Mitosis How do your cells divide? Ch. 6 and Ch. 7
Chromosome Talk
A few words before we start….. Haploid: (n) 1 set of unpaired chromosomes Diploid: (2n) 2 haploid sets of chromosomes (1 pair)
Why Do Cells Divide? Surface area Damaged cells Sex cells
Cell Reproduction is either sexual or asexual
Asexual Reproduction (one parent) Binary Fission- Budding Vegetative Propagation Regeneration
Advantages of Asexual Reproduction Speed Desirable Characteristics Replacement
DNA Structure Ch. 9 Made up of nucleotides There are 3 parts to each nucleotide –Deoxyribose sugar –Phosphate group –One of 4 Nitrogen bases
A G G T C C Nucleotide Phosphate group Deoxyribose Sugar Nitrogen Base
Nitrogen Bases There are four possible nitrogen bases: Adenine (A)Thymine (T) Cytosine (C)Guanine (G) A G T C
Nitrogen Base Pairing These bases always pair together in DNA: Adenine (A)Thymine (T) Cytosine (C)Guanine (G) A G T C
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.
A G G T C C DNA Replication DNA Unzips
A G G T C C
A G G T C C
A G G T C C
A G G T C C
A G G T C C Left Strand of Original DNA Right Strand of Original DNA
2. Base Pairing Complementary bases match with each DNA strand in the open helix
A G G T C C Left Strand Original DNA Right Strand Original DNA DNA Replication Base Pairing
A G G TT C C Left Strand Original DNA Right Strand Original DNA New Right DNA Strand DNA Replication Base Pairing
A G G T C T C C Left Strand Original DNA Right Strand Original DNA New Right DNA Strand DNA Replication Base Pairing
Left Strand Original DNA Right Strand Original DNA New Right DNA Strand A G G T C C T C C DNA Replication Base Pairing
Left Strand Original DNA Right Strand Original DNA New Right DNA Strand A G G T C C T C C A New Left DNA Strand DNA Replication Base Pairing
Left Strand Original DNA Right Strand Original DNA New Right DNA Strand New Left DNA Strand A G G T C C T C C A G DNA Replication Base Pairing
Left Strand Original DNA Right Strand Original DNA New Right DNA Strand New Left DNA Strand A G G T C C T C C A G G DNA Replication Base Pairing
3. DNA Zips Up An enzyme zips the new molecules back up.
DNA Replication Voila! Two identical strands of DNA! T C C A G G T C C A G G T C C A G G
DNA Replication Review Step 1 Step 2 Step 3
Remember - All this takes place in INTERPHASE G2G2
Now that DNA has replicated, we are ready to begin Mitosis (nucleus of the cell divides) T C C A G G T C C A G G
Parent Cell DNA condenses into chromosomes Chromosomes align on the equator Chromosomes separate DNA uncoils Prophase Metaphase Anaphase Telophase MITOSIS
Cytokinesis Cleavage (indention in cell membrane) or cell plate formation occurs. Cell divides. Animal Cell Plant Cell
The Cell Cycle
Mitosis Animation
Overview of the Cell Cycle PMAT
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? Growth Repair Work Cells which help the body in: The cells are called autosomes
What happens if cell division gets out of control ? CANCER The body doesn’t respond normally to the body’s control mechanisms p. 127,
Bone Cancer X-ray Ovarian Cancer Cell Dividing
Skin Cancer
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?