Although known for its bright pink-red colour, watermelon snow, scientifically known as Chlamydomonas nivalis, is actually a species of green algae. While most forms of green algae thrive in fresh water habitats, C. nivalis can be found within the snowfields of mountains and on top of glaciers; this is surprising as other species of green algae would not be able to survive in such a harsh, cold environment.
The Chlamydomonas nivalis are eukaryotic cells which contain several different organelles. These organelles help the cell to survive, reproduce, and carry out daily activities, such as photosynthesis. Surrounding the cell is a protective layer made from cellulose, called the cell wall. Inside the cell, the organelles are engulfed in a fluid within the cytoplasm; this substance is known as cytosol. The cytosol surrounds four other organelles: the nucleus, vacuoles, mitochondria, and golgi. The nucleus acts as the control centre of the cell, and also contains the cell's DNA. The vaculoes, which are found to be much larger in most plant cells, are used in the process of photosynthesis. The mitochondria are organelles that can be found in all other plant cells, and are incharge of converting food, taken in by the cell, into usable energy. The golgi are thin membranes that create the cell's products and also move and secrete its waste. Outside the cytosol, the chloroplast surrounds two other organelles: the starch granules and the pyrenoid. The starch granules are the organelles responsible for producing starches, which are then stored in the pyrenoid. The chloroplast in Chlamydomonas nivalis produce a red substance that protects them from the abundance of UV rays in their environment, and thereby allows them to photosynthesize without being damaged. Lastly, outside the cell there are two flagella which are used for locomotion.
Test Your Knowledge!
To complete the following activities, print these pages and follow each set of instructions.
Using the clues below, fill in the blanks and look for the words in the wordsearch.
- The Chlamydomonas nivalis belongs to the domain Eukarya, therefore it is classified as a __________.
- The organism is controlled by an organelle called the ________, which contains the “blueprints” (chromosomes-functions) of the cell.
- The cell contains two whip-like tails that help it move around. They are called __________.
- Chlamydomonas nivalis are commonly found in high-altitude glaciers, and snowfields. When the snow that contains these algal cells is compressed, the colour of the snow changes into a pinkish colour. This effect is called ______________.
- The cell is classified into the Phylum Green ______.
- Classified in the kingdom Protista, this cell is a _______.
- Chlamydomonas cells contain a pigment-secreting ________, which is used to produce energy through photosynthesis.
- This algal cell is __________, therefore it can not be seen with the naked eye.
- This organism is categorized in the genus ______________.
- The species of the cell is scientifically known as ________.
Label the Diagram
From the information on the structure of the Chlamydomonas nivalis cell above, name each of the organelles based on the given descriptions, and match each description to the corresponding organelle (using the numbers) on the diagram.
(a) These organelles can be found in all plant cells as they are used in photosynthesis, but are much smaller in the Chlamydomonas Nivalis cell.
(b) The circular organelle that is found within the cytoplasm of the cell, and is responsible for holding starches needed later by the cell.
(c) This organelle is responsible for creating, secreting, and moving the cell’s products. (hint: it is made up of many thin membranes).
(d) This organelle contains the DNA of the cell, and also controls the activities and functions that go on within the cell.
(e) This outer layer of the shell protects the organelles, maintains the cell’s shape, and is made of cellulose.
(f) These organelles are responsible for converting food into usable energy for the cell.
(g) The organelles that surround 9.) and are used in the process of making starches.
(h) The fluid that surrounds most of the cell’s organelles within the cytoplasm.
(i) This organelle secretes a red substance in order to protect the cell from the harmful UV rays of the sun, and is usually green when found in other species of chlamydomonas cells.
(j) These are the two whip-like tails that help move the cell around.
Word Search Answer Key
- watermelon snow
Label the Diagram Answer Key
(a) 2 (contractile) vacuoles
(b) 10 starch granule
(c) 7 golgi
(d) 4 nucleus
(e) 5 cell wall
(f) 3 mitochondria
(g) 9 pyrenoid
(h) 8 cytosol
(i) 6 chloroplast
(j) 1 flagellum
Information on the Internet
- Chalmydomonas An article about the genus Chlamydomonas; briefly talks about the structure of the nivalis species.
- Watermelon Snow: A strange phenomenon created by the algal cells of the Chlorophyta An article about the existence of watermelon snow.
- Chlamydomonas Gives the complete classification of the Chlamydomonas nivalis using the Linnean system