Video Transcript
Assuming the plant is alive and
healthy, which of the following conclusions about the experimental setup shown below
is correct? (A) The plant will be respiring but
not photosynthesizing. (B) The plant will be
photosynthesizing but not respiring. (C) The plant will not be respiring
or photosynthesizing. Or (D) the plant will be
photosynthesizing and respiring.
Let’s remove the multiple-choice
options for now and remind ourselves about respiration and photosynthesis. You may recall that plant cells
carry out two very important chemical reactions. The first is respiration, and the
second is photosynthesis. Aerobic respiration is the process
whereby glucose is broken down in the presence of oxygen to produce carbon dioxide
and water and to release energy in the form of ATP. This is how plants get all the
energy they need to survive. Photosynthesis is the process
whereby plants convert carbon dioxide and water into glucose and oxygen using light
energy.
Because photosynthesis relies on
light energy, it can only happen when the Sun is out or in the presence of some
other light source. Respiration, on the other hand,
happens constantly with or without a light source. Now, let’s consider the
experimental setup shown in the diagram.
We’re told that the potted plant is
alive and healthy; therefore, we know that it will be respiring. We can also see that the plant is
receiving light energy from this lamp, which means it will also be
photosynthesizing. We have therefore concluded that
with this experimental setup, the correct answer is (D); the plant will be
photosynthesizing and respiring.
