The photosynthetic single cellular alga Chlamydomonas reinhardtii has been used as a model organism to examine in detail the physiological, biochemical and molecular processes of photosynthesis, flagella synthesis and movement, mineral stress, interactions between nucleus, chloroplasts and mitochondria and other processes. In this review we summarize part of the current knowledge on adaptive responses in C. reinhardtii when it is exposed to oxidative stress and to changes in light intensity, concentration of minerals, herbicides and metals. The individual responses are linked in order to understand the response of the cell, which is continuously subjected to fluctuations, as a whole