FRQ Biology Unit 2 Progress Check
Exam Questions & Answers 2025/2026
(a) Identify the most likely mode of transport across the membrane for substance L. Explain how
information provided helps determine the most likely mode of transport. - ANSWERSThe
response indicates that substance L most likely crosses the membrane by active transport.
The response indicates that the cells maintain an intracellular concentration of 120 mM, which
is always greater than the concentration of substance L in the culture medium.
(b) On the axes provided, construct an appropriately labeled line graph with correct scale and
units to illustrate the data in Table 1. - ANSWERS/
(c) Determine the external concentration of substance L that will result in one-half of the
maximal entry rate. - ANSWERSThe response indicates that the external concentration of
substance L that will result in one-half of the maximal entry rate is between 31 mM and 34 mM
(d) Predict the likely effect on the ability of substance L to enter the cells if substance L is
attached to a large protein instead of free in the culture. - ANSWERSThe response indicates that
substance L will be unable to enter the cells if it is attached to a large protein OR the response
indicates that substance L will be unable to enter the cells if it is attached to a large protein
unless there is a specific cell membrane receptor for the protein.
(a) Describe the biological need for cells to be surrounded by a membrane that is selectively
permeable for different materials. - ANSWERSThe response indicates that a cell membrane
separates the internal environment of the cell from the external environment OR that a cell
membrane that is selectively permeable can help to regulate what molecules move between
the differing environments inside and outside of a cell.
Exam Questions & Answers 2025/2026
(a) Identify the most likely mode of transport across the membrane for substance L. Explain how
information provided helps determine the most likely mode of transport. - ANSWERSThe
response indicates that substance L most likely crosses the membrane by active transport.
The response indicates that the cells maintain an intracellular concentration of 120 mM, which
is always greater than the concentration of substance L in the culture medium.
(b) On the axes provided, construct an appropriately labeled line graph with correct scale and
units to illustrate the data in Table 1. - ANSWERS/
(c) Determine the external concentration of substance L that will result in one-half of the
maximal entry rate. - ANSWERSThe response indicates that the external concentration of
substance L that will result in one-half of the maximal entry rate is between 31 mM and 34 mM
(d) Predict the likely effect on the ability of substance L to enter the cells if substance L is
attached to a large protein instead of free in the culture. - ANSWERSThe response indicates that
substance L will be unable to enter the cells if it is attached to a large protein OR the response
indicates that substance L will be unable to enter the cells if it is attached to a large protein
unless there is a specific cell membrane receptor for the protein.
(a) Describe the biological need for cells to be surrounded by a membrane that is selectively
permeable for different materials. - ANSWERSThe response indicates that a cell membrane
separates the internal environment of the cell from the external environment OR that a cell
membrane that is selectively permeable can help to regulate what molecules move between
the differing environments inside and outside of a cell.
