Cells

Types of Cell:

-Prokaryotic - small, simple, bacteria

-Eukaryotic - big, complex, everything except bacteria

-Unicellular - one single cell - zygote, algae, amoeba, bacteria 

-Multicellular - millions/billions of cells - cells cannot be big. Humans and plants.

Specialised Cells: ( a cell adapted for particular function)

-Red blood cells - biconcave, no nucleus, large surface area - carry more oxygen

-Epithelial cell - gut lining - thin tissue forms outer layer of body's surface - must be able to receive nourishment- diffusion. Microvilli - maximise surface area so membrane can hold lots of carrier proteins. Mitochondria - ATP for active transport

Tissue - Group cells - same function - 4 main types: muscle, connective, nerve, epithelia

Organ- Group tissues (same function)

System - Group of organs - perform major function

E.g. Nervous system - brain, spinal cord, nerves. Digestive - liver, pancreas, tongue, oesophergus

Mitochondria - Cristae - folds inner membrane. Matrix - enzyme filled fluid

Organelles

Mitochondria - respiration - round, elongated, 

Ribosomes - protein synthesis - small, dense, 

Golgi body - synthesis of chemicals - stack flattened membrane…