino acid - The building blocks of proteins. There are 20 different amino acids that can be combined to make a protein.

• Autotroph - Organisms that produce their own food from inorganic substances, such as carbon dioxide and water, typically through photosynthesis. Plants are the most well-known autotrophs.

B

• Biodiversity - The variety of life in the world or in a particular habitat or ecosystem. It includes diversity within species, between species, and of ecosystems.

• Biome - A large community of plants and animals that occupies a distinct region defined by its climate and dominant vegetation. Examples include forests, deserts, and tundras.

C

• Cell - The basic structural, functional, and biological unit of all known living organisms. Cells are the smallest unit of life that can replicate independently.

• Chlorophyll - A green pigment found in the chloroplasts of plants, algae, and some bacteria. It absorbs light to provide energy for photosynthesis.

• Chromosome - A long DNA molecule with part or all of the genetic material of an organism. Most eukaryotic cells have their DNA arranged in chromosomes within the nucleus.

D

• DNA (Deoxyribonucleic Acid) - The molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses.

• Dominant Allele - An allele that expresses its phenotypic effect even when heterozygous with a recessive allele.

E

• Ecosystem - A community of living organisms in conjunction with the nonliving components of their environment, interacting as a system.

• Endosymbiosis - The theory that explains the origin of eukaryotic cells from prokaryotes, where one organism lives inside the other and both benefit from the relationship.

F

• Fossil - The remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.

G

• Gene - A unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

• Genotype - The genetic constitution of an individual organism. It contrasts with the phenotype, which is the observable characteristics of an organism.

H

• Heterotroph - Organisms that obtain their nutritional requirements from organic substances. The vast majority of all living organisms are heterotrophic, including humans.

I

• Inheritance - The process by which genetic information is passed on from parent to child. This is a fundamental principle of genetics.

J

• Junk DNA - A colloquial term for regions of DNA that are noncoding. Despite its name, much of this DNA plays important regulatory roles.

K

• Karyotype - The number and visual appearance of the chromosomes in the cell nuclei of an organism or species.

L

• Lipid - Any of various organic compounds that are insoluble in water. Lipids include fats, oils, waxes, and certain vitamins.

M

• Mitochondria - Organelles found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur. They have their own DNA and are involved in energy production.

N

• Nucleus - A membrane-bound organelle found in eukaryotic cells that contains most of the cell's genetic material.

O

• Osmosis - The process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one.

P

• Photosynthesis - 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.

• Phenotype - The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Q

• Quorum sensing - A system of stimuli and response correlated to population density. Quorum sensing enables bacteria to regulate gene expression according to the density of their population.

R

• Recessive allele - An allele that produces its characteristic phenotype only when its paired allele is identical.

S

• Species - The basic unit of biological classification and a taxonomic rank. A species is often defined as the largest group of organisms capable of interbreeding and producing fertile offspring.

• Stem Cell - Undifferentiated cells capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cell arise by differentiation.

T

• Transcription - The process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).

• Translation - The process in which cellular ribosomes create proteins from the mRNA produced during transcription.

U

• Umbilical cord - A flexible cordlike structure containing blood vessels and attaching a mammalian fetus to the placenta during gestation.

V

• Vaccine - A biological preparation that provides active acquired immunity to a particular disease. Vaccines contain an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins.

W

• Water cycle - The cycle of processes by which water circulates between the earth's oceans, atmosphere, and land, involving precipitation as rain and snow, drainage in streams and rivers, and return to the atmosphere by evaporation and transpiration.

X

• Xylem - The vascular tissue in plants that conducts water and dissolved nutrients upward from the root and also helps to form the woody element in the stem.

Y

• Y Chromosome - One of the two sex chromosomes in mammals, including humans, and many other animals. The Y chromosome is the sex-determining chromosome in many species, since it is the presence or absence of Y that determines male or female sex.

Z

• Zygote - A eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information necessary to form a new individual.

Also see

• Glossary of biology