4. cell division
description
Transcript of 4. cell division
![Page 1: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/1.jpg)
I. GENERAL
A. REVIEW DNA1. NUCLEOTIDE
2. DOUBLE HELIX – two nucleotide chains
C-G A-T
![Page 2: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/2.jpg)
II. CELL CYCLE
A. GENERAL
1. DIAGRAM
G1
S
G2
MITOSIS
![Page 3: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/3.jpg)
2. DEFINITIONS
a. DNA – A double helix molecule polymer with geneticinformation.
b. GENE – A segment of DNA that codes for a specifictrait.
c. CHROMATIN – Uncondensed structures made ofDNA & proteins found in the nucleus withgenes on it.
![Page 4: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/4.jpg)
d. CHROMOSOME – A condensed structure of DNA &
proteins found in the nucleus with genes on it.
1 chromosome
1 chromatid = a single DNA molec.1 chromosome
2 chromatids = two DNA molec.
Gene 1
Gene 2
Gene 3
![Page 5: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/5.jpg)
e. DIPLOID – An individual (cell, etc.) has 1 pair of chromosomes with the same genes. The chromosomes can have 1 or 2 chromatids each.
or
f. HAPLOID – An individual (cell, etc.) has 1 chromosome with specific genes. The chromosome can have 1 or 2 chromatids each.
or
![Page 6: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/6.jpg)
g. HOMOLOGOUS PAIR – two chromosomes in a single cell that have the same genes. Found in diploid organisms.
Homologous pair where the chromosomes of the pair have only one chromatid.
Homologous pair where the chromosomes of the pair have two chromatids.
![Page 7: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/7.jpg)
B. PROKARYOTIC CELL DIVISION
BINARY FISSION
![Page 8: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/8.jpg)
C. EUKARYOTIC CELL CYCLE
C1. INTERPHASE
– 90% cell life
– Where the cell spends most of its life
![Page 9: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/9.jpg)
C2. CELL DIVISION (2 TYPES)
MITOSISMEIOSIS
1. DIVIDE
2. # TIMES 1 2
3. WHERE (humans = all cells) (humans=gonads)
4. FUNCTION replace old cells sexual reproductiongrowthasexual reproduction
Mother cell Daughter cells
![Page 10: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/10.jpg)
Interphase
![Page 11: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/11.jpg)
MITOSIS
A. PHASES – diploid organism
prophase
metaphase
anaphase
telophase & cytokinesis
![Page 12: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/12.jpg)
Prophase1. Chromatin into chromosomes
2. Nuclear envelope disintegrates
3. Spindle fibers form near the nucleus and some attach to kinetochores
4. Centrioles start to
move to opposite poles.
![Page 13: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/13.jpg)
Metaphase
Chromosomes line up along the equator.
![Page 14: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/14.jpg)
AnaphaseThe spindle fibers are shortened at the kinetochore which
causes the chromatids to be pulled apart and moved to
opposite poles.
![Page 15: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/15.jpg)
TelophaseChromatids are at opposite poles, start to reform nuclear
membrane, spindle fibers start to disappear.
![Page 16: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/16.jpg)
CYTOKINESISIn animal cells the membrane pinches off to form 2 new
cells, reform chromatin and nucleus .
![Page 17: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/17.jpg)
Overall
![Page 18: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/18.jpg)
III. MEIOSIS - general
Two cell divisions where the resulting
daughter cells have ½ the number of
chromosomes as the originals.
46
23
23
23
23
23
23
MI MII
![Page 19: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/19.jpg)
Prophase I of Meiosis I
Nuclear membrane starts to disintegrate.
Chromatin to chromosomes. Centrioles move. Form spindle fibers.
Homologous Pairs form chiasma where can get
crossing-over (exchange of genetic material) = recombination
![Page 20: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/20.jpg)
Metaphase I of Meiosis IHomologous pairs line up along the equator.
Independent Assortment – the chromosomes arrange themselves independent of the other homologous pairs.
Type of recombination.
![Page 21: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/21.jpg)
Anaphase I of Meiosis I
The spindle fibers shorten and pull apart the chromosomes
of the homologous pairs.
![Page 22: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/22.jpg)
Telophase I of Meiosis I
The chromosomes reach opposite poles and start to form nuclear membrane and disintegrate spindle fibers.
![Page 23: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/23.jpg)
Cytokinesis
Divide cell contents.
The two new cells each contain ½ the number of chromosomes as the original cell (each chromosome has two chromatids).
The chromosomes reach opposite poles and start to form nuclear membrane and disintegrate spindle fibers.
![Page 24: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/24.jpg)
Prophase of Meiosis II
Re-condense chromosomes if they uncondensed and
replicate the centrioles.
Spindle fibers form and centrioles move to opposite poles.
![Page 25: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/25.jpg)
Metaphase of Meiosis II
Chromosomes line up along equator.
Spindle fibers attached.
![Page 26: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/26.jpg)
Anaphase of Meiosis II
Spindle fibers exert force to pull chromatids apart.
![Page 27: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/27.jpg)
Telophase of Meiosis II
Chromosomes reach the opposite poles and start to reform nuclear membranes.
![Page 28: 4. cell division](https://reader033.fdocuments.us/reader033/viewer/2022061213/54970037b47959c06d8b467a/html5/thumbnails/28.jpg)
CytokinesisSplit the cell contents so that end up with four haploid cells.