Lecture on Cell Division and Mitosis

Introduction

• Cloning and its limitations in humans.
• Cells and their ability to clone through mitosis.

Importance of Mitosis

• Vital for growth, development, healing, and lifespan maintenance.
• Mitosis is the basis for regeneration of cells after damage or growth.
• Occurs about 10 quadrillion times in a human lifetime.

DNA and Chromosomes

• DNA is stored in the cell nucleus.
• Human somatic cells have 46 chromosomes (23 pairs) from both parents.
• Diploid cells have 46 chromosomes, haploid cells (sex cells) have 23.

Mitosis Overview

• Mitosis produces two genetically identical cells from one diploid cell.
• Involves stages: Prophase, Metaphase, Anaphase, Telophase.

Interphase

• Cells are mostly in interphase, growing and functioning.
• DNA exists as chromatin, a loosely coiled structure.
• Centrosomes duplicate.
• DNA replication occurs.

Prophase

• Chromatin condenses into chromosomes.
• Chromosomes duplicate to form chromatids (X-shape).
• Nuclear envelope disintegrates.
• Centrosomes move to opposite cell ends, forming microtubule spindles.

Metaphase

• Chromosomes align in the cell equator.
• Motor proteins facilitate chromosome alignment.
• Dynein protein studied for its role in this process.

Anaphase

• Chromatids are pulled apart to opposite ends of the cell.
• Motor proteins pull chromosomes through microtubule tension.

Telophase

• Nuclear envelopes re-form around separated chromosomes.
• Chromatin relaxes.
• Cleavage furrow forms, marking cytokinesis.
• Two daughter cells are formed, genetically identical.

Conclusion

• Mitosis is essential for cell replication, but does not explain genetic variance from parents.
• Upcoming discussion on meiosis and its role in genetic diversity.
• Engage with the content through various platforms for more learning.