Biology Terms

Abdomen:  The abdomen refers to the region between the pelvis (pelvic brim) and the thorax (thoracic diaphragm) invertebrates, including humans. The space constituting the abdomen is termed the abdominal cavity. The borders of the abdominal cavity are comprised of the posterior peritoneal surface, the anterior abdominal wall, the inferior pelvic inlet, and the superior thoracic diaphragm. The abdomen functions to house the digestive system and provides muscles essential for posture, balance, and breathing.

Abiotic – nonliving, inanimate, characterized by the absence of life; of inorganic matter.

Activation energy – The energy required to complete a chemical reaction.

Aerobic: living or occurring only in the presence of oxygen.

Amino acid – The “building blocks” of proteins.

Amino sugar – A sugar molecule with an amine group attached instead of one of its hydroxyl groups.

Anatomy: Anatomy is a branch of natural science which deals with the structural organization of living things. Anatomy is the study of the structure and relationship between body parts.

Antibiotic: any substance that can destroy or inhibit the growth of bacteria and similar microorganisms.

Antibody : A protein produced by the immune system meant to incapacitate and tag foreign bodies for disposal.

Antigen – A protein attached to the surface of a foreign body which can be recognized by proteins on immune cells.

Apoptosis – Programmed cell death that occurs in multicellular organisms, preceded by distinct changes to the morphology and biochemistry of the cell. Common during development and also used to prevent disease.

ATP – The “energy currency” of the cell. The chemical bonds in the ATP molecule store energy that can be used to accomplish life functions.

Bacteria: Bacteria are single-celled microorganisms with prokaryotic cells, which are single cells that do not have organelles or a true nucleus and are less complex than eukaryotic cells. Bacteria with a capital B refers to the domain Bacteria, one of the three domains of life. The other two domains of life are Archaea, members of which are also single-celled organisms with prokaryotic cells, and Eukaryota. Bacteria are extremely numerous, and the total biomass of bacteria on Earth is more than all plants and animals combined.

Binary fission – The method by which bacteria reproduce asexually through dividing.

Biodiversity – Large variety of organisms.

Biofilm: a thin film of mucus created by and containing a colony of bacteria and other microorganisms.

Biome – A large, naturally occurring community of life forms. Biomes can be thought of as “types of ecosystems.” Rainforest, tundra, savanna, temperate forest, and temperate grassland are examples of biomes.

Biomolecule – Biomolecule, also called biological molecule, any of numerous substances that are produced by cells and living organisms. Biomolecules have a wide range of sizes and structures and perform a vast array of functions. The four major types of biomolecules are carbohydrates, lipids, nucleic acids, and proteins.

Bioremediation: the use of biological organisms, usually microorganisms, to remove contaminants, especially from soil or polluted water.

Biotechnology: the use of living organisms (especially microorganisms) in industrial, agricultural, medical, and other technological applications.

Biotic factor – A living element of an ecosystem, such as a plant, animal, or bacteria. Biotic and abiotic factors together make up an ecosystem.

Biotransformation: the changes (both chemical and physical) that occur to a substance (especially a drug) by the actions of enzymes within an organism.

Capillary action – The mechanism by which trees draw water up through their roots to feed their leaves.

Carbon cycle: the physical cycle of carbon through the earth’s biosphere, geosphere, hydrosphere, and atmosphere that includes such processes as photosynthesis, decomposition, respiration and carbonification.

Carcinoma: Carcinoma is a term used to describe cancer derived from epithelial cells that line various tissues throughout the body. In addition, malignant tumours that have an unknown primary origin, but share histological characteristics with epithelial cells (e.g., stratification, pseudostratification, cytokeratin production, mucin, etc.) are also classified as carcinomas. Depending on the location, carcinomas can be surgically removed, or treated with conventional radiation or chemotherapy.

Cell: The cell (meaning “small room”) is the basic structural, functional, and biological unit of all known living organisms. All living organisms are made up of building blocks we call the cell. Many living things consist of vast numbers of cells working in concert with one another.

Cell membrane – A membrane made up of phospholipids, and which separates from the inside of a cell from the outside.

Cellular respiration – Energy from nutrients is converted into ATP.

Chemosynthetic: Using chemical reactions as energy source. Eg: Nitrosomonas Bacteria.

Chemotroph – An organism that obtains energy mainly from carbon dioxide and from other inorganic chemicals through a process called chemosynthesis

Chloroplast: an organelle found in the cells of green plants and photosynthetic algae where photosynthesis takes place.

Classification: Grouping of organisms into categories on the basis of similarities & differences.

Coenzyme – A complex enzyme contains a non-protein part, called a prosthetic group or co-enzymes. Co-enzymes are very essential for the biological activities of the enzyme.

Cohesion – The tendency of molecules to stick to other molecules like themselves.

Convergent evolution – Occurs when unrelated life forms evolve very similar solutions to environmental problems.

Conjugation: the temporary fusion of organisms, especially as part of sexual reproduction.

Crista: cristae (singular crista) are the internal compartments formed by the inner membrane of a mitochondrion.

Cyanobacteria: photosynthetic prokaryotic microorganisms, of phylum Cyanobacteria, once known as blue-green algae.

Daughter Cells: Daughter cells are produced after a single cell undergoes cell division. During mitosis, one pair of daughter cells is created after one round of DNA replication. During meiosis, a single round of DNA replication is followed by 2 rounds of cell division. This creates two sets of daughter cells, each of which has a haploid genome.

Ear: The ear is the organ found in animals which are designed to perceive sounds. Most animals have some sort of ear to perceive sounds, which are actually high-frequency vibrations caused by the movement of objects in the environment. The human ear picks up and interprets high-frequency vibrations of air, while the sound-sensing organs of aquatic animals are designed to pick up high-frequency vibrations in water. Most vertebrates have two ears: one on either side of the head.

Ecosystem – A biological community of organisms and their environment. “Ecosystem” and “biome” are very similar terms, although “biome” usually refers to a specific type of ecosystem such as a rainforest, tundra, etc.

Electron Transport Chain(ETC):

The sequence of reactions whereby the reduced forms of the coenzymes are reoxidized by molecular O2 known as electron transport chain

The chain has principle electron carriers

  • NADH dehydrogenase.
  • Succinate dehydrogenase.
  • Coenzyme Q.
  • Cytochromes b2, bH, b560, c1, c, a, & a3 and iron sulphur proteins.

Each of them functions as a redox system with its prosthetic group or metal ions changing alternatively to reductant and oxidant – forms during electron transport.

Energy Pyramid – A graphic illustration which is used to show how energy flows through an ecosystem. These pyramids typically have plants, which efficiently and directly harvest sunlight, at the “bottom” and the top predator at the top, with herbivores and intermediate prey species in the middle.

Endomembrane: all the membraneous components inside a eukaryotic cell, including the nuclear envelope, endoplasmic reticulum, and Golgi apparatus

Endosymbionts – Organisms that live within other organisms.

Protein- Any of a group of complex organic macromolecules that contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur and are composed of one or more chains of amino acids. Proteins are fundamental components of all living cells and include many substances, such as enzymes, hormones, and antibodies, that are necessary for the proper functioning of an organism. They are essential in the diet of animals for the growth and repair of tissue and can be obtained from foods such as meat, fish, eggs, milk, and legumes.