IB Biology B - Form and Function Key Definitions

Abiotic factors are non-living components like temperature, water availability, salinity, and soil type.

Absorption is the process by which digested nutrients are transported into the body, primarily occurring in the small intestine.

Active transport is the movement of molecules or ions across a membrane against their concentration gradient (from low to high concentration), which requires energy.

The attraction between water molecules and other surfaces, enabling water to cling to them and move against gravity.

Amphipathic: A molecule that has both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.

A molecule with both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions, such as a phospholipid.

Antagonistic muscles are pairs that work in opposition—when one contracts, the other relaxes.

Assimilation is the process by which absorbed nutrients are transported to cells and used for growth, repair, and energy production.

The enzyme that uses the energy from the proton gradient to catalyze the synthesis of ATP from ADP and inorganic phosphate.

Valves located between the atria and ventricles that prevent the backflow of blood.

Biodiversity is the total variety of life on Earth.

Large-scale groupings of ecosystems sharing similar abiotic factors (e.g., temperature, precipitation).

The Bohr shift (or Bohr effect) describes how haemoglobin’s affinity for oxygen decreases in the presence of high levels of carbon dioxide (CO₂) or in acidic environments (lower pH).

Buoyancy is the upward force exerted by a fluid (liquid or gas) on an object immersed in it.

Cell-adhesion molecules (CAMs) are proteins that span the phospholipid bilayer of the membrane.

A specialized protein embedded in the membrane, allowing specific ions or molecules to diffuse across.

The attraction between water molecules due to hydrogen bonding.

Specialized cells in phloem that assist sieve tube elements by providing metabolic support, including energy production.

Two species cannot coexist indefinitely in the same ecological niche if resources are limiting.

The difference in concentration of a substance (e.g., oxygen or carbon dioxide) between two regions.

Condensation is a reaction where two molecules combine, releasing water.

Definition:

Coronary arteries are specialized vessels branching from the aorta.

A statistical measure that quantifies the strength and direction of the relationship between two variables.

A group of proteins that regulate the cell cycle by activating cyclin-dependent kinases (CDKs).