Post on 27-Dec-2015
Cell Cycle2 main parts
Interphase- Cell is normal
Mitosis- Cell is dividingCytokinesis- occurs at the end of mitosis
MitosisDivides DNA into 2 nucleiMakes 2 daughter cells with a diploid number
Used for growth and repair
Also used in some asexual reproduction
Stages of Mitosis (P-M-A-T)
Interphase Early Prophase
Metaphase
Early Anaphase
Prophase
AnaphaseTelophase
http://micro.magnet.fsu.edu/micro/gallery/mitosis/mitosis.html
Prophase
DNA condensesNuclear envelope dissolves
Spindle fibers start to form
Prophase(in animal cell and onion cell)
MetaphaseChromosomes align in the middle of the cell (equator)
Spindle fibers attach to the chromosomes to move them
AnaphaseChromosomes separate to opposite poles
Spindle fibers split chromosomes in half
Telophase 2 nuclear envelopes form
around the separated DNA Spindle fibers dissolve In animal cells
Cell membrane pinches in In plant cells
Cell plate forms which later becomes 2 cell walls
Cytokinesis
Cytoplasm and organelles divide
2 cells form
http://www.classzone.com/cz/books/bio_07/get_chapter_group.htm?cin=2&rg=animated_biology&at=animated_biology&var=animated_biology
Animation of Stages of Mitosis
http://biology.about.com/library/blmitosisanim.htm
Binary FissionAsexual reproduction for bacteria
DNA is copied in 1 cellThe cell divides into 2 cells with the same DNA
http://www.classzone.com/cz/books/bio_07/get_chapter_group.htm?cin=2&rg=animated_biology&at=animated_biology&var=animated_biology
Somatic cellsBody cellsAll cells not involved in
reproductionDiploid cells (2N)
Contains 2 copies of each chromosome
In humans 46 chromosomes
Made by mitosis
Gametes Sex cells Egg (female) or sperm (male) Haploid cells (1N)
Contains 1 copy of each chromosome
In humans 23 chromosomes Made by meiosis Used in sexual reproduction
Sexual Reproduction
Offspring are a mixture of both parents
Occurs by meiosis then fertilization Meiosis
Formation of gametesMakes haploid cells from diploid
cells Fertilization
The actual fusion of the 2 gametesFirst cell is called a zygote
Asexual Reproduction
Sexual Reproduction
advantages 1 parent, requires less energy, fast
Increases genetic diversity, increasing the ability to adapt
disadvantages Decreases genetic diversity,Less likely to adapt
2 parents, requires more energy, slow
Meiosis
Process of making gametes for sexual reproduction
Events that occur during meiosis allows for greater genetic diversity
Meiosis Meiosis I
Makes 2 unique diploid cellsProphase I – Telophase I
Interphase without duplicating DNA
Meiosis IIMakes 4 unique haploid cellsProphase II – Telophase II
Crossing OverOccurs in Prophase I
Homologous chromosomes line up and sections of the chromosomes overlap and become incorporated into the other
Allows for genetic diversity
Independent AssortmentOccurs in Metaphase I Independent Assortment
Allows for genetic variationWhen homologous
chromosomes line up in the middle, some chromosomes from the mother and father line up on either side