Figure 12.0 Mitosis. Homologous chromosomes Figure 12.4 The cell cycle.
Chromosomes, The Cell Cycle and Mitosis
description
Transcript of Chromosomes, The Cell Cycle and Mitosis
![Page 1: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/1.jpg)
Chromosomes, The Cell Cycle and Mitosis
Cells
Chromosomes
Genes
DNAOrganism
Nucleus
![Page 2: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/2.jpg)
Chromosome
A structure that forms when DNA wraps around proteins and coils up.
Chromosomes only form right before the cell is going to divide.
![Page 3: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/3.jpg)
Each half of a chromosome is called a chromatid. Sister chromatids are
identical to each other. Chromatids are joined at a
centromere. Gene: Segment of DNA
found on a chromosome. Each gene codes for a
specific traits. Each chromosome has
many genes on it.
Chromosome Structure
![Page 4: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/4.jpg)
Two Types of Chromosomes Autosomes- chromosomes that do not
help determine the gender of the individual (most of the chromosomes in your body)
Sex Chromosomes- in humans, they are X and Y; they determine the gender of the individualXX = FemaleXY = Male
![Page 5: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/5.jpg)
Two types of Cells
Gametes- the reproductive cells (sperm for males, eggs for females).
Somatic Cells- all of the cells in the body that are not gametes.Ex – skin cells, muscle cells, brain cells
![Page 6: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/6.jpg)
Chromosome Number in Cells
Different cells can have different numbers of chromosomes depending on where in the body they are located.
Diploid VS HaploidDiploid (2N)– two sets of chromosomes
(one from mom, one from dad) • Somatic cells are diploid
Haploid (N or 1N)– one set of chromosomes
• Gamete cells are haploid
![Page 7: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/7.jpg)
Different organisms have different #’s of chromosomes.Ex: Drosophila melanogaster (fruit flies) : 8 Homo Sapiens (human): 46 Podocnemis uuiilis (turtle): 28
![Page 8: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/8.jpg)
Karyotype - A karyotype is a picture of all of the chromosomes in the cell of an individual, taken right before the cell divides.
Humans: 22 Pairs of Autosomes, 1 Pair of Sex Chromosomes
Homologous Chromosomes
![Page 9: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/9.jpg)
Disorder Activity with Questions
What notation would you use to characterize each disorder?
Is this disorder an autosomal or sex chromosome disorder?
How many chromosomes does a person have with each disorder?
![Page 10: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/10.jpg)
MUTATIONS
Point Mutations (occur in the DNA on the genes)
A. Addition – adding on of extra genes• A B C D A B B C D
B. Deletion – substraction of genes• A B C D A C D
C. Substitution – a different is gene is put in place• A B C D A B F D
D. Translocation – genes are switched around• A B C D C D A B
![Page 11: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/11.jpg)
Chromosomal Mutations (occur in the genes on the chromosome)
MUTATIONS
Some genetic disorders are characterized by having too many or too few chromosomes.
![Page 12: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/12.jpg)
Trisomy 21 Also known as “Down’s Syndrome”
Characterized as having an extra chromosome on the 21st pair.
Affects approximately 800 in 1,000
births
Maternal Age Risk at birth 15 to 24 years 1 out of 1300 25 to 29 years 1 out of 1100 35 years 1 out of 350 40 years 1 out of 100 45 (and older) 1 out of 25
![Page 13: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/13.jpg)
Klinefelter’s Syndrome Characterized as a male with an extra “X” chromosome (XXY) The condition exists in roughly 1 out of every 500 to 1,000 males Extra “X” causes slight feminization
(including small penis, tall physique, enlarged breast tissue and
infertility)
![Page 14: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/14.jpg)
Turner Syndrome Characterized as a female with only one “X” chromosome (XO) Turner syndrome occurs in about 1 out of 2,000 live births Symptoms include webbed neck, drooping eyelids, short height
and infertility
![Page 15: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/15.jpg)
THE CELL CYCLE
All somatic cells undergo the cell cycle in order to prepare for cell division (mitosis)
Mitosis is a form of asexual reproduction. The cells that form as a result of mitosis are clones (identical copies) of the original cell.
Why do our cells need to divide????
