Cell Cycle and Mitosis SBI3U @ RHSA
Cell Cycle • The life cycle of all cells has two main parts: • Interphase • Mitosis and cytokinesis
Interphase • A cell spends most of its lifetime in interphase growing and replicating chromosomes. • Interphase is divided into: • G1 phase • S phase • G2 phase
Interphase: G1 phase • During the G1, or growth 1 phase of interphase, the cell makes new molecules and grows larger. • This phase can be long or short depending on the type of cell and the health of an organism.
Interphase: S phase • S is for synthesis of more DNA. • During the S phase the uncoiled chromosomes, called chromatin, are replicated or duplicated. • During interphase, the nucleus looks like a dark blob (individual chromosomes are not visible).
Sister Chromatids • During replication single stranded chromosomes become double stranded chromosomes. • The 2 strands are identical to each other and are called sister chromatids. A centromere holds chromatids together.
Interphase: G2 phase • During the G2 or growth 2 phase the cell again synthesizes more molecules and grows larger.
Mitosis • Only a very short part of a cell’s life is spent in mitosis. • During mitosis all of the cell’s chromosomes are evenly divided and they move to opposite ends of the cell • Mitosis has 4 steps: prophase, metaphase, anaphase and telophase
Cytokinesis • After mitosis, the cell divides all the cytoplasm and organelles in the process of cytokinesis.
Online resources Mitosis animation • http://www.cellsalive.com/mitosis.htm • Mitosis videos • http://www.sumanasinc.com/webcontent/animations/content/mitosis.html • http://www.biostudio.com/d_%20Mitosis.htm Mitosis quizzes • http://school.discoveryeducation.com/quizzes6/muskopf/mitosis1.html • http://www.phschool.com/science/biology_place/biocoach/mitosisisg/quiz.html • http://local.brookings.k12.sd.us/biology/ch10celldivision/mitosis_review.htm
More websites Cell Cycle Game http://www.nobelprize.org/educational/medicine/2001/index.html Cell Division Powerpoint www.africangreyparrott.com/Mitosis.ppt