Cells The Building Blocks Of Life

1. Cells The Building Blocks Of Life

2. At the end of the lesson, pupils will be able to: • draw and name the parts of a typical animal cell. • draw and name the parts of a typical plant cell. • describe the functions of the various parts of a cell. • distinguish the differences between a plant cell and an animal cell.

3. The simplest organisms are made up of only one cell. They are known as unicellular organisms. Paramecium Source: Encarta

4. Humans and other organisms are made up of more than one cell. They are known as multicellular organisms. Jaguar Liliac Source: Encarta

5. The cell membrane • is a thin partially-permeable membrane surrounding the cell. • allows some substances but not all substances to pass through it.

6. Cytoplasm • is a jelly-like substance containing tiny structures and chemicals. • is where many chemical reactions take place. • fills the cell in the animal cell. • forms a thin lining in the plant cell.

7. Nucleus • contains chromosomes which are thread-like structures that contain the genes. The genes are passed down from the parents to their off springs and determine what an organism looks like and how it behaves. • controls all the chemical reactions of the cell.

8. Vacuoles • are small spaces in the animal cells that contain air, liquid or food particles. • are large spaces that are filled with a liquid known as cell sap in plant cells. The cell sap contains water and dissolved substances such as salt and sugar. The cell sap also makes the cell firm when filled with water.

9. Cell wall • is a thick layer which is found only in the plant cell. • is made up of a rough substance called cellulose. • supports, protects and gives the plant cell its regular shape. • is not found in the animal cell.

10. Chloroplasts • are found only in the plant cells. • are tiny discs containing a green pigment called chlorophyll. Chlorophyll is an essential material that helps the plant to make food in the presence of sunlight during photosynthesis.

11. Unknown source

12. Animal Cell The cytoplasm fills the whole cell. Vacuoles are small and numerous. Absence of chloroplasts. Absence of cellulose cell wall. Plant Cell The cytoplasm is reduced to a thin lining. Vacuoles are big and few. Presence of chloroplasts. Presence of cellulose cell wall. Differences between an animal cell and a plant cell: Special thanks to YS