Post on 24-Feb-2016
description
The Cell Cycle5A
How eukaryotic cells divide to
make new cells
Just like people have phases of development,
Cells have phases too.
In somatic (body) cells, a parent cell produces 2 daughter cells.
The purpose of mitosis is for growth and repair of tissue.
Three Phases or Stages
1. Interphase2. M (Mitosis) phase3.Cytokinesis
Interphase
Interphase DNA and organelles replicate
Cell spends most of its life in this stage
Stages of InterphaseG1 (growth)
S (synthesis)
G2 (growth)
G1 (growth)
• Aka First Gap• The cell grow larger• Makes proteins and
organelles
S (synthesis)
• DNA replication occurs - genetic material is duplicated so each daughter cell contains the same amount of genetic material as the parent cell
• Chromosomes duplicate to form sister chromatids
G2 (growth)
• Aka Second Gap• More growth & protein
synthesis occurs• preparing for cell division
M phase
• Aka Mitosis • Shortest of all phases• Division of the
nucleus
Mitosis
Nucleus divides Duplicated DNA is divided
into two new nuclei
Stages of Mitosis
ProphaseMetaphaseAnaphaseTelophase
Prophase
Prophase
• Nuclear membrane breaks down• Genetic material (chromosomes)
enlarges, thickens &condenses• In the cytoplasm, Centrioles
migrate to opposite ends of poles•Microtubules attach to centrioles
Prophase
Metaphase
Metaphase
• Duplicated chromosomes line up on the equator of the cell
• Spindles attach to chromosomes at the centromere & pull the sister chromatids into a line in the center of the cell
Metaphase
Anaphase
Anaphase
• Shortest phase• As the spindle contracts,
the sister chromatids separate and are pulled to opposite sides of the cell
Anaphase
Telophase
Telophase
• New nuclear membranes form to separate the genetic material
• Chromosomes shrink• Spindle breaks apart
Telophase
Mitosis
Cytokinesis
Cytokinesis
• Occurs AFTER telophase and BEFORE interphase
• Cytoplasm divides• Forms 2 new cells
Cytokinesis
http://outreach.mcb.harvard.edu/animations/cellcycle.swf
Identify the stage of the cell cycle…
Identify the stage of the cell cycle…
Identify the stage of the cell cycle…
Identify the stage of the cell cycle…
http://bio.rutgers.edu/~gb101/lab2_mitosis/index2.html
What happens when cells divide at an uncontrollable rate?
CANCER5D
Cancer is caused by the loss of cell’s ability to control division. Cancer cells divide uncontrollably.
Causes of Cancer
• Tobacco•Radiation exposure•Viral infections (HPV)•Genetics
http://www.mhhe.com/biosci/genbio/virtual_labs/BL_23/BL_23.html