So far we have looked at the passive movement of substances across cell membranes by diffusion and osmosis. Sometimes substances need to move against a concentration gradient, which is when active transport comes into action. Active transport Active transport uses energy from ATP to transport substances from an area of lower concentration to an area... Continue Reading →
Osmosis – Exchange and Transport Ep 3
Osmosis is all about the movement of water. Specifically, it is the movement of free water molecules from an area of higher water potential to an area of lower water potential across a partially permeable membrane. As we saw in diffusion, the water molecules move both ways, but the overall net movement is down the... Continue Reading →
Diffusion – Exchange and Transport Ep 2
Diffusion is one of those topics that pops up at all levels of biology, and each time gets a little more complicated. But it is still the basic process of substances evenly distributing themselves. It is just a little more complex when it happens across a cell membrane. Simple diffusion Firstly, lets recap the basics... Continue Reading →
Cell Membrane Structure – Exchange and Transport Ep 1
Today we are starting a new series looking at how substances are exchanged across cell membranes and transported around organisms. These processes are really important for getting essential resources such as oxygen and glucose to all the cells in an organism. We will start by taking a closer look at the structure of the cell... Continue Reading →
