Biology Question

Question

A cell containing a 3% sucrose solution is placed into a beaker containing a 7% sucrose solution. Assume the cell’s membrane is permeable to water, but not permeable to the sucrose. Where will the water diffuse? Explain.

True or false: Each turn of the Calvin cycle produces one molecule of glucose. If false, please make it a true statement.

Answer 1

7% solution is a higher concentration of sucrose which means more sugar per amount of water. If you put the 3% and 7% on either side of a membrane and the membrane only allows water through, water will move from the 3% side to 7% side to try and dilute down the more concentrated side. Basically the water will move from where there is MORE water per sugar (3%) to where there is LESS water per sugar (7%).

False. Six turns of the Calvin cycle produces one molecule of glucose.

You make glucose from a precursor called G3P. For each rotation of the calvin cycle you only produce 1 spare carbon. Because G3P contains 3 carbons, you would need to do the cycle 3 times just to make 1 spare G3P that can go on to make glucose. However, you need a total of 2 G3P molecules total to make a molecule of glucose (a 6 carbon molecule), therefore you would need to go around the calvin cycle a total of 6 times (input 6 CO2s) in order to make 1 molecule of glucose.