Video Transcript
In a plant cell, what is the
movement of cytoplasm that allows the movement of metabolites, nutrients, and
organelles called? (A) Chlorophyll flow, (B)
homeostasis, (C) cytoplasmic streaming, or (D) sap flow.
There are movements that occur on a
cellular level in plant cells, such as the movement of cytoplasm described in the
question. This type of movement is well
observable under the microscope within the cells of some aquatic plants, including
Elodea canadensis or Hydrilla verticillata. Let’s go through the different
answer options to figure out which one is correct.
If we have a look at a typical
photosynthetic plant cell, we can observe that it contains chloroplasts. Chlorophyll is a pigment found
within chloroplasts, which allows the plant to perform photosynthesis. Chlorophyll, however, does not
float around in the chloroplast and has nothing to do with the movement of
cytoplasm. So we can exclude answer option
(A).
Homeostasis is the maintenance and
regulation of a constant, normal internal environment that allows the biological
processes to function properly within an organism. Many processes play a role in
homeostasis, including nerve signaling and hormonal regulation. However, the movement of cytoplasm
is not called homeostasis. Therefore, we can exclude (B).
Cytoplasmic streaming is defined as
the constant, unidirectional flow of the cytoplasm within a cell. This does looks like it could be
the correct answer, but let’s look at the last one to be sure.
Sap generally describes the liquid
within the vascular system of a plant. This includes water and nutrients
absorbed from the soil, as well as sugars produced during photosynthesis, which are
carried to where they are needed around the rest of the plant. Even though sap flow includes the
movement of some of the substances listed in the question, the liquid is called sap
and not cytoplasm. And no organelles are moved
around. So we can eliminate (D).
The correct answer to the question
is indeed given by answer choice (C). The movement of cytoplasm that
allows the movement of metabolites, nutrients, and organelles is called cytoplasmic
streaming.
