Chlamydomonas is a unicellular organism, the hallmark of which is the presence of two apical flagella. It is a genus of green algae that lives in stagnant water and on moist soil, as well as in fresh or sea water. The structure of chlamydomonas has a number of features. Among them are ion channels that are activated by direct exposure to light, as well as a red photosensitive eye and a complex regulatory system.
Chlamydomonas: general information
By type of nutrition, most species are obligate phototrophs. But some are optional heterotrophs that can grow in the dark using acetate as a carbon source. According to their morphology, these are motile unicellular algae, usually oval. The cell wall consists of a glycoprotein. Chlamydomonas reproduce both sexually and asexually.
In total there are about 150 species. Chlamydomonas actively propagates in a humid environment, as well as in waters rich in ammonium compounds. Structural features of chlamydomonas include the presence of pigments. The turbid green color of water in stagnant bodies of water is due to the presence of thousands of these flagellated microorganisms. The bright red pigment in one species contributes to coloring the habitat in scarlet or pink. Some species are found in the most unexpected locations, for example, in salty sea water.
Chlamydomonas structure
In the cervical spine are two flagella originating from the basal grain located in the cytoplasm. At their base are contractile vacuoles. Chlamydomonas cell structure suggests the presence of a cup-shaped chloroplast, where the cell nucleus is located. Here, starch is formed from the products of photosynthesis, as well as a protein surrounded by starch grains. A spotted eye is present in the front of the chloroplast. It consists of two or three more or less parallel rows of linearly organized drops of fat.
Structure Features
In its vegetative stage, the body has a very simple structure. Its size ranges from 0.02 mm. Each cell has a spherical, ellipsoidal, cylindrical or pear-shaped shape. They tend to taper at the front end. The structure of chlamydomonas includes a thin cell outer wall, two flagella, as well as two contractile vacuoles, responsible for respiration and excretion. The orange-red pigment or eye (stigma) is located in the thickness of the cell wall and performs the function of primitive vision, as it is very sensitive to light. Some species may have two or three eye spots. In the wide part of the body in the cytoplasm there is a large cup-shaped chloroplast, inside of which there is a nucleus.
How does the cell structure change during asexual reproduction?
The structure of chlamydomonas undergoes some changes during cell division. Asexual reproduction occurs in the following way: when favorable conditions are created, zoospores are formed, the cell becomes immobile, flagella hide or are discarded, contractile vacuoles also disappear, the protoplast is divided longitudinally into two parts, each of which, in turn, is divided into 2 parts. Thus, any cell produces from 2 to 16 similar formations. Gradually, in young individuals, all structures characteristic of green algae appear : flagella, vacuoles, and so on. Each of them develops into a new plant. This separation process is repeated every 24 hours. Thus, by the end of the week, about two million formed individuals are formed from one mother plant.
Features of sexual reproduction
During sexual reproduction, the cellular protoplast is divided into 16, 32, or even 64 flagellar gametes, which can be uncovered or enclosed in a cell wall. Sex cells merge into pairs, forming a zygote. As a result, it rounds off, withdraws flagella, forms a thick wall around the cytoplasm and plunges to the bottom of the reservoir for further development. In this form, it is resistant to temperature extremes and can survive even if the pond dries. Zoospores and gametes are morphologically similar. They differ only in size and behavior. This difference arises due to a greater number of divisions of the mother cell during the formation of gametes. Thus, small individuals lose their ability to exist independently.