Extension

Shape of Mitochondria Activity

Now that you have constructed a model of how mitochondria work, let’s
look closer at the structure of the mitochondria.
As we have seen, mitochondria must be very efficient in order to make all
the ATP the millions of cells in the body need. In this activity you will
investigate how the inner shape of the mitochondria allows it to work more
efficiently.
Work together with your group but each member should make
their own model.
Collect the needed materials from your teacher: scissors,
construction paper, pencil, metric ruler
PROCEDURE:
1) Use the scissors to cut a sheet of construction paper in half to form
two rectangular pieces. Label one piece A. Label the other piece B.
2) Use a metric ruler to measure the length and width of piece A. Find
the area of A by multiplying it’s length by it’s width. Record this number
as the total surface area on A.
3) Fold piece A as shown with 10 sections and 9 folds.
4) Lay the folded piece A on top of piece B. On piece B, mark the
position of piece A.
5) Cut off and discard the part of piece B that was not covered by
piece A.
6) Measure the length and width of the remaining piece B. Find the
area of the remaining piece B using the method you used for piece A.
Record this number. This is the space taken up by A after it was folded.
242
RESULTS AND CONCLUSIONS
1. a. Which piece is greater, the surface area of A (the folded piece) or the
surface area of B that was covered by A?
b. What is the difference in the areas of
A and B?
c. What causes this difference?
2. How could the difference between the area covered (B) and the total
surface area (A) be made even greater?
3. Think about how the folding of the paper might be similar to the inner
membrane of a mitochondrion. Talk to your group and see if you can come
up with some possible shapes. Hint: the outer membrane is relatively
smooth and shaped either like a ball or like a fat hotdog.
The chemicals in the mitochondrion only work if they are attached to
membranes.
Suppose that pieces A and B represent inner membranes of two
mitochondria. Which mitochondrion (A or B) could provide more surface
area for chemicals to be attached and therefore do a more efficient job?