AP Biology 4.6 Regulation of Cell Cycle- Exam Style questions - FRQ
Question
Lectin is a molecule commonly found in legumes. Colchicine is a molecule that inhibits the formation of spindle fibers. An experiment was performed to observe the effects of lectin and colchicine on dividing cells. A total of 300 cells were observed for each treatment.
Partial results of the experiment are shown in the following table.
(a) Describe the effect of adding lectin to the cells.
(b) Identify the independent variable and the dependent variable in
this experiment.
(c) Based on the data presented, predict the most likely effect of
adding only colchicine to the cells.
(d) Justify your prediction from part (c).
▶️Answer/Explanation
Ans:
(a) Lectin stimulates cell division, as shown by the increased number
of cells in mitosis for the treatment with only lectin added
(compared to the number of control cells in mitosis).
(b) The independent variable is the presence or absence of lectin and/or
colchicine. The dependent variable is the number of cells in mitosis
or interphase.
(c) The most likely effects of adding only colchicine to the cells would
be that the number of cells in mitosis would be less than that of the
control group and the number of cells in interphase would be more
than that of the control group.
(d) The addition of lectin alone increased the number of cells in
mitosis (compared to that of the control group). The addition of
both lectin and colchicine resulted in a number of cells in mitosis
that was much closer to that of the control group than it was to that
of the group with only lectin added. So colchicine most likely
reduces the number of cells in mitosis, and thus a group with only
colchicine added would have even fewer cells in mitosis than the
control group had.