Question

question 4 of 10
a biologist wants to test the rate of absorption into several different types of
cells, including red blood cells, muscle cells, and epithelial cells. she will use
radioactive labels to tag various molecules, which she can monitor and
record as they are taken up by each cell type. which molecule should the
biologist tag with the radioactive label in order to collect the data she is
looking for?

a. atp
b. water
c. carbon dioxide
d. glucose

Explanation:

• ATP is produced within cells, not typically absorbed from outside.
• Water is absorbed, but its absorption mechanism (osmosis) is more about concentration gradients and not as diverse in terms of cell - type - specific uptake mechanisms compared to glucose.
• Carbon dioxide is a waste product in most cells (except in some autotrophic cells during photosynthesis - but the cell types mentioned are not autotrophic in this context) and is usually diffused out rather than absorbed in the way the question implies.
• Glucose is a key molecule that is actively or passively transported into cells (different cell types may have different transport mechanisms). For example, red blood cells use facilitated diffusion for glucose uptake, while muscle cells can take up glucose via insulin - regulated transporters. Tagging glucose would allow the biologist to study the rate of absorption across different cell types.

Answer:

D. Glucose