Biology Test Questions
1. What is the relationship between rate of ion exchange and surface-to-volume ratio?
- As the surface-to-volume (SA:V) decreases the rate of ion exchange will also decrease.
2. Why is it important for a cell to have a large surface-to-volume ratio?
- If the SA:V is too small then then rate of ion exchange will decrease, if this rate of ion exchange is too low then the cell will no longer be viable.
3. Which is more efficient at exchanging materials, a small or a large cell? EXPLAIN.
- A small cell would be more efficient at exchange of materials from its surrounding environment as once material enters the cell it would be more evenly distributed internally. In bigger cells the concentration of materials near the periphery
would be greater than near the centre thus the cell would have to even out the concentration gradient to allow more material to enter.
4. Some cells in the body have adapted to the task of absorption and excretion of large amounts of materials. In what ways have these cells adapted to this task?
- Cells have adapted to the task of absorption and secretion by adapting one of the following:
- becoming wide and thin as in the case of nerve cells
- becoming convoluted to increase the surface area in contact with the environment, e.g.microvillus
5. How does cell growth affect the cell's surface-to-volume ratio?
- On the assumption of the cell being spheroidal in shape, as the cell grows the SA:V decreases, until a point is reached where any further increase in size would make the cell nonviable.
6. In order for a cell to continue being efficient at exchanging materials, what must it do to maintain its surface-to-volume ratio as it grows larger?
- For the cell to continue growing and maintain a viable SA:V it would have to adapt its shape so as to be wide and thin
this is because according to Fick's law the rate of diffusion is influenced by the surface area since the insect has to maintain optimal diffusion levels there is a limitation in the extent to which each insect type can expand its tracheal diameter
- As the surface-to-volume (SA:V) decreases the rate of ion exchange will also decrease.
2. Why is it important for a cell to have a large surface-to-volume ratio?
- If the SA:V is too small then then rate of ion exchange will decrease, if this rate of ion exchange is too low then the cell will no longer be viable.
3. Which is more efficient at exchanging materials, a small or a large cell? EXPLAIN.
- A small cell would be more efficient at exchange of materials from its surrounding environment as once material enters the cell it would be more evenly distributed internally. In bigger cells the concentration of materials near the periphery
would be greater than near the centre thus the cell would have to even out the concentration gradient to allow more material to enter.
4. Some cells in the body have adapted to the task of absorption and excretion of large amounts of materials. In what ways have these cells adapted to this task?
- Cells have adapted to the task of absorption and secretion by adapting one of the following:
- becoming wide and thin as in the case of nerve cells
- becoming convoluted to increase the surface area in contact with the environment, e.g.microvillus
5. How does cell growth affect the cell's surface-to-volume ratio?
- On the assumption of the cell being spheroidal in shape, as the cell grows the SA:V decreases, until a point is reached where any further increase in size would make the cell nonviable.
6. In order for a cell to continue being efficient at exchanging materials, what must it do to maintain its surface-to-volume ratio as it grows larger?
- For the cell to continue growing and maintain a viable SA:V it would have to adapt its shape so as to be wide and thin
this is because according to Fick's law the rate of diffusion is influenced by the surface area since the insect has to maintain optimal diffusion levels there is a limitation in the extent to which each insect type can expand its tracheal diameter