IB Biology C2.1 Definitions
This page contains our IB Biology definitions for C2.1. By learning each one of these definitions, you will fully cover the content for IB Biology 'Chemical signalling'.
action potential
The depolarization, repolarization, and hyperpolarization of a neuron
Cytokines
A large group of peptides and small proteins that coordinate immune responses over short and long distances, including interferons (IFs), interleukins (ILs), and tumor necrosis factors (TNFs)
differentiation
The growth and development of cells into specialized cell types
exocytosis
Release of substances into the extra-cellular matrix through fusion of vesicles with the plasma membrane
gene expression
The conversion of genes to proteins to express the gene's coded characteristic
hydrophilic
Attracted to water (water-loving)
hydrophobic
Repelled to water (water-fearing)
ligand
Neutral molecule or anion with a non-bonding pair of electrons (commonly water)
negative feedback
The process whereby substances decrease each other's levels
neuron
A nervous system cell that carries electrical impulses from the brain to the body or vice versa
Neurotransmitters
Chemical messengers released in synapses to carry signals to another neuron, gland, or muscle cell
positive feedback
The process whereby substances increase each other's levels
synapse
The junction between two neurons or between a neuron and receptor or effector cell
synaptic cleft
The space between two neurons or between a neuron and receptor or effector cell
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