Endosymbiosis

Hi!!

                            Its already 4 weeks.Wow, time flies so quickly!In our lecture, we had already covered the endosymbiosis theory which was new to me. I find that it 's hard to  believe since nobody have seen it happened before and ever since middle school, I 've thought that mitochondria and chloroplast was naturally there like any other organelles.However, now that I've learned endosymbiosis theory, I honestly kinda feels confuse but as a student I will try to understand the concept of it and memorize it accordingly.It is kinda funny because I imaged it like the game 'PacMan' since from my understanding endosymbiosis is about a large ancestral eukaryotic cell engulfed two smaller prokaryotes and became  the eukaryote as it is now. The two smaller prokaryote; one of them were a heterotroph while the other were autotroph.Even though , after being engulfed it did not die and self-replicate in the larger ancestrial  eukaryotic cell itself which then became an eukaryote.

Endosymbiosis theory suggests 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.

                         Based on what I have learned,  some scientists have approved of the theory due to some evidences that they have found from their observation. This is because mitochondria and chloroplasts are similar in size and morphology to bacterial prokaryotic cells like reproduction system which is by binary fission, just as bacteria do, their chemically distinct membrane systems and ect. We did discussed all the similarities that linked mitochondria,chloroplast ,eukaryotes and prokaryotes  together in the lecture as shown below and we did an SCL activity which is a Venn Diagram on the similarities and differences of mitochondria and chloroplast.Its easier to understand since it is classified systematically.

 

There are a lot of new things that I have learned this week.  As for next week, Dr.Parameswari is going to teach us cell cycle and totipotency.I hope I will understand the topic better.