Does Sugar Affect the Growth of Yeast?

We wanted to see whether the amount of sugar added affected the growth of the yeast.  To do this we made up 3 different mixtures

Bowl 1:   Yeast and water only - some small amounts of the yeast tried to foam up but not much                          happened

Bowl 2:   Yeast, water and 1 teaspoon sugar - the mixture foamed up and rose quite quickly and held                  its shape

Bowl 3:   Yeast, water and 5 teaspoons sugar - did foam up and rise but at a much slower rate, but after a while it began to slowly callapse.

So yes, sugar does affect the growth of yeast.

Because yeast is only one cell it can't make its own food, so we need to give it food (sugar).  The yeast eats the sugar and makes carbon dioxide.

We then added flour to each of the mixtures and made them into a dough and baked each one to see whether there would be any difference in taste.  Below are some comments.

Bowl 1 (No sugar)                       Most didn't like this one
The yeast taste was stronger because there was no sugar to balance it
There was nothing to cover the taste of the yeast
Was a bit dry

Bowl 2 (1 teaspoon sugar)          Majority liked this one
Tasted more like bread
Was softer

Bowl 3 (5 teaspoons sugar)         2 or 3 really liked this one
Very sweet
Cake like flavour
Had a stronger flavour/taste