El tamaño de la célula | La estructura de una célula | Biología | Khan Academy en Español

Summary

This video explores the fascinating topic of cell size, delving into both the smallest and largest cells found in nature. It highlights how bacterial cells are as tiny as 1 micrometer, while human egg cells can reach 100 micrometers. The video explains the key factor limiting cell size: the surface area-to-volume ratio, which impacts the cell's ability to exchange nutrients and waste. As a cell grows, its volume increases faster than its surface area, making efficient nutrient exchange difficult. The video also discusses how cell shape can influence size limitations, offering insights into why cells, especially human ones, don’t exceed a certain size.

Takeaways

• 😀 The size of cells varies greatly, ranging from tiny bacterial cells to large human egg cells.
• 😀 The smallest known cells are around 100 nanometers in size, which is a fraction of a micrometer.
• 😀 Bacterial cells are approximately 1 micrometer in width and 5 micrometers in length.
• 😀 Human red blood cells have a diameter of about 7 micrometers, while white blood cells are of a similar size.
• 😀 Human egg cells are among the largest cells in the body, with a diameter of around 100 micrometers.
• 😀 A key factor limiting cell size is the relationship between surface area and volume.
• 😀 As a cell grows, its volume increases faster than its surface area, making it harder to exchange nutrients and waste efficiently.
• 😀 The surface-area-to-volume ratio for a sphere is proportional to the radius divided by 3.
• 😀 The larger a cell grows, the more difficult it becomes for its surface to manage the entry and exit of substances.
• 😀 For very large cells (e.g., 3000 micrometers in radius), the surface area would be insufficient to handle the volume, leading to inefficiency in nutrient exchange.

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