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Mitosis/Meiosis. How do your cells divide?. A few words before we start…. Haploid: Diploid:. Interphase. A Cell’s Life. Why Do Cells Divide?. Surface area. Damaged cells. Sex cells. Cell Reproduction. is either sexual or asexual. Asexual Reproduction (one parent). Binary Fission-
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Mitosis/Meiosis How do your cells divide?
A few words before we start….. • Haploid: • Diploid:
Interphase A Cell’s Life
Why Do Cells Divide? Surface area Damaged cells Sex cells
CellReproduction is either sexual or asexual
Asexual Reproduction(one parent) • Binary Fission- • Budding • Vegetative Propagation • Regeneration
Advantages of Asexual Reproduction Speed Replacement Desirable Characteristics
DNA Replication • Before a cell can divide the DNA must replicate (make a copy of itself)
DNA Replication • Making a new strand of DNA is actually quite easy. • Replication occurs in 3 easy steps…
1. DNA Unzips • An enzyme unzips the molecule • The enzymes breaks the hydrogen bonds that hold the nitrogen bases together.
T A C G C G DNA Replication DNA Unzips
T A C G C G DNA Replication DNA Unzips
T A C G C G DNA Replication DNA Unzips
T A C G C G DNA Replication DNA Unzips
T A C G C G DNA Replication DNA Unzips
T A C G C G DNA Replication DNA Unzips Left Strand of Original DNA Right Strand of Original DNA
2. Base Pairing • Complementary bases match with each DNA strand in the open helix
DNA Replication Base Pairing T A C G G C Left Strand Original DNA Right Strand Original DNA
DNA Replication Base Pairing T T A C G G C Left Strand Original DNA Right Strand Original DNA New Right DNA Strand
DNA Replication Base Pairing T T A C C G G C Left Strand Original DNA Right Strand Original DNA New Right DNA Strand
DNA Replication Base Pairing T T A C C G G C C Left Strand Original DNA Right Strand Original DNA New Right DNA Strand
DNA Replication Base Pairing T T A A C C C C G G Left Strand Original DNA Right Strand Original DNA New Right DNA Strand New Left DNA Strand
DNA Replication Base Pairing T T A C C G G C C A G Left Strand Original DNA Right Strand Original DNA New Right DNA Strand New Left DNA Strand
DNA Replication Base Pairing T T A C C G G G C C A G Left Strand Original DNA Right Strand Original DNA New Right DNA Strand New Left DNA Strand
3. DNA Zips Up • An enzyme zips the new molecules back up.
T T T A A A C C C G G G C C C G G G DNA Replication • Voila! • Two identical strands of DNA!
DNA Replication Review Step 3 Step 2 Step 1
T T A A C C G G C C G G Now that DNA has replicated, we are ready to begin Mitosis (nucleus of the cell divides)
Parent Cell DNA condenses into chromosomes Chromosomes align on the equator Chromosomes separate DNA uncoils
Cytokinesis • Cleavage (indention in cell membrane) or cell plate formation occurs. • Cell divides. Plant Cell Animal Cell
It’s all about the chromosomes! • There are 46 in human body cells • The number of chromosomes remain constant during Mitosis
Which Cells Go Through Mitosis? Cells which help the body in: Growth Repair Work
Mitosis Review 1. Is the beginning parent cell diploid or haploid (2n or n)? 2. Are the daughter cells diploid or haploid (2n or n)?
More Mitosis Review 3. How many daughter cells are produced? 4. Are the resulting daughter cells different from the parent cell?
More Mitosis Review 5. Are the resulting daughter cells different from each other? 6. How many chromosomes are in a human parent cell? 7. How many chromosomes are in a human daughter cell?
More Mitosis Review 8.What types of cells are produced by mitosis? 9. Why (when) does a cell go through mitosis?
Meiosis Sexual Reproduction (two parents)
Why Meiosis? • Meiosis -
Crossing Over • What is happening? • How does this affect the individual (offspring)?
Meiosis Review • Is the beginning parent cell diploid or haploid (2n or n)? 2. Are the resulting daughter cells diploid or haploid (2n or n)?
More Meiosis Review 3. How many daughter cells are produced? Are the resulting daughter cells different from the parent cell?
More Meiosis Review 5. Are the resulting daughter cells different from each other? 6. How many chromosomes are in a human parent cell? 7. How many chromosomes are in a human daughter cell?
More Meiosis Review 8. What types of cells are produced by meiosis?
Mom Dad New Individual Fertilization 23 23 46