Plant cells are mainly composed of cellulose, but also contain hemicellulose, pectin and lignin. Functions: Support, protection and regulation of water absorption.

Collagen, elastin, proteoglycans and adhesion proteins are main components of animal ECM that provides support and is responsible for cell adhesion, migration and wound repair. Plant ECM is cell wall. Basement membrane is more orderly ECM.

Cell junction consist of desmosome, hemi-desmosome, tight junction, gap junction. They are used for cell adhesion, material transport, intercellular communication and the creation of waterproof and protective barriers.

The cell membrane is composed of lipids, proteins, and sugars. Phospholipids enable cell membrane flow. Cholesterol prevents membrane solidification at low temperatures and reduces membrane fluidity at high temperatures. Proteins are mobile in membranes.

Selectively permeable cell membranes control the entry and exit of substances. Proteins in the cell membrane are responsible for recognition, transport, cell junctions, and anchoring in the extracellular matrix.

Simple diffusion and osmosis are both passive transport that do not consume ATP. Substances move from high concentration to low concentration. Osmosis is the movement of water through a semipermeable membrane.

Collagen has a primary structure, a secondary structure, a tertiary structure and a quaternary structure. The three helical peptide chains are twisted together to form a three-stranded helical structure.

Facilitated diffusion is a passive transport aided by transmembrane proteins. Channel proteins include ion channels and aquaporins whose shape don't change. Carrier proteins change shape significantly when transporting substrates. Simple diffusion vs Facilitated diffusion