Life107, semester 2 practical 1 in a test-tube

107 Practical 1 is just around the corner, so here is your trusty summary of what to expect :)

Practical 1 is actually split into two halves - you will be setting up two different experiments and then you will be collecting and analyzing the results in your next practical session.

Experiment 1 will involve our friends the fruit flies (actually, I'm no great fan of these little bugs!). You will be setting up some crosses to investigate Mendel's 1st law of inheritance.

Experiment 2 is an ecotoxicology experiment - you will be testing the sensitivity of two strains of the yeast Saccharomyces cerevisiae to H2O2. One of the strains you are testing will have several mutations in its genome and your goal is to test whether these mutations have given the mutant yeast any survival advantage over the wild-type yeast when exposed to the toxin H2O2.

Here are some of the things this day is going to teach you about:

• how to set up crosses with fruit flies - Drosophila melanogaster 
• how to interpret data from crosses that illustrate Mendel's laws 
• how to design an experiment to measure the relationship between the dose of a toxin and its effect
• sterile technique
• calculating cell density
• making serial dilutions
• analyzing dose-response data using regression techniques

You may not understand some of the above points - but by the end of the two linked practicals you will know about them all !!

 The day will be split into 7 activities (these are split into morning and afternoon activities but there may be some overlap....) :

IN THE MORNING

ACTIVITY 1 : Read about Mendel's laws and Drosophila

ACTIVITY 2 : Design and set up your fly experiment - you will be investigating the inheritance of eye colour

ACTIVITY 3 : Read about experimental design of dose-response testing, and work through an example showing how calculate the dose that will kill 50% of the yeast - this is the LD50

ACTIVITY 4 : Practise using a haemocytometer to count cells

ACTIVITY 5 : Design your yeast experiment - you will be investigating the sensitivity of wild type and mutant strains to the toxin H2O2.

IN THE AFTERNOON

ACTIVITY 6 : Perform your spectacularly planned yeast experiment 

ACTIVITY 7 : If you have time, answer some questions related to inheritance (if you don't have time, you will have to finish these off in the next session)

Posts related to this practical are on the way :)