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The Eukaryotic Cell Cycle, Mitosis, and Meiosis - Coggle Diagram
The Eukaryotic Cell Cycle, Mitosis, and Meiosis
Eukaryotic Cell Cycle
Phases
G1: Cell growth; decision to divide
S: DNA replication; sister chromatids form
G2: Preparation for mitosis; protein synthesis
M Phase
Mitosis (Mitotic Cell Division)
Produces two genetically identical diploid daughter cells
Stages
1.Prophase: Chromosomes condense; nuclear membrane breaks down
2.Prometaphase: Spindle fibers attach to kinetochores.
3.Metaphase: Chromosomes align at the metaphase plate
5.Telophase: Nuclear membranes reform; chromosomes decondense
4.Anaphase: Sister chromatids separate and move to opposite poles.
6.Cytokinesis: Division of cytoplasm into two cells
Meiosis and Sexual Reproduction
Produces four haploid gametes from a diploid cell
Key differences from mitosis
Meiosis I: Homologous chromosomes separate, crossing over occurs
Meiosis II: Sister chromatids separate (similar to mitosis)
Promotes genetic diversity through
Crossing Over: Exchange of genetic material between homologs
Independent Assortment: Random distribution of chromosomes.
G0: Resting phase for non-dividing cells
Checkpoints
G1 Checkpoint: Ensures favorable conditions for division
G2 Checkpoint: Checks DNA replication and damage
Metaphase Checkpoint: Verifies chromosome attachment to spindle
Chromosome Structure and Variation
Karyotype: Visual representation of chromosomes.
Chromosome abnormalities
Aneuploidy: Extra or missing chromosomes (ex: trisomy 21 - Down syndrome)
Polyploidy: More than two sets of chromosomes (common in plants)
Mutations
Deletion: Missing segment
Duplication: Repeated segment
Inversion: Reversed segment
Inversion: Reversed segment
Importance of Cell Division
Mitosis enables growth, repair, and asexual reproduction
Meiosis ensures genetic variation and is crucial for sexual reproduction
Variations in chromosome number or structure can lead to evolutionary changes or diseases