Cell Division and Reproduction
Asexual Reproduction
Only 1 parent required for asexual reproduction.
Fast and simple process.
Results in identical offspring without genetic variation.
Examples include binary fission in bacteria.
Sexual Reproduction
Involves 2 parents contributing to offspring.
Offspring genetically different from parents.
Slower and more expensive compared to asexual reproduction.
Leads to genetic variation, aiding evolution in changing environments.
Modes of Reproduction
Asexual reproduction involves a single parent producing genetically identical offspring through binary fission.
Example: Amoeba divides by binary fission to form daughter cells.
Sexual reproduction requires two parents contributing to genetically diverse offspring.
Genetic variation in sexual reproduction allows adaptation to environmental changes.
Eukaryotic Cell Division
Mitosis produces identical daughter cells for asexual reproduction, growth, and repair.
Meiosis generates different daughter cells for sexual reproduction and gamete formation.
Meiosis results in four unique daughter cells compared to two identical cells in mitosis.
Cell Cycle and Mitosis
Eukaryotic Cell Division
Mitosis results in daughter cells identical to the parent cell.
Occurs in asexual reproduction, growth, development, and repair.
Meiosis produces daughter cells different from parents for sexual reproduction.
Involves the formation of gametes like sperm and egg.
Eukaryotic Chromosomes
Chromosomes are tightly coiled DNA structures.
Human cells (except gametes) typically have 46 chromosomes.
Genes are specific DNA sequences on chromosomes.
Chromatin, a looser DNA form, condenses into chromosomes before cell division.
The Cell Cycle
Ordered sequence of events from cell formation to division.
Consists of interphase (cell growth and DNA replication) and mitotic phase (DNA and cytoplasmic division).
Interphase includes G1 (cell growth), S (DNA duplication), and G2 (preparation for division).
Stages of Mitosis
Prophase: Chromosomes coil tightly, spindles form.
Prometaphase: Nuclear envelope breaks, microtubules attach to chromatids.
Metaphase: Chromosomes align at the cell's equator.
Anaphase: Sister chromatids separate and move to opposite ends.
Telophase: Chromosomes decondense, nuclear envelope reforms.
Cytokinesis: Cytoplasm divides, forming two daughter cells.
Mitosis and Cell Division
Mitotic Spindle
Microtubules that separate chromosomes during mitosis.
Aids in pulling DNA to opposite ends of the cell.
Essential for proper chromosome distribution.
Ensures accurate division of genetic material.
Mitosis Summary
Results in two daughter cells identical to the parent cell.
Utilized in asexual reproduction, growth, and repair.
Mathematically, chromosome count doubles during S phase and halves after cytokinesis.
Ensures genetic stability and continuity in cell populations.
Comparing Binary Fission and Mitosis
Both processes involve chromosome duplication and cell division.
Mechanics and timing differ between bacterial binary fission and eukaryotic mitosis.
DNA replication and separation occur simultaneously in binary fission, unlike in mitosis.
Mitotic spindle formation is unique to eukaryotic cell division.
Cancer and Cell Cycle
Cell cycle checkpoints regulate cell division.
Disruption of checkpoints, like the G1/S checkpoint, can lead to cancer.
Tumors result from uncontrolled cell growth.
Benign tumors stay localized, while malignant tumors can metastasize.
Eukaryotic Chromosomes and Cell Cycle
Chromatin and Chromosomes
Chromatin organizes DNA into chromosomes before cell division.
Gene: a sequence of nucleotides on a chromosome.
Sister chromatids are duplicated chromosomes held by a centromere.
The Cell Cycle Phases
Interphase: cell growth and DNA replication stages.
Mitotic Phase: includes mitosis and cytokinesis for cell division.
Mitosis stages: Prophase, Prometaphase, Metaphase, Anaphase, Telophase.
Updated 259d ago
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