1. Growth of the organism
2. Repair of cells or replacement of “dead” cells
![Page 16: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/16.jpg)
Stages of the Cell Cycle
G1 PhaseS PhaseG2 PhaseMitosisCytokinesis
![Page 17: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/17.jpg)
G1 (growth 1) Phase
First growth stage Cell increases in size
![Page 18: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/18.jpg)
Synthesis (S) Phase
Copying of all DNADNA is replicated
Chromosomes duplicatedChromosomes needs to be copied before a cell divides, so that each new cell has the correct amount of DNA and the correct number of chromosomes.
![Page 19: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/19.jpg)
G2 (growth) Phase
Cell continues growing.
![Page 20: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/20.jpg)
Interphase – Resting Stage
Interphase is the first 3 phases of the cell cycle togetherG1, S and G2
Cells carrying on normal activities Chromosomes aren’t visible (not coiled
up). Normal cell metabolism and processes
are occurring. Occurs before mitosis. Includes phases of
cell cycle “getting ready” for mitosis
![Page 21: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/21.jpg)
Interphase
![Page 22: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/22.jpg)
Mitosis (M) and Cytokinesis Phases
Cell growth & protein production have stopped.
The cells energy is used to make 2 daughter cells (splitting of original cell into 2). Mitosis – division of the nucleus into 2
nuclei in one cell. Cytokinesis – division of cytoplasm,
resulting in 2 new cells.
![Page 23: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/23.jpg)
Cell Cycle CheckpointsThe cell has checkpoints to ensure that each phase was completed correctly.
G1: is the cell big enough
S/G2: did the DNA copied correctly
Mitosis (and Cytokinesis): making sure the cell divided correctly.
Checkpoints not working and the cell dividing uncontrollably can lead to cancer.
![Page 24: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/24.jpg)
Give each student has a copy of the “Understanding Cancer” worksheet from the NIH: Cell Biology and Cancer curriculum guide. This is available online at: http://science.education.nih.gov/supplements/nih1/cancer/guide/pdfs/ACT2M.PDF (To see the entire Cell Biology and Cancer curriculum guide, go to http://science.education.nih.gov/supplements/nih1/cancer/default.htm) Use a computer and projector to show students the 5 animations available online at: http://science.education.nih.gov/supplements/nih1/cancer/activities/activity2_animations.htm
![Page 25: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/25.jpg)
SURVEY
IPAD: Internet CODE: S2013109
GOOGLE: Endicott research center
![Page 26: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/26.jpg)
CANCER
The disease caused by an uncontrolled division of abnormal cells in a part of the body.
A malignant growth or tumor resulting from such a division of cells.
![Page 27: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/27.jpg)
Stages of Mitosis
ProphaseMetaphaseAnaphaseTelophase
![Page 28: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/28.jpg)
PROPHASE DNA coils tightly & becomes
visible as chromosomes. Nuclear membrane
disappears Centrioles migrate to poles
Centrioles: organelles that produce spindle
Spindle fibers begins to form
![Page 29: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/29.jpg)
Prophase -under the microscope
![Page 30: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/30.jpg)
METAPHASE
Spindle fibers from centrioles attach to each chromosome.
Chromosomes line up in the middle of the cell.
![Page 31: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/31.jpg)
Metaphase –under the microscope
![Page 32: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/32.jpg)
ANAPHASE
Chromosomes are already separated into sister chromatids at the centromere.
o Spindle fibers shorten and each chromatid is pulled to the opposite end of cell.
![Page 33: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/33.jpg)
Anaphase –under the microscope
![Page 34: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/34.jpg)
TELOPHASE Separation of chromosomes into
chromatids is completed Nuclear membrane reforms.
Now have two nuclei in one cell Chromosomes uncoil
![Page 35: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/35.jpg)
Telophase – under the microscope
Plant Animal
![Page 36: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/36.jpg)
CYTOKINESIS Cytoplasm division Occurs after chromosomes separate
and two nuclear envelopes reappear. Forms two, identical daughter cells
(they are identical to the original cell)
![Page 37: Chromosomes, The Cell Cycle and Mitosis](https://reader035.fdocuments.in/reader035/viewer/2022062500/5681500e550346895dbdef6e/html5/thumbnails/37.jpg)
Check your chromosome numbers!!!
Human Cell:
Before G1 –
46 chromatids
After S –
92 chromatids (46 chromosome pairs)
After mitosis –
2 cells each with 46 chromatids!!
Daughter cells are identical to the parent cell!!!