lecture recording on 21 February 2025 at 13.57.06 PM

Overview of Mitosis

• Mitosis: Process of genetic material division, also known as cell division. Focuses on the division of genetic material, excluding cytoplasmic components.

Stages of Mitosis

• Mitosis consists of four stages:

  • Prophase

  • Metaphase

  • Anaphase

  • Telophase

• Interphase: Non-mitotic stage where the cell performs regular functions, consisting of Gap 1, Synthesis, and Gap 2.

Prophase

• Chromatin Condensation: Chromatin folds to form visible chromosomes.

• Nuclear Envelope Breakdown: The membrane separating the nucleus from cytoplasm disintegrates, allowing genetic material to be accessed.

• Spindle Formation:

  • Spindle apparatus, made of microtubules, begins to form and attaches to chromosomes.

  • Centrioles: Organizing structures located at opposite poles of the cell in animal cells; absent in plant cells (plant cells use microtubule organizing centers).

Metaphase

• Chromosomes align at the cell's equatorial plane due to equal tension exerted by spindle fibers.

Anaphase

• Sister chromatids are pulled apart by the spindle fibers, now considered as individual chromosomes, moving towards opposite poles of the cell.

Telophase

• Decompaction of Chromosomes: Chromosomes begin to unwind back into chromatin.

• Nuclear Envelope Reforms: Newly formed nuclei emerge around the chromatin.

• Spindle Disassembly: The spindle apparatus is dismantled.

• Cytokinesis: Physical division of the cytoplasm occurs, pinching off to form two separate daughter cells.

Differences in Plant Cells

• In plant cells, cytokinesis involves the formation of a new cell wall between the two daughter cells, in addition to the plasma membranes.