Topic 3 The Chemistry of Life! So what is so special about water?

Well that was Topic 2 (so you know what must be coming next – a topic test)! We are now about to embark on the next topic,  The Chemistry of life. Here are the syllabus outlines for Topic 3, and also Topics 7 and 8  (as they are extensions of Topic 3).Topic-378-syllabus-outline If you like Biochemistry then you are in for a wonderful 36 hours of pure chemical pleasure; if not then be prepared to dig in for the long haul. There is a lot of really important Biochemistry here that you need to know. Topics 7+8 are part of the Additional Higher Level, so for a while we will be saying goodbye to our SL colleagues. More about this later.

The first couple of hours we will spend looking at the basic chemical elements of life, and water. Now this does not sound too exciting, but actually water is very special in the way it behaves. It has a higher boiling point than you would expect (H2S is a gas at room temperature), water molecules stick to each other (Cohesion) and stick to other substances (Adhesion). It can also dissolve ionic substances, has a high specific heat capacity, and is opaque; all features which make it very useful for living organisms!

We will perform a web search to answer the following questions

  • What are the most frequently occurring chemical elements in living things?
  • Why are calcium, sulfur, phosphorus, sodium and iron needed by plants, animals or prokaryotes?
  • What does a water molecule look like?
  • What are the thermal, cohesive and solvent properties of water?
  • How do these properties relate to water’s use in living organisms as a coolant, medium for metabolic reactions and transport medium?

We will answer the questions using the attached worksheet produced by a previous colleague of mine, Mr Eamonn Hobbins. ! Topic 3 Water-Web-quest

Now you have had the opportunity to find out the information for yourself, here are the answers. Make sure that you find the time to check your answers against the ‘official’ answers! Water-Web-quest-MScheme

You may find this slideshare presentation useful here to complete the web quest

Next we will look at the following major groups of molecules, Carbohydrates, Proteins and Fats. We will make use of another of Stephen Taylor`s slideshares

Lance Armstrong, a lead in to the Cell Cycle (I know its lame), Mitosis, and what happens when Mitosis goes wrong!

Now we are about to start the section of this topic that all students seem to dread, the Cell cycle and Mitosis. In reality, for mitosis to occur billions of times in each of our bodies it must be a straightforward process; if it were not it would go wrong a lot more often than it actually does.

For information on what we mean by the cell cycle check out

For an explanation of what occurs during the various stages of mitosis we can look at and Cytokinesis

Why dont eukaryotes just divide by binary fission like prokaryotes do? Check out this explanation

Finally why did I start with Lance Armstrong – Mitosis and Cancer!

We will be using another presentation from Mr Taylor in Indonesia  and we will also look at performing an online simulationto identify the various stages of Mitosis in onion root tip cells.