The Theory Of The Serial Endosymbiotic Theory

When life arose on Earth about 4 billion years ago, the first types of cells to evolve were prokaryotic cells. For approximately 2 billion years, prokaryotic-type cells were the only form of life on Earth. The oldest known sedimentary rocks found in Greenland are about 3.8 billion years old. The oldest known fossils are prokaryotic cells, 3.5 billion years in age, found in Western Australia and South Africa. The nature of these fossils, and the chemical composition of the rocks in which they are found, indicates that these first cells made use of simple chemical reactions to produce energy for their metabolism and growth. Eukaryotic cells evolved into being between 1.5 and 2 billion years ago. Eukaryotic cells appear to have arisen from prokaryotic cells, specifically out of the archaea. Indeed, there are many similarities in molecular biology of contemporary archaea and eukaryotes. However, the origin of the eukaryotic organelles, specifically chloroplasts and mitochondria, is explained by evolutionary associations between primitive nucleated cells and certain respiratory and photosynthetic bacteria, which led to the development of these organelles and the associated explosion of eukaryotic diversity. Today Prokaryotes

A more recent evolutionist of the theory is Lynn Margulis, who is famous through her research career that mainly focused on this concept. It was Biologist Lynn Margulis from Boston University who in 1967 began to tell an older view. She suggested that certain prokaryotes had been overtaken by larger more active species. Instead of being digested inside the host cell some victims continued to thrive and grow. The theory of Endosymbiosis describes the origin of chloroplasts and mitochondria and their double membranes. This concept explains the idea that chloroplasts and mitochondria are the results of years of evolution started by endocytosis of bacteria and blue green algae. Based on this theory, blue green algae and bacteria are not

Endosymbiosis is the theory that eukaryotic cells were formed when a prokaryotic cell ingested some aerobic bacteria. The first step of the evolution of a eukaryotic cell is the infolding of the cellular membrane. This process takes place when the plasma membrane folds inwards and develops an envelope around a smaller prokaryotic cell. Once the smaller cell is engulfed, it becomes dependent upon its host cell. It relies on the host cell for organic molecules and inorganic compounds. However, the host cell also benefits because it has an increased output of ATP for cellular activities and becomes more productive. This ATP comes from the mitochondrion (the aerobe) that is engulfed.

Mitochondria are small organelles found in eukaryotic cells which respire aerobically. They are responsible for generating energy from food to ‘power the cell’. They contain their own DNA, reproducing by dividing in 2. As they closely resemble bacteria, it gave the idea that they were derived from bacteria (which were engulfed by ancestors of the eukaryotes we know today). This idea has since been confirmed from further investigations, and it is now widely accepted. (Alberts et al., 2010a)

7. The theory of endosymbiosis says that mitochondria and plastids used to be small prokaryotes living within larger cells. The prokaryotic ancestors of mitochondria and plastids were bacteria engulfed by a larger cell. Because they both benefited from this situation, the bacteria living inside the cell was passed down from generation to generation. The evidence is that mitochondria reproduce and move independently within the cell.

The cells of a eukaryote are different from any other cells because they do not have cell walls, and have organelles. An example of an organelle is the nucleus. Mitochondria are the energy providers for cells. A symbiotic relationship is when to organisms benefit from living together. When one organism lives inside the other, it is known as endosymbiosis. Chloroplasts trap sunlight and make photosynthesis possible. Once two organisms live together for a while, they loose their ability to live

Microscopic  organisms  known  as  cyanobacteria are  interesting  for  the  following  reasons: [SELECT  ALL  THAT  APPLY] Select  one  or  more: A.  Oxygen  produced  by  their  photosynthesis is  thought  to  be  responsible  for  the  "great oxygenation  event"  about  2.3  billion  years ago.   B.  The  methane  they  produce  is  a greenhouse  gas  that  could  have  helped warm  the  early  Earth,  helping  to  resolve  the Early-­faint-­Sun  paradox. C.  The  chloroplasts  that  carry  out photosynthesis  in  green  plants  are evolutionary  descendents  of  early cyanobacteria.   D.  They  are  known  to  be  the  earliest  forms of  life  on  Earth.

