Cell Division
-
Upload
amos-roberts -
Category
Documents
-
view
16 -
download
0
description
Transcript of Cell Division
![Page 1: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/1.jpg)
Cell Division
![Page 2: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/2.jpg)
Why Cells Make More Cells1. Most cells go through a series of changes in order
to maintain homeostasis.2. Cells need to reproduce (divide) when their surface area
can no longer supply the much larger volume with nutrients and get rid of wastes.
Surface Area (length x width x 6)Volume (length x width x height)
Ratio of Surface Area to Volume
![Page 3: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/3.jpg)
Vocabulary
1. Chromatin: the relaxed, uncoiled state of the chromosome
2. Chromatid: one of two identical “sister” parts of a duplicated chromosome
3. Chromosome: threadlike structures within the nucleus containing genetic information that is passed on from generation to generation
4. Centromere: chromosome region that joins 2 sister chromatids
A: centromere
chromo─ color ─soma: body─id: self, body
centro─ center─mere: part
B: chromatids
![Page 4: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/4.jpg)
Chromosomes1. Chromosomes: made up of
DNA & proteins
2. Carry the cell’s coded genetic information
3. Different organisms have a different number of chromosomes
Fruit flies have 8 chromosomes in each
body cell
Frogs have 26 chromosomes in each body cell
Humans have 46 chromosomes in each body cell
![Page 5: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/5.jpg)
Cell Cycle1. Cell cycle: Sequence of events between the time a cell
divides to form 2 daughter cells & the time those 2 cells divide
2. Consists of Interphase and M-phase (Mitosis & Cytokinesis)
3. G0 ─ cells that exit the cell cycle
![Page 6: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/6.jpg)
Interphase: 3 Phases
1. G1 phase: Growth Phase
a. Cell performs all life’s activities: protein synthesis, waste removal, organelle synthesis, etc.
2. S phase: DNA Replication
a. DNA makes a copy of itself
b. Produces 2 identical sets of chromosomes
3. G2 phase: Preparation
a. Cell produces centrioles & spindle fibers needed to move the chromosomes
![Page 7: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/7.jpg)
Mitosis Discovered
Walther Flemming first discovered mitosis in 1870 and reported is discovery of chromosomes and mitosis in 1882.
Metaphase in a salamander celldrawn by Walther Flemming from a stained slide.
![Page 8: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/8.jpg)
Mitosis Review 1. Two main stages of the M-phase
a. Mitosis: division of the nucleus b. Cytokinesis: division of the
cytoplasm2. Produces 2 cells called daughter cells a. Cells are genetically identical3. Mitosis is source of new cells for a. Growth b. Development c. Repair d. Replacement of old cells4. Cells that go through mitosis: skin,
bone, muscle, liver5. Cells that RARELY go through mitosis:
nerve cells
Normal red blood cells only live for 120 days. Then they die & stem cells make new ones.
![Page 9: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/9.jpg)
Mitosis
1. Described as movement of chromosomes
2. Continuous series of events
3. Divided into four phases so that it is easier to understand
Cell Cycle
![Page 10: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/10.jpg)
Diploid verses Haploid Di─ doubleHaplo─ single-oid: like
23Sperm cell
23
Egg cell
46
Fertilized Egg cell
Fertilization
Haploid: 1n; 1 set of chromosomes•The egg and sperm cell are haploid
Diploid: 2n; 2 sets of chromosomes•The fertilized egg cell is diploid
Develops into
All of the cells that make up the organism are diploid
Each kind of cell:•Skin•Muscle•Bone•Nerve
•Are ALL DIPLOID
![Page 11: Cell Division](https://reader030.fdocuments.in/reader030/viewer/2022032612/5681341f550346895d9b0b62/html5/thumbnails/11.jpg)
1. Normal cells contain check points to regulate the cell cycle, & stop at appropriate check points.
2. Cancerous cells do not respond to check points and continue rapidly through the cell cycle. This results in masses of undefined cells called tumors.
3. Cancer cells do not mature; they become more immature.
Do not enter into G0
Cancer Cells