Lecture Notes: Mitosis and Meiosis

Introduction

• The lecture focuses on comparing mitosis and meiosis.
• Exploration of their occurrence in life stages.

Key Concepts

• Egg and Sperm Formation: Occurs via meiosis.
• Fertilization: Combination of egg and sperm to form a zygote.
• Development stages involve extensive mitosis.

The Cell Cycle

• Two Main Stages:
  • Interphase (90% of the cell's life)
    • Sub-phases: G1, S, G2
  • Mitosis (10% of the cycle)
    • Sub-phases: Prophase, Metaphase, Anaphase, Telophase
  • Cytokinesis follows mitosis.

Mitosis Details

• Purpose: Produce daughter cells genetically identical to the parent.
• Chromosome Consistency: Daughter cells have the same number of chromosomes as the parent cell.
  • e.g., Parent cell with 46 chromosomes -> Daughter cells with 46 chromosomes.

Stages of Mitosis

• Prophase: Chromosomes condense; spindle apparatus forms.
• Metaphase: Chromosomes align at the cell equator.
• Anaphase: Sister chromatids separate and move to opposite poles.
• Telophase: Chromosomes decondense; nuclear envelope reforms.
• Cytokinesis: Division of the cytoplasm into two cells.

Visual Aids and Animations

• Interactive Animations: Provided for understanding mitosis stages (e.g., Cells Alive).
• Kinetochore: Handles at centromeres aiding in chromosome movement.

Hands-On Activity

• Demonstration using hands to visualize mitosis stages.

Identification in Real Cells

• Animal Cells: Differences noted in stages when compared to plant cells.
• Plant Cells: Presence of cell wall affects cytokinesis (cell plate formation).

Telomeres and Cell Division

• Function of Telomeres:
  • Protect chromosomes from degradation.
  • Regulate the number of cell divisions.
• Aging and Telomere Length
  • Correlation between telomere length and organismal age.
  • Genetic conditions like Progeria demonstrate effects of shortened telomeres.

Case Study: Progeria

• Impact: Accelerated aging due to shortened telomeres.
• Symptoms: Early onset of age-related diseases, shorter lifespan.

Conclusion

• The lecture provided insights into mitosis, its stages, and relevance in life cycles.
• Discussion on telomeres and their role in aging and genetic disorders.

Note: Additional resources such as animations and videos were suggested for further study.