BIOL 150 – Homework 4: Cell Respiration and movement of carbon
BIOL 150 – Homework 4: Cell Respiration and movement of carbon Problem 1 The graph shows the pH difference across the inner mitochondrial membrane (i.e. pH in matrix – pH in intermembrane space) in an active cell. At the time indicated by the vertical arrow, a metabolic poison is added that binds to ATP synthase and prevents hydrogen ions from passing through it. a. On the graph draw what you would expect to see for the rest of the graphed line. b. Explain why you would expect to see the results that you graphed. Hint: Remember pH is a measure of hydrogen ion concentration in a solution. The chart below shows the H+ concentration that is associated with a few pH values: pH 4 7 8 H+ concentration 1 X 10-4 moles H+/L H2O 1 X 10-7 moles H+/L H2O 1 X 10-8 moles H+/L H2O Problem 2 You are a carbon atom and you are taken in by an oak tree, converted to starch which is stored in the seeds of the plant, and then eaten by a squirrel. In the squirrel, you are stored in fat; the squirrel burns up all of its fat during winter hibernation, which leaves you where? In 1) words and 2) drawing(s) describe and explain what happens to the carbon atom on this journey . Both your written explanation and sketch(es) must address the following: • • What chemical/biological processes does the carbon move through as it is traveling through the tree and the squirrel. Be specific. Where you (the carbon atom) start out and end up Hint: In class on Thursday, we learned that plants get there carbon from carbon dioxide in the atmosphere, so you (as a carbon atom) will start out as part of a molecule of carbon dioxide in the atmosphere and then you will enter the tree. To trace the rest of your path you will need to understand how carbon enters and moves through photosynthesis, the catabolic and anabolic reactions associated with cell respiration, and how a carbon atom moves through cell respiration. You (as a carbon atom) should end up back in the atmosphere as part of a molecule of carbon dioxide.