Prokaryote Experiment
Making yogurt in Mongolia
To see some prokaryotes in action, you can make your own yogurt. Yogurt is what happens to milk when bacteria get into it and reproduce. The bacteria eat the sugar(lactose) in the milk for energy to live and reproduce themselves. They break apart the sugar molecules to get energy. They have lactic acid molecules left over, which they push out of the cell to get rid of them. These lactic acid molecules react chemically with the protein molecules in milk and make the proteins unfold and stick to each other. That makes your liquid milk turn all gloppy - that's yogurt.
How to make yogurt
Get some yogurt with live cultures in it at the store (you might have to look in the healthy food section; if it has live cultures in it, it will say so on the carton). Those live cultures are your bacteria. On the stove, slowly heat up a cup of milk until it is hot, but not boiling. It should be about 95-120 degrees Fahrenheit or 35-45 degrees Celsius. This is to kill some poisonous bacteria that might get in your yogurt.
Let the milk cool down until it is just warm, and then add 1/4 cup of the yogurt to it and mix it up. Cover the pan tightly and leave it on a sunny kitchen counter or back porch where it will stay warm (or near a woodstove). Or you can put your yogurt pan in a bowl of warm water and keep changing the water so it stays warm all day. Or put the warm bowl inside your microwave, which is insulated and will keep it pretty warm.
After about four to six hours, your milk should all have turned into yogurt. You can eat it plain, or add berries or jelly if you like it better that way.
Main prokaryote page
Eukaryotes
To find out more about cells, check out these books from Amazon.com or from your library:
