Experiment: Different Stages of Meiosis I

Aim:

To observe and identify the different stages of meiosis I in onion root tip cells using microscopy.

Materials:

1. Microscope with high-power and oil immersion objectives

2. Prepared slides of onion root tip cells undergoing meiosis

3. Coverslips

4. Kimwipes or lens paper

5. Pen and notebook for recording observations

Experimental Procedure:

1. Place a prepared slide of onion root tip cells undergoing meiosis on the microscope stage.

2. Start with low-power magnification and focus on the root tip area.

3. Switch to high-power magnification to observe individual cells in detail.

4. Identify and record the different stages of meiosis I, including prophase I, metaphase I, anaphase I, and telophase I.

5. Pay attention to key characteristics of each stage, such as synapsis, crossing over, chromosome alignment, and homologous chromosome separation.

6. Take note of the distribution and arrangement of chromosomes and spindle fibers during meiosis I.

7. Draw and label diagrams of representative cells at each meiosis I stage to document your observations.

Observations:

– Prophase I: Chromosomes condense and pair up, undergoing synapsis and crossing over.

– Metaphase I: Paired homologous chromosomes align along the cell equator.

– Anaphase I: Homologous chromosomes separate and move toward opposite poles.

– Telophase I: Chromosomes reach the poles, and the nuclear envelope reforms.

Results:

– Meiosis I stages demonstrate reduction division and genetic recombination.

– Synapsis and crossing over promote genetic diversity.

– Reductional division ensures each daughter cell receives one homologous chromosome from each pair.

Conclusion:

Observing meiosis I stages highlights the process of genetic recombination and reduction division, essential for generating genetic diversity in sexually reproducing organisms.