Another amazing enzyme video

Here's another amazing enzyme video produced by Sarah and Alyssa from the SL Biology class.

How do enzymes work?

Some students from the Gr 11 SL Biology class made an animated video of how enzymes work to catalyse chemical reactions. They also show in the video how inhibitors can stop enzymes from working. Have a look below it's been posted on Youtube..

2009 Gr 11 Biology Field Expedition

In the week before the holidays the Gr 11 Biology students traveled to Tioman Island to study various ecosystems in order to compliment the current topic, Ecology and Evolution.

On the five day course students studied in depth the ecology of coral reefs, primary and secondary rainforests and both coastal and estuarine mangroves. Each student completed two major pieces of work while away; one involved collating data through various techniques to compare primary and secondary rainforests, the other was a personal project. The personal project requires them to develop a research question regarding a particular ecological aspect of Tioman Island. They then spend an afternoon in the field gather data relating to their question. This year we had personal projects relating to the claw waving behviour of fiddler crabs, the angle of bending of coconut trees, the attraction of insects to different coloured paper flowers and the distribution of different species of sea cucumbers. Our students worke hard and the time spent was very worthwhile.

Why are plants green?

Chlorophyll is the pigment responsible for making plants green and it is found in the chloroplasts of plant cells. It is responsible for capturing light energy from the Sun and using it to drive photosynthesis in the chloroplast.

The Science Department recently purchased a spectrophotometer which allows students to expose samples of solutions to many different wavelengths of light and then measure how much of the light a solution absorbs.

In order to utilise the spectrophotometer, the Gr 12 Higher Level Biology class recently asked the question: "Does the chlorophyll from different plants show similar absorbance spectra?"

To answer this question they extracted the chlorophyll from diffent green leaves and exposed the chlorophyll solution to different wavelengths of light using the spectrophotometer.

The results of their experiment are shown in the graph below. Each line represents the absorbance spectrum of one type of chlorophyll. As it shows, the chlorophyll samples all showed peaks of absorbance at wavelengths in the blue and red areas of the visible spectrum. The difference in height of the peaks is due to the different concentrations of chlorophyll in each sample. The low level of absorbance in the green area explains why plants are green - they absorb red and blue light but reflect green light!