Video Transcript
What is the function of the
contractile vacuole present in both Euglena and Amoeba? (A) It collects and removes,
excretes, excess water from the organism. (B) It digests the food that has
been engulfed by the organism. (C) It controls the growth and
reproduction of the organism. (D) It responds to light allowing
the organism to find food. Or (E) it carries out
photosynthesis, so the organism can make food.
Euglena and Amoeba
are both unicellular, or single-celled, organisms. They must carry out all essential
life processes within just one cell. For example, to obtain nutrition,
Euglena cells are able to carry out photosynthesis as they have
chloroplasts. Photosynthesis uses light energy
and simple inorganic molecules to make food in the form of sugars. Amoeba cells cannot carry
out photosynthesis as they do not have chloroplasts. But they are able to engulf food
particles into their single cell.
Euglena cells can do this
too when light levels are low. Once in the cell, food particles
are contained within organelles called food vacuoles. There, these particles can be
broken down into smaller, useful molecules. As digesting food that has been
engulfed by the organism is the role of the food vacuole and not the contractile
vacuole, option (B), which suggests otherwise, is incorrect.
We also now know that Amoeba
cells cannot carry out photosynthesis. Therefore, option (E), which
suggests this is the role of the contractile vacuole in both organisms, cannot be
correct either.
As Amoeba cells do not carry
out photosynthesis, they do not respond to light to find food. Option (D), which suggests
responding to light is the function of the contractile vacuole, an organelle present
in Amoeba and Euglena cells, is therefore also incorrect.
The instructions for controlling
various life processes, such as growth and reproduction, are encoded by genetic
material. In both Amoeba and
Euglena cells, genetic material is found in an organelle called the
nucleus. As we know that it is the role of
the nucleus, not the contractile vacuole, to control growth and reproduction, option
(C), which suggests otherwise, cannot be the correct answer.
The contractile vacuole is an
organelle present both in the cells of Amoeba and Euglena. It is responsible for collecting
and then excreting excess water. Therefore, the function of the
contractile vacuole present in both Euglena and Amoeba is (A): it
collects and removes, excretes, excess water from the organism.
