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MITOSIS STUDY GUIDE
KEY
1. Asexual vs Sexual Reproduction:
a. Asexual reproduction: offspring arise from a single organism, and inherit the genes of
that parent only. It does not involve the fusion of egg and sperm.
b. Sexual reproduction: offspring arise from the union of egg and sperm which come from
two parents.
2. Examples of organisms of Asexual and Sexual Reproduction
a. Asexual: bacteria, single-celled eukaryotes like protists and unicellular fungi (binary
fission).
b. Sexual: multi-cellular eukaryotes like insects, reptiles, birds, mammals (dogs, humans)
3. Three reasons why cells undergo mitosis:
a. Cell replacement
b. Growth
c. Asexual reproduction
4. Interphase (G1, S, G2); Mitotic phase (mitosis, cytokinesis); Mitosis (Prophase, Metaphase,
Anaphase, Telophase)
5.
Interphase
Prophase
Metaphase
Anaphase
Telophase
M
6. See micrograph
P
T
7. Interphase Stages:
I
a. G1 (Cell growth)
b. S (DNA replication or synthesis)
c. G2 (Preparation for division:
A
additional proteins and
organelles made)
8. Mitosis phases:
a. Prophase: DNA (chromatin) coils into chromosomes, centrioles move to opposite end of
cell, nuclear membrane breaks down, spindle forms.
b. Metaphase: Chromosomes align in middle of cell, spindle fibers attach to centromeres
of chromosomes, non-attached spindle fibers stretch cell out.
c. Anaphase: Chromatids separate from chromosomes and move along spindle fibers to
opposite end of the cell, cell continues to stretch out.
d. Telophase: Chromatids reach the opposite ends of the cell and unwind back into
chromatin, spindle disappears, nuclear membrane forms around each set of
chromosomes.
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MITOSIS STUDY GUIDE
9. The cytoplasm of the cell divides in two, forming two new daughter cells.
10. Cytokinesis:
a.
Animal cells form a cleavage furrow
b. Plant cells form a cell plate
which then develops into
a cell wall.
11. DNA Packaging
a. In prokaryotes: DNA forms a loop and is not in the form of chromatin (no proteins). It is
referred to as “naked” DNA.
b. In eukaryotes: DNA exists in long, individual strands that wrap around special proteins
called histones, forming chromatin. During cell division, the chromatin condenses into
rod-shaped structures called chromosome
12. Naked DNA vs Chromatin vs Chromosomes:
a. Naked DNA is pure double-stranded DNA
b. Chromatin is DNA wrapped around proteins called histones.
c. Chromosomes can exist in three forms
i. as naked DNA
ii. as chromatin
iii. as a chromatid
13. Chromatid vs centromere vs telomere
a. Chromatid: one of two identical copies of a replicated chromosome.
b. Centromere: an area where two sister chromatids are attached.
c. Telomere: the ends of a chromosome.
14.
Chromatid
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MITOSIS STUDY GUIDE
15.
Telomeres
Centromere
Telomeres
16. Cells must replicate their DNA prior to mitosis so that each new daughter cell will have a
complete set of chromosomes.
17. Centrioles help to organize the spindle fibers during mitosis.
18. Spindle fibers have two functions
a. they stretch the cell during mitosis
b. they attach to the centromeres of chromosomes and guide the chromosomes to
opposite ends of the cell during anaphase.
19. Two identical daughter cells are produced as a result of mitosis.
20. A newly formed mitotic daughter cell has the same number of chromosomes as the parent cell.
21. Human cells contain 46 chromosomes, 23 inherited from mom and 23 from dad.
22. Stem cells
a. Totipotent: Cells that can differentiate into any type of cell and can give rise to an entire
organism. Obtained from 1-4 day old embryos.
b. Pluripotent: Cells that can develop into all types of body cells, except the cells that form
the tissues that surround the embryo. They cannot give rise to an entire organism.
Obtained from in embryos.
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MITOSIS STUDY GUIDE
c. Multipotent: Cells that can produce many, but not all types of differentiated cells within
a given organ. For example, mesenchymal stem cells can develop into bone, cartilage,
muscle, skin, adipose (fat). Obtained from stem cells in the organs of adults (brain,
teeth, skin, heart, gut, muscle, liver, blood vessels, cartilage, nerves, bone, etc.)
23. As the size of a cell decreases, its surface area-to-volume ratio increases. The larger the surface
area-to-volume ratio, the more efficient a cell can “feed” itself and remove wastes.
24. Calculating surface area-to-volume ratio of a cube
a. Surface area = L x W x 6
b. Volume = L x W x H
c. Ratio = Surface area / volume
25. Regulatory proteins
a. External regulators: Growth factors
i. Control cell cycle for injuries and broken bones
ii. Control cell cycle for growth of an embryo
b. Internal regulators: Cyclins
i. Control DNA replication during S phase of Interphase.
ii. Control timing of the cell cycle.
26. Apoptosis is a process in which a cell is programmed to die. As an embryo develops, the tissue
between the fingers is programmed to die. The cells that remain form the fingers. The outer
layer of skin on a person is made of dead cells and is constantly being shed from the body.
Under the dead layer are living skin cells. As the outer dead layer is shed, newly formed cells are
programmed to die to replace them.
27. Cancer is caused by uncontrolled cell growth. Cancer cells divide without control because they
do not respond to the signals that regulate the cell cycle. Certain chemicals (phosphates),
tobacco smoke, radiation exposure, viral infections (HPV), and chance mutations in DNA are all
known to cause cancer.
28. Treatments include chemotherapy, surgery, and radiation.
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MITOSIS STUDY GUIDE
29. Gametes are sex cells, like egg and sperm. An embryo is an unborn or unhatched offspring.
30. Cell differentiation is a process in which cells become specialized in structure and function.
For example, a blood stem cell can give rise to the following types:
-red blood cells
-white blood cells (of which there are 5 different types)
-platelets
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