Video Transcript
Which of the following is not an
example of a plastid found in a plant cell? (A) Leucoplast, (B) chloroplast,
(C) chromoplast, or (D) cytoplast.
The question asks us about
plastids, which are organelles found in plant cells and some types of algae
cells. In plants, plastids possess a
double membrane, meaning they are surrounded by two phospholipid bilayers and are
primarily involved in the synthesis and storage of food. There are many kinds of
plastids. But to answer our question
correctly, we can stick to discussing the three major categories found in plant
cells.
The plastid type you’re probably
already familiar with are chloroplasts. These contain chlorophyll, a green
pigment that absorbs red and blue wavelengths of light more efficiently than other
wavelengths. The photons from red and blue light
are then used in photosynthesis to make food for the plant.
The second major type of plastids
are chromoplasts. They make and store red, yellow,
and orange pigments, which give plant foods like bell peppers and tomatoes their
bright colors. These pigments serve to attract
pollinators to flowers and other animals to eat the plant’s fruits, thereby
dispersing the seeds found inside. They also protect the plant from
environmental stressors, such as UV light and pollution.
The third major type of plant
plastids are the leucoplasts. The prefix leuco- means white,
which you may remember from learning about leukocytes. Leucoplasts get their name because
they do not contain pigments and therefore are colorless. Their primary function is to store
starch and fat for the plant.
We now have the information we need
to answer our question correctly. We need to choose the answer that
is not considered a plastid. So we can exclude answers involving
the chloroplasts, chromoplasts, and leucoplasts we’ve just discussed. Therefore, the correct answer is
(D). A cytoplast is not an example of a
plastid found in a plant cell.
