Translocation is the movement of dissolved substances (also called solutes or assimilates) through the phloem vessels. If you haven't already, make sure to read about the structure of the phloem vessels here first so you've got a good grounding to take this topic further. Source to Sink Solutes move from a source to a sink.... Continue Reading →
In the last post we looked at the structure of the xylem vessels, so now we're going to take a look at their function. Water transport in plants happens up the xylem vessels in a transpiration stream from roots to leaves due to the properties of water and transpiration at the leaves. Let's break the... Continue Reading →
Today we're starting on transport in plants. Plants don't have hearts or blood, but they still need to transport substances around because they are too big to rely on diffusion alone. The tissues involved in transport are the xylem vessels and the phloem vessels. In this article we will focus on the xylem and phloem... Continue Reading →
So far in the exchange and transport series we have mainly been looking at exchange and transport of gases. However, organisms also need to absorb nutrients such as glucose and amino acids so they can carry out processes like respiration and protein synthesis. In this article we will cover how large food molecules are broken... Continue Reading →
Getting blood around the body requires a network of blood vessels. These come in different shapes and sizes depending on their location and function. In this article we will look at the structure of arteries, veins, capillaries. Arteries Arteries carry oxygenated blood away from the heart to the tissues of the body (except the pulmonary... Continue Reading →
The cardiac cycle is the sequence of contraction and relaxation that the heart goes through continuously to keep blood pumping around the body. It's fairly complicated, but broken down into steps it makes sense if you think about the direction blood travels through the heart. Two important words you need to know before we start... Continue Reading →
So far in this series we've looked at how substances are exchanged across membranes, particularly oxygen and carbon dioxide in gas exchange systems. Today, we're going to start looking at how substances get transported around organisms, starting off by looking at the structure of the human heart. The Human Heart The heart is the key... Continue Reading →
Sometimes it's easy to forget that plants exchange gases too because you can't see evidence of ventilation. As well as needing oxygen for respiration, plants also need carbon dioxide for photosynthesis. In addition, oxygen is a waste product of photosynthesis and carbon dioxide is a waste product of respiration. Dicotyledonous Plants First of all, what... Continue Reading →
Fish and insects don't have lungs like humans and other mammals do. Instead, they have clever alternative gas exchange systems in order to deliver oxygen to their cells. Let's look at each organism individually. Gas Exchange in Fish I'm sure it's fairly obvious that fish don't breath air because they live underwater. Instead, they must... Continue Reading →
We've now looked at three ways in which substances can be transported across cell membranes: diffusion, osmosis, and active transport. Today's topic is example of where diffusion takes place in the human body, all with the purpose of taking in oxygen for respiration and removing carbon dioxide. There's quite a lot of information today so... Continue Reading →
