WEEK 5- ENDOSYMBIOSIS THEORY / CELL CYCLE AND TOTIPOTENCY

For week 5, I learnt about endosymbiosis theory. Endosymbiosis theory is an evolutionary theory that explains the origin of eukaryotic cells from prokaryotes. What I really understand for this topic is for mitochondria and chloroplast in eukaryote in which originally arise form prokaryotes. Endosymbiosis theory suggest that :eukaryotes arose from a symbiotic relationship between various prokaryotes. • heterotrophic (aerobic) bacteria became mitochondria. • cyanobacteria (photosynthetic) became chloroplasts. • host cell was a large eukaryotic cell.

The theory come out base on the comparison of timeline and the characteristic. For this topic, I did a SCL group activity and compare the prokaryote to the mitochondria and chloroplast. From the comparison, we also conclude the endosymbiosis theory that eukaryote is arise from various of prokaryote. The SCL activity is mental challenge but beneficial to improve our understanding about the endosymbiosis theory.

The picture above is cell cycle. There is interphase phase that consist of G1(Gap 1) phase, S (synthesis) phase and G2(gap 2) phase. The interphase is a phase in which the cell is preparing all the requirement before triggering the M (mitotic) phase. Our body system is really complex. Even, the smallest unit in human body (cell) do a very complex mechanism. So, what about the other? Maybe more complex and complicated. How amazing our body are. In this cell division topic, I exposed to the mechanism of cell division (mitosis), the regulation of cell cycle and others.

The image is the phases in mitotic phase. Other than the cell cycle, I also learned about totipotency. Totipotency is a new topic for me. It is very interesting topic. It about growing a plant using it cell. It is a laboratory technique in growing a plant in unique style and using suitable medium. Totipotency is the ability of a individual plant cell/tissue/organ to regenerate into a whole plant under right condition (Gottlieb Haberlandt , 1902). Below is the example of totipotency.

Totipotency require suitable condition to occur like the temperature, nutrient, moisture, pH and other. It not easy to do cell culture. That what I think.