this cartoon is describing? mitosis: cell...
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Mitosis: Cell Division
Key Points On Cell Division
� Species must reproduce in order to survive from generation to generation.
� All living things reproduce by cells dividing called cell division.
� Cell division allows for growth and reproduction.
� Also, helps to replace old and damaged cells.
� To maintain the surface area for the given volumeof each cell’s growth. Ex: a balloon
Cell Division: A Basic Fact of Life
Every living creature from
bacterium
to whales
and to trees
results from cell division!
Mitosis� Two types of cell division are mitosis & meiosis.
� In mitosis, body cells called somatic cells go through cell division. These cells are nonsex cells.
� The uncontrollable cell division of certain abnormal
cell is referred to as cancer.
Mitosis (mitotic cell division)
� Mitosis is a series of changes in the nuclei of all body cells.
� Therefore, reproduction occurs in the nucleus.
� Chromosomes replicate then parent cell divides.
� Parent divides into 2 daughter cells.
� Both daughter cells have the same # of chromosomes as the parent.
� The number of chromosomes is 46 (2n).
2
46
46 46
2 Daughter Cells
2N
2N 2N
DNA
replication
Mitosis
2 Diploid daughter cells
46Chromosomes
46
46
46 46
46 Words To Know
� Nucleus
� Chromatin
� Chromosomes
� Centrioles
� Centromeres
� Poles
� Spindle fibers
� Equatorial plate
� Cytokinesis
� Nucleus- Contains hereditary material called
chromosomes.
� Chromatin- Thin twisted threads made of DNA. - Found during non-dividing cells.
� Chromosomes- Thickened & coiled chromosome made of DNA
- Found during dividing cells (mitosis).
Genetic Material In Mitosis
Replicated
Chromosome
2 Chromatidseach with a double helix
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Replicated Chromosome
2 Chromatids each with a double helix
http://bcs.whfreeman.com/thelifewire/content/chp11/1102002.html
Structures seen during Mitosis
� Centrioles- Two tiny football shaped bodies that make
spindle fibers to pull double chromosome apart.
� Centromere (button)- Connect the chromatids in the center.
Draw &
Label A.
B.C.
� Poles
- The opposite ends of the cell.
� Spindles fibers
- Fibers that help move chromosomes during cell division. Spindle
Poles
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Equatorial plate
� Region where the chromatids reach the center of the cell.
Equatorial
Plate
Cytokinesis
- Cytoplasm divides into two parts.
- Each part has its’ own nuclei & a
complete set of hereditary material
(DNA).
The Process of Cytokinesis
Cleavage- the tightening and
pulling of protein
Nucleus
Microtubules
The Cell Cycle
What Does “Cell Cycle” Mean?
� The repetitive process that cells undergo
for cellular growth and reproduction.
� Cell cycle has 2 phases.
Interphase Mitosis
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� Different cells vary in the time they spend in interphase and mitosis.
Ex: Nerve cells can spend up to 60 years in
interphase and so rarely reproduce. This is why spinal cord injuries and stroke patients have permanent damage.
Nerve Cells Cancer Cells
� Cancer cells are never
at rest and remain a short time in interphase
and so cells
keep dividing.
Cell Cycle: Interphase + Mitosis
� A human cell can divide (go through mitosis) in 1 hour.
� Cells in the interphase period can remain for 16-20 hours.
Cell is synthesizing its structural proteins and enzymes
chromosome is copied to be 92.
Or each
Prepares for mitosis
The Phases of Mitosis
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
“PMAT”
Cell Cycle: Interphase + Mitosis
� Interphase is not considered part of mitosis(division stage).
� Interphase is the period before mitosis
begins.
Mitosis and Cell Reproduction
Looking At The Cellular
Level
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The Phases of Mitosis
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
Cytokinesis
“PMATc”Let’s Draw The
Phases of Mitosis
Use Board
Interphase &
Mitosis In
Animal Cells
46
Chromosomes
4646
Chromosomes
Doubled to 92
Middle
Apart
Interphase � Chromosomes long,
thin, thread-like & not visible in the nucleus.
� Uncoiled DNA is called chromatin. Each makes a copy of
itself (replication).
� Centrioles form.
http://www.cellsalive.com/cell_cycle.htm
Prophase� Chromosomes thicken
& can see under microscope.
� Nuclear membranedisappears.
� Spindle fibers form.
� Centrioles move to opposite sides.
� Centromeres holdchromosomes together.
ChromatidsCentromere
CentriolesSpindle
fibers
Metaphase
� M = MIDDLE
� Double chromosomes
line up in the middle
of the cell by the spindle fibers.
Metaphase plate
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Anaphase
� Spindle fibers
shorten & pull apart(separate).
� Chromatids become
single-stranded
chromosomes as they
move to opposite sides.
Telophase &Cytokinesis
Telophase� Chromosomes uncoil
into chromatin.
� Nucleolus & nuclear membraneform again.
Cytokinesis- Pinching of the cell &
cytoplasm divides.
� Two new daughtercells form & each is identical to the original.
46
46
The first stage of mitosis when chromosomes
start becoming visible in the microscopeis called:
A. anaphase
B. prophase
C. telophase
D. metaphase
Prior to cell division, each chromosome replicates or duplicates its genetic material. The products are
connected by a centromere and are called:
A. sister chromosomes
B.homologous
chromosomes
C. sex chromosomes
D. sister chromatids
Which of the following statements is
NOT true of mitosis?
A.
A single nucleus gives rise to two identical daughter nuclei.
B
.The daughter nuclei are genetically identical to the parent nucleus.
C
.The centromeres divide at the onset of anaphase.
D
.Homologous chromosomes synapse in prophase.
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MitosisIn Plant Cells
Plant Cells
�Mitosis can be seen in developing seeds, the roots, and stems.
�Same nuclear division occurs in
both plant cells and animal cells.
How Does Mitosis Differ In Plants?
1. No centrioles.
2. A cell plate forms between 2 daughter cells. So no pinching
occurs.
Cell Plate
No Centrioles
Which of the following features of cell division
are very different for animal and plant cells?
A. prophase
B. metaphase
C. anaphase
D. cytokinesis