IB Biology Ultimate Guide

Cell Biology

The study of the structure and function of cells, the basic units of life.

Cell Theory

States that all living organisms are made of cells, cells are the smallest units of life, and all cells come from pre-existing cells.

Prokaryotic Cells

Simple cells without a nucleus or membrane-bound organelles, e.g., bacteria.

Eukaryotic Cells

Complex cells with a nucleus and membrane-bound organelles, e.g., animal and plant cells.

Plasma Membrane

A phospholipid bilayer that controls the movement of substances in and out of the cell.

Diffusion

The process of particles moving from an area of higher concentration to an area of lower concentration.

Osmosis

The diffusion of water across a semipermeable membrane.

Mitosis

A type of nuclear division for growth, repair, and asexual reproduction, consisting of four stages: prophase, metaphase, anaphase, and telophase.

Cytokinesis

The division of the cytoplasm following mitosis.

Cyclins

Molecules that regulate the progression of cells through the cell cycle.

Endosymbiotic Theory

Explains the origin of eukaryotic cells as a symbiotic relationship between primitive eukaryotic and prokaryotic cells.

Stem Cells

Undifferentiated cells with the potential to become various types of specialized cells.

Water

Often called the universal solvent; essential for life due to its unique properties.

Macromolecules

Large molecules, including carbohydrates, lipids, and proteins, critical to cell function.

Enzymes

Biological catalysts that speed up chemical reactions by lowering activation energy.

DNA Replication

The process of copying DNA to ensure that genetic information is passed on during cell division.

Transcription

The process of copying a segment of DNA into messenger RNA (mRNA).

Translation

The process of decoding mRNA to produce a specific protein.

Genetic Code

The set of rules by which information encoded within genetic material is translated into proteins.

Gene Expression

The process by which information from a gene is used to synthesize a functional product, typically a protein.

Biotechnology

The manipulation of living organisms or their components to develop products and processes.

PCR (Polymerase Chain Reaction)

A technique used to amplify specific DNA sequences.

GMOs (Genetically Modified Organisms)

Organisms whose genetic material has been altered for specific traits.

Mutations

Changes in the DNA sequence that can affect genetic information.

Nutrient Cycling

The movement and exchange of organic and inorganic matter back into the production of living matter.

Ecological Succession

The process by which ecosystems change and develop over time.