Essay - Origin of Eukaryotes Theory of Endosymbiosis the Evolution of Eukaryotes...

Origin of Eukaryotes

Theory ***** Endosymbiosis

The evolution of eukaryotes has no fossil record. However, from the study of modern organisms, biologists deduced their theory that eukaryotes evolved ***** prokaryotes through the endosymbiosis process. The state of one species living inside a*****ther species, known as the host, is called endosymbiosis.

Eukaryotes evolved from ***** Archaea domain of prokaryotes, whereby prokaryotic cell have engulfed aerobic bacteria instead of engulfing other prokaryotes. Membrane infolding is the first ***** that occurs in the development of eukaryotic cell. Around the nucleus, nuclear envelope is formed due to ***** inward folding ***** the plasma membrane. Later, attached to ***** ***** envelope, endoplasmic reticulum is produced. The development process of mitochondria and chloroplasts completes the formation ***** eukaryotic cell.

***** of the researched evidences of ***** on the evolution of eukaryotes from ***** are as follows. (Origin ***** Eukaryotes. (http://www.sidwell.edu/us/science/vlb5/Labs/Classification_Lab/Bacteria/symbiosis.html)

Both use RNA and DNA are ***** genetic material

***** ***** the same 20 amino acids

Both ***** ribosomes and DNA and RNA - - in other words the same cell mach*****ery for protein synthesis.

Both have a lipid bilayer cell membrane.

Both use L amino acids and D sugars

The origins of mitochondria and chloroplasts are the main focus of eukaryotes' *****. The process of endosymbiosis involves three types ***** prokaryotic cells: cells that are absorptive and ingestive of inorganic matters, highly oxidized ***** that ***** good for energy process, ***** photosyn*****thic cells ***** develop organic compounds using light energy.

***** of Mitochondria

During ***** infolding, highly oxidized prokaryotic cells are ingested in eukaryotic cells. These cells ***** too small and *****digestible. Instead of being digested, they continue to live inside the host that becomes an ideal environment for them beca***** of the organic molecules ***** inorganic ***** ***** host provides them. The energy released by the endosymbiotic cell (the ingested small ***** *****), on the other hand, provides benefit to the host making it more productive and successful. After some time, the endosymbitic cells lose *****ir cellular au*****nomy and later become a mitochondrion.

***** of Chloroplasts

The origin of ***** is almost the ***** as that of *****. Some eukaryotic cells ingest small prokaryotic photosynthetic cells. These photosynthetic cells provide the ***** with organic molecules while the host ***** them with ***** compounds. Eventually, the ***** cells lose their cellular autonomy and then ***** become chloroplasts.

However, contrast to mitochondria, not all eukaryotic cells ingest chloroplasts. This is the reason why all eukaryotes contain mitochondrion but not ***** ***** *****.

Bibliography

Origin of Eukaryotes.

2003. George Washington University. 23 April 2003. http://www.gwu.edu/~darwin/BiSc151/*****/Eukaryotes.html

Endosymbios***** in Evolution.

*****. Sidwell Friends School. 23 ***** 2003. http://www.sidwell.edu/us/science/vlb5/Labs/Classification_Lab/Bacteria/symbiosis.html

***** Orig***** of Eukaryote Chloroplast.