Key to How to Answer Exam Questions
Section 1. Questions in this section can be answered with one or a few words.
For the following definitions, provide the correct term.
1. A genetically based change in the characteristics of a population over time.
[evolution]
2. Channel that connects the cytoplasm of two cells in plants.
[plasmodesmata]
Answer the following questions.
3. List two functions of the Golgi apparatus.
[receives products/modifies products/ships products/stores products/manufactures
macromolecules]
4. What benefit does the mitochondria gain by having infoldings in its inner membrane?
[Increased surface area for absorption]
Section 2. Short Answer.
For the following pairs of terms provide a concise definition for each that will clearly
distinguish between the two terms. Be sure to include how the two terms are related to one
another.
5. microtubules / microfilaments
[Both are internal structural support components of cells that can be assembled &
disassembled where needed in the cell. Microtubules are larger and hollow and are used to
resist compression forces. Microfilaments are smaller and solid and used to resist tension
forces.]
Answer the following questions.
6. Many proteins get made in one type of cell and then get exported for use in another type of
cell. Describe the route this type of protein would take, beginning with where it was
synthesized, what organelles it travels through and ending with how the protein is exported from
the cell.
[Proteins for secretion are made by ribosomes attached to the rough ER. They are packaged in a
transport vesicle by the ER and moved to the Golgi apparatus. The GA modifies the proteins,
wraps them in a transport vesicle and sends them to the plasma membrane. The transport vesicle
fuses with the plasma membrane, and the proteins are exported from the cell]
7. Most aspen trees reproduce asexually, which means that all of the trees within one population
are genetically identical (clones). In a population of aspen clones, will the trees evolve through
natural selection? Why or why not?
[No, the trees will not evolve through natural selection. In order for natural selection to occur,
their must be genetic variation within a population for the selection pressure to act on. The aspen
trees are clones (genetically identical), so there is no variation, so no evolution by natural
selection. (You can also answer yes if you make a clear argument for the fact that mutations do
arise within populations, that would lead to genetic variation – more on that when we cover
evolution in greater detail)]