The Cell Cycle Mitosis Pg. 204- 210 in your book
Quick Facts About the Cell Cycle • The cell cycle is common to all living things • It is a sequence of growth and division of a cell • Two major periods of the cell cycle: I. Interphase II. Mitosis
Interphase • The time between cell division when a cell grows and replicates (makes copies of DNA) • The majority of a cell’s life is spent in interphase -Growth Phase I (G1): Proteins are made, the cell grows and organelles increase in size and number -Synthesis Phase (S)- DNA replicates; the purpose of this is so that the new cell can have the exact genetic copy -Growth Phase (G2)- more proteins are made, centrioles used for cell division are copied and being to make spindles
Mitosis -A continuous process that has four phases of the division of the nucleus -This is the process where two daughter cells are formed, each containing a complete set of chromosomes.
Prophase • The first stage of Mitosis • The longest mitotic phase 1. Chromosomes appear because chromatin is condensing -What is condensing? Coiling and getting thicker 2. Centrioles move to the poles of the cell 3. Centrioles begin to form spindle -these attach to the centromeres which hold together the sister chromatids 4. Nuclear membrane begins to disappear 5. Nucleolus disappears
Metaphase • Chromosomes become attached to the spindle fibers by their centromeres • Chromosomes line up across the middle of the cell -Also known as the equator
Anaphase • Chromosome separate and one sister chromatid of each pair moves to each pole of the cell
Telophase • Chromosomes arrive at opposite ends of the cell • Two nuclei form • It’s the reverse of prophase
Cytokinesis • Finally the end! • This is the division of cytoplasm • This happens in two different ways 1. In animal cells- the cytoplasm and plasma membrane pinch in along the equator to create cleavage furrow 2. In plant cells- cell plate forms along the equator -Plants have a rigid cell wall so the plasma membrane does not pinch in -A cell plate is laid down across the equator and a cell membrane forms around each cell and new cells walls form to complete the separation.
Plant Cell cytokinesis begins with a series of vesicles that form at the equator of the cell, which subsequently join until the cell is divided in two. Animal Cell cytokinesis starts with a cleavage furrow or indentation around the middle that eventually pinches in, dividing the cell in two Plant Cell Cytokinesis vs. Animal Cell Cytokinesis
Cell Cycle Summary Interphase • G1 stage- Growth & development of the cellProtein synthesis • S-phase-Chromosome replication viaDNA synthesis • G2 stage- Growth & developmentOrganelle Replication Mitosis Prophase- Replicated chromosomes condense , Spindle fibers form Metaphase- Replicated chromosomes align at center Anaphase-Sister chromatids separateDaughter chromosomes move to poles Telophase- New nuclear membranes formSpindle fibers disappear Cytokinesis- Cell divides into two daughter cells
Now how am I supposed to remember all of this? • Remember PMAT -Prophase -Metaphase -Anaphase -Telophase (yes, I know it is simple but it also helped me remember!) -Just make sure to remember that Interphase comes before PMAT and Cytokinesis comes at the end!
Now the fun begins!! • You get to make a cell cycle booklet! -You are going to make a booklet of the cell cycle, making sure to include interphase and mitosis -Interphase should include the 3 stages (draw and briefly describe events for G1, S and G2 phases) -Draw, label and briefly describe the stages of mitosis (If you draw it, you must label it!) -The last page of your booklet should show cytokinesis for both animal and plant cells -Structures to be labeled: Nucleolus, Centriole, Spindle Fibers, Daughter Cells, Chromatin, Centromere, Cleavage Furrow, Nucleus, Sister chromatids, Cell plate Things to really pay attention to that you will be graded on! -Accuracy -Neatness -Making sure all requirements are met above!