https://www.khanacademy.org/science/revision-term-2-tg-biology-class-8/x04828215b460a495:week-2/x04828215b460a495:cell-the-basic-unit-of-life/v/scale-of-cells-dubv 2025-05-29T08:44:44.739717086Z Scale of cells Even though molecules, proteins, viruses, and cells are all tiny, there are significant size differences between them. The diameter of a water molecule is roughly 0.28 nanometers. The diameter of the protein hemoglobin is roughly 5 nanometers. The diameter of the HIV virus is roughly 120 nanometers. A red blood cell is 6-8 micrometers. Let's learn more about the scale of cells in this video. Dubverse video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Scale of cells Even though molecules, proteins, viruses, and cells are all tiny, there are significant size differences between them. The diameter of a water molecule is roughly 0.28 nanometers. The diameter of the protein hemoglobin is roughly 5 nanometers. The diameter of the HIV virus is roughly 120 nanometers. A red blood cell is 6-8 micrometers. Let's learn more about the scale of cells in this video. https://cdn.kastatic.org/ka-youtube-converted/e762tUv7sT8.mp4/e762tUv7sT8.mp4 439 Introduction to Cell and its size https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/cell-size/e/cell-size-exercise 2026-04-08T08:09:55.69362548Z Cell size Test your knowledge of cell size! Haider Ali Bhatti exercise