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The cell is going to divide!!??. www.bioweb.uncc.edu/biol1110/stages.htm www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/cells1.html science.nhmccd.edu/biol/mitosis/pmitosis.html. Levels of Organization. Cell (animal or plant; Body or sex cell)
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www.bioweb.uncc.edu/biol1110/stages.htm • www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/cells1.html • science.nhmccd.edu/biol/mitosis/pmitosis.html
Levels of Organization Cell (animal or plant; Body or sex cell) Nucleus (Contains chromosomes) Chromosomes (divide during cell division) Gene (Segment of Chromosome) DNA (Contains genetic information)
Vocabulary • Gamete: sex cells= sperm or egg • Fusion of gametes forms a zygote. • A zygote always has a full or diploid (2n) number of chromosomes
Each species has a characteristic number of chromosomes. • Diploid (2n) number includes two sets of chromosomes of each type. • Found in all the non-sex cells or autosomes of an organism's body (with a few exceptions). • Examples include humans (46), crayfish (200), etc. • Haploid (n) numbercontains one of each kind of chromosome. • In the life cycle of many animals, only sperm and egg cells(sex cells) have the haploid number. • Examples include humans (23), crayfish (100), etc.
Types of Chromosomes: • Autosomes = Body chromosomes or non sex chromosomes ( humans have 44 or 22 pairs) • Sex Chromosomes = XX or XY (23rd pair for humans) determines the sex of the offspring
Mitosis:the division of body cells **Daughter cells are identical to Parent cell Parentcell 46 chromosomes Daughter cell 46 chromosomes Daughter cell 46 chromosomes
Remember Cell size? 1cm • If your cells Were this size Then
THE CELL CYCLE *Interphase *Mitosis *Cytokinesis
Interphase • *Time in between cell division (mitosis) • G1= Cell growth • S = DNA Replication • G2 = Prep for mitosis
Prophase Centromeres produce spindle fibers 1. Chromosomes appear condensed 2. Nuclear envelope and nucleus disappears 3. Centrioles separate to the poles of the cell 4. Chromosome (at their centromeres)attach to spindle fibers
Metaphase 1. Chromosomes line up in the equator (center) of the cell. (Spindle fibers help move chromosomes thru cell)
Anaphase 1. The centromere splits and chromatids separate. 2. Chromatids move to the poles of the cell
Telophase 1. Chromatids start to become diffuse (chromatin) 2. The nuclear envelope starts to reform 3. Nucleolus reforms 4. Spindle breaks apart 5. Cells begins splitting
Cytokinesis * NOT a phase of mitosis • It is a process of the cytoplasm dividing after mitosis.
Interphase • *2 new cells are formed • *Identical to the original parent cell
THE CELL CYCLE *Interphase *Mitosis *Cytokinesis
Plant Mitosis Onion Root Tip Cells
Cell Division: Prokaryotes • The Prokaryotic Chromosome • Chromosome consists of nucleoid (an irregularly-shaped region, electron-dense, and not enclosed by a membrane. • Chromosome, when stretched out, is a circular loop attached to the inside of the plasma membrane; about 1,000 times the length of the cell.
3. When cell is approximately twice its original length, the plasma membrane grows inward, a new cell wall forms dividing the cell into two approximately equal daughter cells. • 4. Generation times of Escherichia coli is 20 minutes; most bacteria need up to one hour to a day.