The Cell Cycle

Steps in the cell cycle Interphase: No division occurs. Interphase has three subdivisions: G1 S G2

Interphase G1: Gap one first phase, Growth and normal processes take place. No division occurs Longest phase of interphase

Interphase S or Synthesis phase: Second stage DNA replicates making another copy of chromosomes. At the end of this phase, the nucleus will contain two complete sets of DNA. 

Interphase G2: Cells prepare for division. Shortest stage of interphase Spindle fibers, centrioles, etc - are prepared for next stage

Interphase

Mitosis Mitosis: the division of the cell nucleus and its contents. Mitosis has four main stages: Prophase Metaphase Anaphase Telophase

Parent cell Mitosis Cytokinesis Daughter cells

Mitosis Prophase: Chromosomes become shorter, thicker, and become visible. Nuclear envelope begins to disappear. Centrioles are moving toward poles and spindle fibers are forming. Spindle fibers form between centrioles.

Prophase

Mitosis Metaphase: The chromosomes line up in the mid-plane of the cell. Spindle fibers attach to the centromere of the chromosome.

Mitosis Anaphase: Sister chromatids separate at centromeres and move away One group of chromosomes are pulled by the centrioles on the spindle fibers

Anaphase

Mitosis Telophase: Chromosomes are at the poles. The nuclear envelopes begin to form. Nucleolus reforms Spindle fibers disappear Cytokinesis and telophase take place around the same time.

Telophase

Cytokinesis Cytokinesis: The process that divides the cytoplasm. Animal cells - The cell membrane pinches together

Plant Cells In plant cells cytokinesis occurs by forming a cell plate to form the new cell wall.

Answer the following questions Is this an animal or a plant? 2. What phase is this slide in? 3. What helped you determine which phase this slide was in?

Answer the following Is this an animal or a plant? What phase is this slide in? 6. What helped you determine which phase this slide was in?

Answer the following Is this an animal or a plant? What phase is this slide in? 9. What helped you determine which phase this slide was in?

Answer the following Is this an animal or a plant? 11. What phase is this slide in? 12. What helped you determine which phase this slide was in?

Answer the following What phase is the cell the arrow is on in? What phase is the cell to the left of that cell in? 15. Name the two differences between plant mitosis and animal mitosis.

Review Four main stages of the cell cycle: G1- normal growth Synthesis- DNA is copied Gap 2- more growth Mitosis- nuclear division Prophase- chromosomes are visible, nuclear envelope disappears Metaphase- chromosomes line in up in mid-plane Anaphase- chromosomes move away from the mid-plane Telophase- Chromosomes at poles nuclear envelope forms Cytokinesis- divides the cytoplasm Together, these three stages make up interphase.