The Chapter 4 Concept Check Questions are due on Monday.

The Chapter 4 Test is on Monday.

The T-Shirt vote will be on Tuesday.

Homework: Eukaryopolis - The City of Animal Cells: Crash Course Biology #4

Chapter 4Cell Walls and ECM

You Must Know

• The structure and function of the plant cell wall and the animal ECM.

Cell Walls of Plants

• The cell wall is an extracellular structure that distinguishes plant cells from animal cells

• Prokaryotes, fungi, and some protists also have cell walls

• The cell wall protects the plant cell, maintains its shape, and prevents excessive uptake of water

• Plant cell walls are made of cellulose fibers embedded in other polysaccharides and protein

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Figure 4.25

Secondarycell wall

Central vacuole

Primarycell wall

1 m

Middlelamella

Plasmodesmata

Cytosol

Plasma membrane

Plant cell walls

The Extracellular Matrix (ECM) of Animal Cells

The ECM is made up of glycoproteins

Figure 4.27

1 m

Intermediatefilaments

TEM

0.5 mTEM

0.1 mT

EM

Tightjunction

Tightjunction

Ions or smallmolecules

Extracellularmatrix

Gapjunction

Desmosome

Space between cells

Plasma membranesof adjacent cells

Tight junctions preventfluid from movingacross a layer of cells