Centrosome and centrioles - #USMLE Cell physiology Animations

Summary

The centrosome is a crucial organelle found in the cytoplasm near the nucleus, composed of two centrioles and surrounding pericentriolar material. As a microtubule-organizing center, it plays a key role in cell division, especially in forming the mitotic spindle. Centrosomes duplicate during cell division, ensuring the proper distribution of chromosomes. The function of the meiotic spindle is vital for accurate chromosome transportation, and its inhibition, often by spindle poisons like colchicine and vinca alkaloids, halts mitosis and cell division.

Takeaways

• 😀 Centrosomes are spherical organelles found in the cytoplasm near the nucleus.
• 😀 In multinucleated cells, each nucleus has its own centrosome.
• 😀 Centrosomes consist of two centrioles arranged at right angles and a surrounding matrix of pericentriolar material.
• 😀 The centrioles are short cylindrical structures that play a key role in cell division.
• 😀 Centrosomes act as microtubule organizing centers (MTOCs) and contain gamma tubulin.
• 😀 Microtubules grow from gamma tubulin in the pericentriolar material.
• 😀 During cell division, centrosomes duplicate and move to opposite poles of the mitotic spindle.
• 😀 Centrosomes are crucial for monitoring steps in cell division.
• 😀 The proper functioning of the mitotic spindle is essential for correct chromosome segregation.
• 😀 Inhibition of the spindle, through agents like colchicine or vinca alkaloids, halts mitosis and prevents cell division.

Q & A

What is the centrosome and where is it located?

The centrosome is a spherical organelle found in the cytoplasm, near the nucleus. In multinucleated cells, a centrosome is near each nucleus.

What are the components that make up a centrosome?

A centrosome consists of two centrioles and surrounding amorphous pericentriolar material, which is referred to as the matrix.

What is the structure of centrioles in the centrosome?

Centrioles are short, cylindrical structures arranged at right angles to each other within the centrosome.

What is the function of the centrosome in cells?

Centrosomes act as microtubule-organizing centers that contain gamma tubulin, from which microtubules grow.

How does the centrosome contribute to cell division?

During cell division, centrosomes duplicate and move apart to the poles of the mitotic spindle, where they help monitor the steps in cell division.

What is the role of the centrosome in the mitotic spindle?

The centrosome is the point of origin of the mitotic spindle, which is crucial for chromosome transportation during cell division.

What is the impact of spindle poisons on cell division?

Spindle poisons inhibit the proper function of the mitotic spindle, leading to the arrest of mitosis and cessation of cell division.

Can you name a common spindle poison and how does it work?

A common spindle poison is colchicine, which inhibits microtubule polymerization, affecting the mitotic spindle.

What are some other examples of spindle poisons besides colchicine?

Other spindle poisons include vinca alkaloids and taxanes, which also disrupt microtubule functions.

Why is proper functioning of the meiotic spindle important?

Proper functioning of the meiotic spindle is essential for correct chromosome transportation during cell division, ensuring proper genetic material distribution.