Cell Structures Involved in Cell Division Section 2

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 • Ribosomes – 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 • 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.