chapters 10 and 11: cell growth and division mitosis/meiosis/cancer
TRANSCRIPT
Chapters 10 and 11:Cell Growth and Division
Mitosis/Meiosis/Cancer
Why is it necessary for cells to divide? DNA Overload-not enough information for
the cell as it grows larger in size To improve material exchange Volume of cell increases faster than surface
area
What is Cell Division ?
process where a cell divides into two new daughter cells Before cell division takes place, the cell must
copy or replicate its DNA. Each daughter cells gets a complete copy of the
original DNA Cell division has 2 parts
Mitosis: division of nucleus and DNA Cytokinesis: division of cytoplasm and organelles
Chromosomes- condensed form of DNA
Sister chromatids- 1 chromosome and a copy of it “tied” together before the cell divides
Centromere- the chemical “knot” holding sister chromatids together
LABEL THE DIAGRAM IN YOUR NOTES.
Figure 10–4 The Cell Cycle
M phase
G2 phase
S phase
G1 phase
Figure 10–4 The Cell Cycle
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Figure 10–5 Mitosis and Cytokinesis
Prophase-Phase #1 of Mitosis
Longest Phase-50% to 60% of total time to complete mitosis
Chromatin condenses into Chromosomes Centromeres connect sister chromatids Centrioles separate to opposite poles Spindle is organized Nucleolus disappears and nuclear envelope
breaks down.
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Figure 10–5 Mitosis and Cytokinesis
Metaphase-Phase #2 of Mitosis
Centromeres attach to spindle fibers Chromosomes line up across the equator of
the cell-metaphase plate
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Figure 10–5 Mitosis and Cytokinesis
Anaphase-Phase #3 of Mitosis
Sister chromatids separate becoming individual chromosomes and moving to opposite poles of cell
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Figure 10–5 Mitosis and Cytokinesis
Telophase-Phase #4 of Mitosis
Chromosomes disperse into chromatin Nuclear envelope re-forms around each
cluster of chromatin Spindle breaks apart Nucleolus visible in each new daughter
cell
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Figure 10–5 Mitosis and Cytokinesis
Cytokinesis
Division of cytoplasm and organelles Animal Cells: Cleavage Furrow-cell
membrane pinches inward Plant Cells: Cell Plate-develops into
separating membrane (cell wall appears shortly after)
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Figure 10–5 Mitosis and Cytokinesis
Cytokinesis
Prophase
Interphase
Metaphase
Prophase
Anaphase
Telophase
Cancer
Disorder in which some cells lose ability to control growth
Form tumors Carcinogen- cancer causing agent (ex.
Cigarettes, UV radiation from sun)
Regulating the Cell Cycle
Skin Cancer : Melanoma
Asymmetrical, Borders, Color, Diameter, Elevation
Meiosis
Cell Division to produce gametes-sex cells (sperm and egg)
Number of chromosomes per cell is cut in half through separation of homologous chromosomes in diploid cell
Homologous Chromosomes
Chromosomes containing same genes 1 chromosome from mom and 1 chromosome
from dad Diploid=2N-cell that has both copies meaning 2
complete sets of genes/chromosomes (all regular cells-somatic cells) In humans 2n=46
Haploid=N-cell that has one set/copy (gametes/sex cells) In humans n=23
Crossing over occurs during Prophase I, and homologous chromosomes exchange portions of their chromatids (DNA)
Meiosis I
Section 11-4
Figure 11-15 Meiosis
Meiosis I
Section 11-4
Figure 11-15 Meiosis
Meiosis I
Meiosis I
Section 11-4
Figure 11-15 Meiosis
Meiosis I
Section 11-4
Figure 11-15 Meiosis
Meiosis I
Section 11-4
Figure 11-15 Meiosis
Meiosis I
Meiosis II
Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a similar way to the metaphase stage of mitosis.
The sister chromatids separate and move toward opposite ends of the cell.
Meiosis II results in four haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
Meiosis II
Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a similar way to the metaphase stage of mitosis.
The sister chromatids separate and move toward opposite ends of the cell.
Meiosis II results in four haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
Meiosis II
Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a similar way to the metaphase stage of mitosis.
The sister chromatids separate and move toward opposite ends of the cell.
Meiosis II results in four haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
Meiosis II
Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a similar way to the metaphase stage of mitosis.
The sister chromatids separate and move toward opposite ends of the cell.
Meiosis II results in four haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
Meiosis II
Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original.
Prophase II Metaphase II Anaphase II Telophase IIThe chromosomes line up in a similar way to the metaphase stage of mitosis.
The sister chromatids separate and move toward opposite ends of the cell.
Meiosis II results in four haploid (N) daughter cells.
Section 11-4
Figure 11-17 Meiosis II
Gamete Formation
In males4 sperm cells are produced In females1 egg cell is produced
Other 3 cells=polar bodies-not involved in reproduction and eventually degenerate b/c do not receive enough cytoplasm containing nutrients
Mitosis Meiosis
Results in production of 2 genetically identical diploid cells
Creates all cells in the body EXCEPT gametes
PMAT
Results in production of 4 genetically different haploid cells
Creates gametes Reason why everyone is
slightly different EXCEPT for identical twins/triplets
PMAT x2 Tetrads form and crossing
over happens