A Human Karyotype Preparation Animation

Summary

The video script describes the process of creating a karyotype, starting with blood collection and cell analysis. Blood cells are grown in a medium that stimulates mitosis, and colchicine is added to stop division at metaphase. After centrifuging and treating with a hypotonic solution, cells are prepared and observed under a microscope. Chromosomes are photographed, enlarged, and cut out. They are then arranged by homologous pairs, creating a karyotype diagram, which is used to study chromosomes, such as in identifying a normal male's karyotype.

Takeaways

• 🩸 Blood is collected from the person to be analyzed.
• 🧫 The blood is added to a growth medium containing a chemical that stimulates mitosis.
• ⏳ Cells are allowed to grow for two to three days at body temperature.
• 🔬 Colchicine is added to arrest cell division at metaphase.
• 🧪 Arrested cells are transferred to a centrifuge tube for concentration.
• 🔄 Centrifugation causes the cells to concentrate at the bottom of the tube.
• 💧 A hypotonic salt solution is added, causing the cells to swell and spread apart.
• 🔍 The cells are prepared, fixed, and placed on a microscope slide for observation.
• 📸 A cell's chromosomes are photographed, enlarged, and individual chromosomes are cut out.
• 📊 Chromosome images are aligned by homologous pairs to produce a karyotype of a normal male.

Q & A

What is the first step in preparing a karyotype from a blood sample?

The first step is collecting blood from the person being analyzed and adding it to a growth medium that contains a chemical to stimulate mitosis.

Why is a chemical that stimulates mitosis added to the blood sample?

The chemical stimulates mitosis so that the cells will begin dividing, making it easier to capture them at the metaphase stage, where chromosomes are most visible.

For how long are the cells allowed to grow in the medium, and at what temperature?

The cells are allowed to grow for two or three days at body temperature.

What role does colchicine play in this process?

Colchicine is added to arrest cell division at metaphase, the stage where chromosomes are most condensed and easily visible.

What is the purpose of centrifugation in this procedure?

Centrifugation concentrates the cells at the bottom of the tube, making it easier to separate and work with them.

How does the addition of a hypotonic salt solution affect the cells?

The hypotonic salt solution causes the cells to swell and move apart, making their chromosomes more distinguishable.

What is done to the cells after they are prepared and fixed?

The prepared and fixed cells are placed on a microscope slide for observation.

How are the chromosomes analyzed under the microscope?

A photograph of the cell’s chromosomes is taken under the microscope, and the part of the photo showing the chromosomes is enlarged. Images of individual chromosomes are then cut out.

How are the chromosomes arranged to create a karyotype?

The images of the chromosomes are arranged so that all pairs of homologous chromosomes are aligned horizontally by their centromeres, resulting in a karyotype diagram.

What is the final result of this process in the provided script?

The final result is a karyotype diagram of the arrested metaphase chromosomes, indicating the karyotype of a normal male.