Asexual Reproduction Mitosis 3 Questions will be asked in 3 minutes. Write a brief answer for each one. Be prepared to share your answer. Mitosis 1
3:00 Mitosis is the process in which the nucleus divides to form two new nuclei. How does mitosis differ in plants and animals?
2:00 WHY DO CELLS DIVIDE? Give me 2 reasons.
HOW will YOU remember IPMAT? 1:00 HOW will YOU remember IPMAT?
TIME’s UP!
Genetics: Mitotic Cell Division
How do little elephants grow up to be BIG elephants?
Why do animals shed their skin?
The process of asexual reproduction begins after a sperm fertilizes an egg.
Where it all began… You started as a cell smaller than a period at the end of a sentence…
And now look at you… How did you get from there to here?
Three reasons why cells reproduce by asexual reproduction: 1. Growth 2 Three reasons why cells reproduce by asexual reproduction: 1. Growth 2. Repair 3. Replacement Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun. Cells that reproduce by asexual reproduction reproduce constantly.
BUT FIRST…. 2)Draw a chromatid. Use your book and define the following terms in your notes. You have 5 minutes. 1) Page 244 CHROMOSOME (it is not in bold, so read carefully) CHROMATID 2)Draw a chromatid. 3) Page 245 CENTROMERE 4) Page 247 SPINDLE
Chromosomes Strands of DNA Each human has 23 pair (diploid or 2n) One from your mother One from your father
Chromosome DNA molecule with attached proteins Sister chromatids One from Mom One from Dad
Chromosome number Every organism has its own specific number of chromosomes Examples: Human = 46 chromosomes or 23 pairs Dog = 78 chromosomes or 39 pairs Goldfish = 94 chromosomes or 47 pairs Lettuce = 18 chromosomes or 9 pairs
Phases and Sub-phases of Cell Division a. G1 1. Interphase b. S c. G2 1. Prophase Nuclear division 2. Metaphase 3. Anaphase 2. Mitosis 4. Telophase b. Cytokinesis From the Virtual Cell Biology Classroom on ScienceProfOnline.com
Control of the Cell Cycle
Interphase Prior & After Mitosis G1 period S period G2 period 90% of cell life spent here Cell goes about it’s business S period DNA is duplicated G2 period Cell prepares to divide Cannot see DNA- uncoiled as chromatin
Animated Mitosis Cycle Interphase Prophase Metaphase Anaphase Telophase & Cytokinesis
Interphase occurs before mitosis begins Chromosomes are duplicated (# doubles) Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase Cells are usually in interphase CELL MEMBRANE Nucleus Cytoplasm
Interphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Prophase 1st step in Mitosis Mitosis begins (cell begins to divide) Centrioles (or poles) appear and begin to move to opposite end of the cell. Spindle fibers form between the poles. Chromosomes coil up and become visible, thicker, and shorter Nuclear envelope disappears Centrioles Spindle fibers
Prophase 1st step in Mitosis Plant Cell Animal Cell Spindle fibers Centrioles Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Metaphase 2nd step in Mitosis Metaphase = Middle Chromosomes attach to the spindle fibers. Chromosomes move to the middle of the cell.
Metaphase 2nd step in Mitosis Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Anaphase 3rd step in Mitosis Chromosomes separate and begin to move to opposite ends of the cell. Spindle fibers pull chromosomes to opposite poles
Anaphase 3rd step in Mitosis Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Telophase 4th step in Mitosis Chromosomes uncoil and appear as threads rather than rods. Nuclear membrane reforms around chromosomes. Two new nuclei form. Spindle fibers disappear Mitosis ends.
Telophase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Cytokinesis occurs after mitosis Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes. Cytoplasm divides. After mitosis and cytokinesis, the cell returns to Interphase to continue to grow and perform regular cell activities
Animal Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase
Plant Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase
Summary of Mitosis Prophase: Metaphase Anaphase Telophase Chromosomes condense Nuclear envelope disappears centrosomes move to opposite sides of the cell Spindle forms and attaches to centromeres on the chromosomes Metaphase Chromosomes lined up on equator of spindle centrosomes at opposite ends of cell Anaphase Centromeres divide: each 2-chromatid chromosome becomes two 1-chromatid chromosomes Chromosomes pulled to opposite poles by the spindle Telophase Chromosomes de-condense Nuclear envelope reappears Cytokinesis: the cytoplasm is divided into 2 cells
Chromosome Appearance & Location Phase Chromosome Appearance & Location Important Events Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
Chromosome Appearance & Location Phase Chromosome Appearance & Location Important Events Interphase Prophase Metaphase Anaphase Telophase Cytokinesis DNA replication, cell grows and replicates organelles DNA copies itself; chromatin Nuclear envelope disappears, spindle fibers form Chromosomes coil up Chromosomes line up in the middle Spindle fibers connect to chromosomes Spindle fibers pull chromosome copies apart to opposite poles Chromosome copies divide and move apart Nuclear envelopes reform, 2 new nuclei are formed, spindle fibers disappear Chromosomes uncoil back into chromatin Division of the rest of the cell: cytoplasm and organelles Chromatin
Cell Cycle
COOL LINKS Mitosis Animation http://www.youtube.com/watch?v=m73i1Zk8EA0&feature=youtube_gdata_player http://www.youtube.com/watch?v=DD3IQknCEdc&feature=youtube_gdata_player http://www.youtube.com/watch?v=XSKh-GLQn4E&feature=youtube_gdata_player http://www.youtube.com/watch?v=eTvaGPcYNF8&feature=youtube_gdata_player