The Cell Cycle and Mitosis Chapter 9 and 10.1
What is the cell cycle? Repeating sequence of cellular growth and division throughout the life of an organism.
Cell division and why we care about it.
Interphase G1 Phase- Growth 1 S phase – DNA synthesis
G1 Phase- Growth 1 1st Growth Phase = (G1) 1. Cell grows rapidly and carries out routine functions 2. Phase takes most of the cell’s life 3. Muscle and nerve cells never divide, so they remain in G1
S phase- Synthesis Phase Synthesis Phase (S) 1. Cell’s DNA is copied 2. At the end of the stage, each chromosome consists of 2 chromatids attached @ a centromere.
G2- Second Growth Phase Second Growth Phase (G2) 1. Hollow microtubules are assembled 2. Microtubules are used to move chromosomes during mitosis
M phase- Mitosis Mitosis 1. Nucleus is divided into 2 nuclei 2. Each nucleus ends up with the same number of chromosomes as the original cell. 3. Includes prophase, metaphase, anaphase and telophase.
Prophase The cell’s chromatin tightens. Sister chromatids are attached at the centromere Spindle fibers form in the cytoplasm The nuclear envelope seems to disappear. Spindle fibers attach to the sister chromatids
Prophase- Plant and animal cell
Metaphase Sister chromatids are pulled along the spindle apparatus toward the center of the cell. They line up in the middle of the cell.
Metaphase- Plant and animal cell
Anaphase The microtubules of the spindle apparatus begin to shorten. The sister chromatids separate The chromosomes move toward the poles of the cell.
Anaphase- Plant and animal cell
Telophase The chromosomes arrive at the poles and begin to relax. Two new nuclear membranes begin to form and the nucleoli reappear The spindle apparatus disassembles
Telophase- Plant and animal cell
Cytokinesis In animal cells, microfilaments constrict, or pinch, the cytoplasm. In plant cells, a new structure, called a cell plate, forms
Cytokinesis- Plant and animal cell
9.2 Quiz What is the importance of Mitosis? What are the 4 phases of Mitosis? How do prokaryotic cells divide?