Download Cell Cycle

Cell Reproduction
How do cells make new cells?
Cell Reproduction
• Reproduce: process by which living things
give rise to other living things
– Two Types of Cell Reproduction
• Asexual: one parent offspring is identical
• Sexual: two parents offspring is not identical
Types of Asexual Reproduction
• 1-Binary Fission
– Primary way that bacteria (unicellular) cells
reproduce
Binary Fission Clip
• http://www.classzone.com/cz/books/bio_0
7/resources/htmls/animated_biology/unit2/
bio_ch05_0149_ab_fission.html
2-Budding
• Usually seen in yeast cells
• Cell replicates when a piece of the cell
pinches off and separates from the parent
cell
3-Spore
• Found in fungi, algae, protozoa
• Airborne cells that are released from the
parent. They are enclosed and developed
when the environment is appropriate
4-Regeneration
• Ability to re-grow lost parts
• Found in starfish, earthworms, some
reptiles
5-Vegetative Propagation
• Regeneration in plants from an area that is
remaining
6-Mitosis
• The process where animal cells divide
• This is a type of asexual reproduction
• Body cells (somatic cells) go through the
process of mitosis
Sexual Reproduction in cells
• Meiosis
– Process where sex cells are made in the
gonads
• Gonads organs where sex cells are made
– Male testes make and house sperm
– Females ovaries make and house eggs
We will discuss meiosis later!!!!
What structures are mainly in
charge of cell replication?
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Chromosomes are composed of DNA and in charge of replication
Only visible during cell division as X shaped structures.
Humans have 46 chromosomes (23 pairs).
Each X shaped chromosome consists of 2 “sister” chromatids
produced during replication Called DIPLOID 2N
• The “sister” chromatids are attached at an area called the
centromere
Cell Cycle
• Why is the cell cycle called a cycle?
• Why do you think it’s important for a cell to
grow in size during its cell cycle?
Cell Cycle- The Cell’s Timeclock
Cell Cycle- is the series of events that takes
place in a cell leading to its division and
duplication
• http://www.cellsalive.com/mitosis.htm
Interphase: not part of mitosis
• Interphase-(technically not part of mitosis, but it
is included in the cell cycle)
• Cell is in a preparing for mitosis, performing cell
functions
• DNA replicates (copies)
• Organelles double in number, to prepare for
division
– G1 - First growth
– S - synthesis (copy DNA)
– G2 - Second growth
Process of Mitosis
• http://www.neok12.com/php/watch.php?v=
zX5c687103030a0864645802&t=CellDivision
• http://www.johnkyrk.com/mitosis.html
Prophase
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Spindle forms
Centrioles move to opposite poles
Chromosomes become visible
Nuclear membrane breaks down in
prometaphase
Metaphase
• Chromosomes line up along the equator
Anaphase
• Centromeres divide
• Chromatids separate and move to
opposite poles
Telophase
• Nuclear membrane forms around each
group of chromosomes
• Chromosomes unwind, nuclear membrane
forms again
Cytokinesis begins
• Cell pinches inward and forms two
daughter cells
Visit this website
http://www.neok12.com/php/watch.php?v=z
X645478027c03150f647502&t=CellDivision
http://www.johnkyrk.com/mitosis.html
It will show you an animation of mitosis
Results of Mitosis
• Same number of chromosomes from
generation to generation (46 in humans)
• Each daughter cell (offspring) gets exact
copy of chromosomes
Consequences of Incorrect Mitosis
• Cancer: uncontrolled mitotic division in
cells
– Timeclock (cell cycle) does not work properly
http://www.hhmi.org/biointeractive/cancer/angio
genesis.html
Plant Mitosis
• Same process as in animal cell but plants
don’t have the centrioles and a cell plate
forms
Uses for Mitosis
• Replicate young embryonic cells
• Replicate body (somatic) cells. Skin, blood
cells
• Repair damaged cells
• Controls cell growth and death.
– Cytokinins: chemicals that regulate cell
replicating