I recently had a student who needed to make up a lab he missed. I found some useful sites for him to do a combination of an online lab and home experiment on alcoholic fermentation and cellular respiration.
1. Online lab exercise about cellular respiration. The quiz at the end is also good practice for interpreting graphs.
http://www.phschool.com/science/biology ... intro.html
I had him turn in the quiz and a sort of methods section explaining the procedures used in the simulation and what he learned from the experiment. This was mostly to make sure that he had done the exercise and had gotten something out of it. If you did it, you might do something like that for a portfolio, I suppose.
We actually use similar methods and equipment in our normal lab and one of the questions we ask that you might also use is:
a) Give two reasons why we know that germinating pea seeds aren't performing photosynthesis. (Hints: What does the KOH do? Where are pea seeds normally germinating?) - The KOH absorbs carbon dioxide that would be necessary for photosynthesis. Also, pea seeds normally germinate underground where there is no light for photosynthesis; instead, they rely on the food stores the parent plant provided them.
2. The home wet lab was about how temperature affects yeast and alcoholic fermentation.
http://www.lesaffreyeastcorp.com/SoY/experiment_4.html
I had him add a third temperature...so he used ice water, warm water, and hot water. I also suggested that 20 oz bottles would probably be more readily available than 1 L bottles. I cautioned him to put the smaller-sized bottles away from anyone just in case the pressure became too great and blew the balloon off. His write up didn't mention any problems, but it is better to err on the side of safety.
I also had my student write a hypothesis about how temperature would affect the fermentation process and then to explain in his conclusions how enzymes would be affected by the three temperatures. (There wouldn't be enough energy available in the ice water for the reactions to get over their activation energy humps. The enzymes were closer to their optimal temperature in the warm water, so fermentation could proceed quickly. And at high temperatures, there might be rapid fermentation at first as the solution heats up, but when the solution got hot enough, the heat would denature the enzymes, so they couldn't work anymore, therefore leading to a decreased fermentation rate.)
-knobren