Cell Cycle and Cell Division
The Cell Cycle is the series of events that take place in the cell from one cell division to another.
Cell Cycle includes: 1-Interphase 2-Mitosis 3-Cytokinesis
Phases of the Cell Cycle page 160 1)Interphase cell grows and organelles duplicate, Dna is copied and the chromosomes duplicate in CHROMATIDS, cell grows more and prepares for cell division. The cells that will not divide anymore are always in Interphase. 2)Mitosis when the nucleus divide 3)Cytokinesis when the organelles and the cytoplasm divides creating 2 identical cells it is different in plant and animal cells
**What is Mitosis????? Mitosis is the process in which the nucleus of a cell divides to generate two identical nuclei.
****Mitosis and Trait Diversity Identical nucleus have exact copies of the DNA, so the cells will be identical,too. Mitosis does not contribute to trait diversity in the population
Cell Division: Examples
Lizard - regeneration of the leg
Starfish - regeneration
Salamander - regenration
Regeneration in humans
Flatworms - regeneration
Plant Growth
All these examples are a result of Cell Division Other examples: dead skin replacement human growth reproduction of unicellular organisms - as shown below
**Why is cell division important? Replacement of dead cells Regeneration of body parts Growth of organisms Reproduction of unicellular organisms
Phases of Mitosis Document school website, page 162 - don t forget to read the additions we made during class
Centriole is an organelle composed of protein They appear, in pairs, close to the nucleus during cell division. The spindle fibers will form between the two centrioles and are attached to the centromere of a duplicated chromosome. Spindle Fibers will pull the chromatids apart during cell division
Centrioles are present only in animal cells and some unicellular plant cells Plant mitosis takes place with protein microtubules forming spindle fibers but without the help of centrioles.
Phases of Mitosis Document school website, page 162 - read and check the additions we did during class. Prophase Metaphase Anaphase Telophase end of Mitosis Cytokinesis Plant and Animal cell
C Y T O K I N E S I S Contractile ring pinches the membrane and the cell divides in the pinched area A new membrane forms inside the cell
What cells go through Cell Division? Multicellular Organisms have two types of cells that divide: a) Somatic Cells ( soma = body in Greek) are all the cells in our bodies They will go through Mitosis and make our body grow, replace our skin, etc.
What cells go through Cell Division? Second type of cell: b) Sex Cells or gametes: two types egg (females) and the sperm (males). Participate in sexual reproduction, generating new organisms The sex cells are formed through Meiosis a different type of cell division and, they will not go through Mitosis
Page 163 - The results of Mitosis and Cell Division *At the end of Mitosis, there are 2 nucleus with 46 chromosomes - 23 pairs of homologous *At the end of Cell Division - 2 identical cells with 46 chromosomes - 23 pairs of homologous (each one of the new nucleus go to one of the new cells)
Types of Asexual Reproduction organisms come from one parent Read page 164 and underline: 1) the 2 different types of reproduction 2) the 2 types of Asexual Reproduction and how they happen 3) underline the process of regeneration
Types of Asexual Reproduction organisms come from one parent Budding - Ex: yeasts. Two new organisms are made from one single parent. The new organisms are identical to the parent cell. Binary Fission reproduction in unicellular prokaryotic organisms - Two new organisms are made from one single parent. The new organisms are identical to the parent cell. Regeneration of dead cells, body parts for certain organisms, and also organs such as liver in humans.
Binary Fission in Bacteria
Budding in Yeast page 164
Budding in Hydra fresh water animals, few millimeters long
Regeneration type of asexual reproduction
anaphase end of cytokinesis interphase Mitosis metaphase prophase telophase