GCSE Biology Revision Notes: Cell Biology
(AQA Focus)
1. Cell Structure & Core Organelles
Cells are the basic building blocks of all living things. Think of a cell like a miniature
factory where different departments (organelles) have specific jobs to do.
Cells are split into two major categories: Eukaryotic and Prokaryotic.
Eukaryotes vs. Prokaryotes
• Eukaryotic Cells: These are complex cells found in plants, animals, fungi, and protists. Their
genetic material (DNA) is securely enclosed inside a distinct nucleus. They are typically
between 10 and 100 micrometres (μm) in size.
• Prokaryotic Cells: These are much simpler, tiny cells (0.1 to 5.0 μm) found in bacteria. They
have no nucleus. Instead, their DNA floats freely in the cytoplasm as a single circular strand.
They also contain tiny extra rings of DNA called plasmids, and completely lack mitochondria
or chloroplasts.
(AQA Focus)
1. Cell Structure & Core Organelles
Cells are the basic building blocks of all living things. Think of a cell like a miniature
factory where different departments (organelles) have specific jobs to do.
Cells are split into two major categories: Eukaryotic and Prokaryotic.
Eukaryotes vs. Prokaryotes
• Eukaryotic Cells: These are complex cells found in plants, animals, fungi, and protists. Their
genetic material (DNA) is securely enclosed inside a distinct nucleus. They are typically
between 10 and 100 micrometres (μm) in size.
• Prokaryotic Cells: These are much simpler, tiny cells (0.1 to 5.0 μm) found in bacteria. They
have no nucleus. Instead, their DNA floats freely in the cytoplasm as a single circular strand.
They also contain tiny extra rings of DNA called plasmids, and completely lack mitochondria
or chloroplasts.
