1 1 asexual reproduction presents: mrs. stewart honors biology: cell growth and division
TRANSCRIPT
STANDARDS CLE 3210.4.2 Describe the
relationships among genes, chromosomes, proteins, and hereditary traits.
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OBJECTIVES Evaluate the reasons for asexual
reproduction in organisms
Differentiate between the different stages of the cell cycle in terms of order of occurrence, and chromosome location
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LET’S REVIEW:CHROMOSOMES
What do they look like?
How many do humans have?
They look like an “X” just before the cell divides and an “I” after they divide.
• 46 (23 pairs)
• (23 from mom, 23 from dad)
CELL DIVISION IN EUKARYOTES
There are two different types of cell division
Which type is performed depends on the kind of “daughter cells” that
are desired
Mitosis = identical daughter cells with same amount of DNA
Meiosis = genetically different daughter cells with half the amount of DNA
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Somatic CellsEvery cell in the body
EXCEPT reproductive cellsHave all 46 chromosomes
GameteSexual reproduction cells
(Example: sperm for males, Ova/eggs for females)
have half the amount DNA (23 chromosomes)
Three reasons why cells reproduce by asexual reproduction:
1. Growth 2. Repair 3. Replacement
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ASEXUAL REPRODUCTION
- REQUIRES ONLY ONE PARENT/CELL
- MAKES SOMATIC CELLS
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At what point does it become necessary for a
cell to divide?
When the cells resources are under too great a strain from it’s size
• Cell Membrane not large enough to maintain needs coming in/going out
• DNA, used for protein synthesis, cant keep up with demands
• Organelles unable to keep up with demands (ie: waste removal)
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CE
LL
CY
CL
E2 Main Stages:
1. Interphasea)G1b)Sc) G2
2. Mitosis – M phasea)Prophaseb)Metaphasec) Anaphased)Telophasee)Cytokinesis
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Create yo
ur g
raph
ic org
anizer
INTERPHASE ANAPHASE
PROPHASE TELOPHASE
METAPHASE CYTOKINESIS
CELL CYCLE
ASSIGNMENT:
Create a mnemonic device to help you remember –
I-P-M-A-T-C
We will vote on the best one tomorrow in class. Winner gets a two day “slack” pass.
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ANIMATION Mitosis animation – mcgraw-hill
Cell cycle animation – cells alive website
Mitosis – sumanas (step by step w/ tutorial and quiz)
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Interp
hase
• Time between cell divisions• 90% of a cell’s life
3 phases:1. G1: Growth and everyday
activities
2. S: DNA replication
3. G2: preparation for Mitosis (production of necessary proteins/organelles)
The process of dividing the nucleus
to create two daughter cells, identical to the
mother cell
Mitosis
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Mitosis• Creates two daughter cells that are
identical to each other AND identical to the parent cell
• Creates diploid cells (two sets of chromosomes in each daughter cell)
• Allows organisms to grow• Allows organisms to replace
damaged/worn out cells• P-M-A-T-C
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PR
OP
HA
SE
•The DNA (chromatin) organizes into chromosomes
•The nuclear membrane disappears
•Centrosomes (centrioles) move to opposite ends of cell
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ME
TAP
HA
SE
Chromosomes attach to spindle fibers (by their centromeres), and line up at the center of the cell
Spindle Fibers – microtubules that help separate chromosomes during division
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AN
AP
HA
SE
Chromosomes separate at the
centromere, and the sister chromatids are
pulled toward opposite ends of the cell.
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CY
TO
KIN
ES
IS
The division of the cell cytoplasm, usually beginning during Telophase and finalizing the production of two new daughter cells.
Each new cell will have about ½ of the cytoplasm and organelles of the parent cell.
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CLEAVAGE FURROW VS.
CELL PLATE
ANIMAL
Cleavage furrow indentation of the cell membrane to form two separate
cells
Plants
Cell plate A cell wall is rigid and cannot
flexibly move and pinch together to separate the newly formed cells. So, a cell plate forms
between the two new cells. This cell plate will harden and become
a cell wall for each.
CY
TO
KIN
ES
IS
REMEMBER:
Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
I PLAY MUSIC AT THE CLUB11/01/11
I P M A T C