Chapter 2 - Cells

• The cell membrane is a very thin layer of protein and fat. It is said to be partially permeable.

• All plant cells are surrounded by a cell wall made mainly of cellulose.
• Animal cells NEVER have cell walls made of cellulose.
• The cellulose cell wall is fully permeable. 

• Many different metabolic reactions take place in the cytolpasm. 

• Plant cells have very large vacuoles, which contain a solution of sugars and other substances called cell sap.
• Animal cells have much smaller membrane-bound spaces, called vesicles, which may contain food or water. 

• Chloroplasts contain the green pigment chlorophyll. Chlorophyll absorbs energy from sunlight, and this energy is then used for making food for the plant by photosynthesis.

Comparisons of plant cells and animals cells features

Plant cells

Animal cells

have a cellulose cell wall outside the cell membrane

have no cell wall

have a cell membrane

have a cell membrane

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