Chloroplasts are important photosynthetic organelles that present in plant cells. It is believed that chloroplasts evolve from an endosymbiotic event; engulfment of a photosynthetic cyanobacterium by a large heterotrophic host cell (1, 2). During this process proteins in the cyanobacterium has been transferred to the nucleus and also the proteins that are essential for organelle biogenesis has been transferred to the cyanobacterium making it dependent on the host. Although chloroplast proteins have estimated to consist of 3500-4000 different types of polypeptides, the protein coding capacity in chloroplast genes is approximately 200 polypeptides (3, 4). This data further suggest that most of the proteins found in chloroplast are encode by nuclear genome and transport to the chloroplast. At least, a few proteins are use secretory pathway in which first targeted to the endoplasmic reticulum and then transfer to the chloroplast through vesicles (5-7).

13. Who is largely responsible for proposing the endosymbiosis theory? 
A. Schimper, Wallin, Margulis
B. Lyon, Margulis, Schimper
C. Schimper, Wallin, Barr
D. Barr, Lyon, Margulis

Bacterial symbionts are predominant among organisms that shape the biological world (Hurst 1993, Wernegreen 2004). Some of the bacterial symbionts that have an inordinate influence on the health and evolution of their hosts are those bacteria that live within their symbiotic hosts, so-called endosymbionts. Bacterial endosymbionts are the focus of current research programs by the National Institutes of Health (Human Microbiome Project, http://www.hmpdacc.org/) and the National Science Foundation (The Symbiosis, Defense, and Self-recognition Program).

The Endosymbiotic theory is an assumption based on experience and/or limited information about the evolution of the cell. Bacteria are one of the oldest single cellular organisms. They began to make their own food using photosynthesis which then produced enough oxygen to reshape Earth 's atmosphere. This change brought upon diverse bacterial life which include clear evidence that chloroplasts and mitochondria were, at one point, crude bacterial cells. Over the years, chloroplasts and mitochondria became dependent on a host cell. After millions of years of evolution, chloroplasts and mitochondria cannot survive outside of the cell. This is the Endosymbiotic theory. Although this is labeled a theory, there is striking evidence that shows similarities in both bacteria, and mitochondria and chloroplasts. They all have their own DNA (separate from the nucleus), and they both use this DNA to produce proteins and enzymes for their functions.

Once a upon time, there was a lonely mitochondria named Sophia Mitochondria. Sophia Mitochondria had been alone for a while and she does not know where her parents are. She want to find her parents so she decided to talk someone to help her which is her childhood best friend, David Chloroplast. However, before she called him, she did her normal routine. She took nutrients from one of their cells, breaks it down and turn it into energy. This routine is also known as cellular respiration. After that, she call her David Chloroplast and thirty minutes later, David Chloroplast was in front of her house. David Chloroplast and Sophia Mitochondria came to Bacteria Garden which Sophia Mitochondria’s parents favorite place to go every weekend. When they

The second important endosymbiotic event occurred as a result, in the acquisition of mitochondria by the earliest eukaryotes (Avissar et al., 2016). Mitochondria are responsible for aerobic cellular respiration in eukaryotic cells, and for a long time it was believed that they were simply organelles. But much like plastids in photoreactive eukaryotes, the evidence points to mitochondria having been absorbed by early eukaryotes, forming a symbiotic relationship in which the larger cell protected the smaller and provided a ready source of nutrients, and in turn the mitochondria allowed the larger cells to process all of the new molecular oxygen as an energy source to promote glycolysis (Cooper, 2000).

The biochemical process at work is the cause of mitochondrion, a membrane-bound organelle found in the cytoplasm of

It is widely accepted that mitochondria and chloroplasts descended from free-living bacterial ancestors (Dyall et al. 2004). Following their acquisition by eukaryotic cells during endosymbiotic evolution, most of the genes in these organelles were either lost or transferred to the nucleus. Today, it is demonstrated that from all mitochondrial proteins (over 1500) most of them (93-99%) are encoded in the nucleus, synthesized in the cytoplasm and then imported into the organelles (Woodson and Chory 2008). For instance, human mtDNA only contains 37 genes and codes for 13 encoding polypeptides, 22 tRNAa, and 2 rRNAs (Ryan and Hoogenraad 2007). The relationship between organelles and the nucleus is continually evolving to suit an organism’s needs.