Control of blood glucose is very important. Sufficient glucose must be delivered to cells for respiration, but too much glucose can eventually result in coma or even death. The concentration of glucose is affected by factors such as eating and exercise, and must be brought back to the normal level of about 4mmol/L to 5.5mmol/L.... Continue Reading →
The nervous system communicates information by sending nerve impulses. In the last article we saw how impulses are generated at receptors in response to a stimulus. Now the impulses must be transmitted by neurones. In this article we will look at some of the different types of neurones found in the nervous system, and see... Continue Reading →
Today we are beginning a new series about nervous communication (the type that happens in animals, not making a speech in front of the class). We will cover the nervous system in a lot of detail over the next few articles, but today we are going to start by looking at receptors. What are receptors?... Continue Reading →
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 low concentration to an area... Continue Reading →
Osmosis is all about the movement of water. Specifically, it is the diffusion of free water molecules from an area of high water potential to an area of low 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 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 →
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 →
Lipids are a particular interest of mine as my PhD was based on fat metabolism. They have important functions in the body, and can be both friend and foe. Fatty Acids Fatty acids all have the same basic structure, but have a variable R group which is a long hydrocarbon chain. If there are no... Continue Reading →
