Video Transcript
Which of the following best
explains the relationship between light intensity and translocation? (A) A higher light intensity means
more sugars are made by photosynthesis and thus a higher rate of translocation. (B) A higher light intensity means
more sugars are made by respiration and thus a higher rate of translocation. (C) A higher light intensity means
more sugars are made by photosynthesis and thus a lower rate of translocation. Or (D) a higher light intensity
means more sugars are made by respiration and thus a lower rate of
translocation.
This question is asking us about
the relationship between light intensity and translocation. Let’s remove the answer choices for
now and get started by reviewing what the word “translocation” means.
Translocation is the movement of a
sugar called sucrose in a plant. But where does the sucrose come
from in the first place? Photosynthesis is the process by
which organisms like plants use light energy to turn carbon dioxide and water into
oxygen and glucose, which is also a kind of sugar. Glucose can react with oxygen in
cellular respiration to provide energy for all the plant’s living cells. But first it needs to reach those
cells.
Remember, translocation moves
sucrose around the plant, not glucose. This is because while glucose
reacts with oxygen in cellular respiration, sucrose does not. So it’s easier to translocate
around the plant. As photosynthesis requires light
energy to function, the higher the light intensity, the faster the rate of
photosynthesis and therefore the faster the rate of glucose production. The more glucose that is made in
photosynthesis, the more sucrose could be transported around the plant via
translocation. As a result, as light intensity
increases, the rate of translocation also tends to increase.
So now we know the correct answer
to this question. The best explanation of the
relationship between light intensity and translocation is (A). A higher light intensity means more
sugars are made by photosynthesis and thus a higher rate of translocation.
