Cell Structures Involved in Cell Division Section 2.2 BC Science Probe 9 Pages 39-41

Cell Structures Involved in Cell Division Quick Review: Cells can be eukaryotic Have a nucleus surrounded by a membrane Animal and plant cells fit into this category

Cell Structure Involved in Cell Division Quick Review: Or cells can be prokaryotic Have no nucleus These are bacteria

Cell Structures Involved in Cell Division Both prokaryotic cells and eukaryotic cells have to undergo cell division.

The Nucleus The nucleus acts as the control centre of the cell. It directs all cell activities including cell division.

The Nucleus The nuclear membrane allows some materials to pass into and out of the nucleus.

The Nucleus Chromosomes The nucleus contains the material that directs all of the activities of the cell in structures called chromosomes. Nearly all human cells have 23 pairs.

The Nucleus Chromosomes Chromosomes are made of DNA and protein. DNA is a very long molecule that looks like a twisted ladder. The DNA provides the directions for everything that happens in the cell, including cell division to repair worn and damaged cells.

Nucleus Nucleolus The nucleolus is also found in the nucleus. It is the site of production and assembly of the ribosomes. Once the ribosomes are put together, they move out into the cytoplasm.

Ribosomes and Endoplasmic Reticulum Tiny organelles in the cytoplasm Make proteins that the cell needs in order to work properly. They can be free in the cytoplasm, or attached to the endoplasmic reticulum.

Ribosomes and Endoplasmic Reticulum A.K.A. – the ER A series of tubes and flattened sacs that transport materials throughout the cell. If it has ribosomes attached to it = Rough ER Used to transport protein throughout the cell. No ribosomes = Smooth ER Used to manufacture and transport fats in the cell.

Cytoplasm The cytoplasm is inside the cell membrane. Inside the cytoplasm are tiny tubes called microtubules. These allow for movement of organelles in the cell. They also provide support for the cell.

Cytoplasm Centrioles are organelles made of special microtubules. They are found in animal cells. They are active during cell division.