The Cell Theory & Mitosis

The Cell Theory All organisms are made up of one or more cells. Cells are the basic unit of structure and function in all organisms. All cells come from cells that already exist.

All organisms are made up of one or more cells. Unicellular Multicellular

Cells are the basic unit of structure and function in living things. Cells are the building blocks of living things like concrete blocks are the building blocks of houses.

All cells come from cells that already exist. This is where cell division and mitosis come into play.

How does the cell know how to divide? Cell Division Reproduction Growth Repair Why do cells divide? How does the cell know how to divide? The DNA has the instructions for all of the cell’s activities.

Cell Cycle 3 Parts The sequence of development and division of a cell Interphase - Preparation Mitosis – Cell division Cytokinesis – Splitting Adult human cell: ~24 hrs 18-20 hours in interphase 2 hours in mitosis Embryonic cells: 30 min. How long does it take?

Interphase What happens Cell doubles in size DNA replicates Organelles double in number

Mitosis: PROPHASE What happens DNA forms chromosomes Spindle forms Centrioles move toward opposite poles Nuclear membrane begins to disappear

Mitosis: METAPHASE What happens Nucleus has disappeared completely Chromosomes line up in the middle of the cell “equator”

Mitosis: ANAPHASE What happens Centromeres divide Chromatids separate and move to opposite poles

Mitosis: TELOPHASE What happens Nuclear membrane forms around each group of chromosomes Chromosomes unwind Cytokinesis begins

Cytokinesis Cytoplasm divides One cell becomes 2 cells What happens

Learning Scale 4 - Explain how you would justify each part of the cell theory. 3 - Explain the role of DNA in the cell. 2 - Describe the parts of the cell theory. 1 - Identify the levels of organization.