Endosymbiosis and evolution of Organelles Essay

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

Currently, there are two major competing theories for the endosymbiotic origin of eukaryotic cells. The first theory claims that the eukaryotic cell is a combination of an archaeon with a

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 purpose of this study is to identify four unknown organisms. The unknown organisms have been assigned randomly to six-research groups by Professor Hoffman. Each research group was provided two eukaryotes and two prokaryotes. The unknown organisms will fall into the following classifications: bacteria, algae, fungi, or protozoans. All living organisms are organized into one of three domains of life, Bacteria, Archaea, and Eukarya.

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.

In my research paper, I will attempt to determine how the perception of light in phytochromes plays a role in the development of plants. Specifically, I will look at how phytochromes play a role in the growth and development of Arabidopsis thaliana. The paper will also look at how light perception plays a role in phototropism and the immune systems of a plant. Finally, my paper will explore how changing light conditions impact perception in phytochromes.

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).

The common photobiont genus is Trebouxia (Parmotrema, n.d.), which is a commonly referred to as green algae (Trebouxia, n.d.). This means that the photobiont of Parmotrema dilatatum is a uni-celled species of green algae. The mycobiont, or the fungal partner within the lichen, of P. dilatatum is unknown. The photobiont of lichen is essential because without it the mycobiont would not be able to use any of the photosynthetic produced food. But, the mycobiont of P. dilatatum is just as important because it provides protection and an anchor to the photobiont. This is a symbiotic relationship, or where both the photobiont and mycobiont benefit from living and interacting with each

Chlorophyll-a is a specific form of Chlorophyll, used in oxygenic photosynthesis. Measurement and determination of this parameter are the basic analysis to evaluate the characteristics of algae blooms in many research works in the world. Unfortunately, Chlorophyll-a represents just the whole quantity of photosynthesis pigment released from all algae and micro-plants present in water, hence it cannot help to distinguish cyanobacteria existence among all living micro plants and algae in the waterbody. To be able to define and confirm the existence of Cyanobacteria species in the composition of aquatic microalgae, another pigment form, Phycocyanin, is used. Phycocyanin is the pigment, which differs cyanobacteria species from another planktonic species, and could give us a real picture of quantity of cyanobacterial genera in the water. Phycocyanin is actually a pigment-protein complex from the light-harvesting phycobiliprotein family, along with allophycocyanin and phycoerythrin. It is considered as an accessory pigment to

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.

Their primary function is to convert energy from food in to something cells can use. This process is called oxidative phosphorylation. Within this process, adenosine triphosphate is created using oxygen and simple sugars. Mitochondria also participate in the regulation of the self-destruction of cells, or apophysis, the production of cholesterol, and of heme. However, even mitochondria cannot function without help. Mitochondrial DNA contains the 37 genes essential for the function of mitochondria. Thirteen of those genes provide instructions for making enzymes in oxidative phosphorylation and the remainders contribute to the creation of RNAs (U.S. National Library of Medicine. 2016,

Mitochondria is considered to have developed from proteobacteria and and chloroplast from cyanobacteria. She also discovered the theory of symbiogenesis, which explores the interconnections of prokaryotic and eukaryotic cells. It also explores the concern that mitochondria and plastids have their own DNA. In contrast to Neo-Darwinism, Margulis holds the belief that life did not take over the globe by combat, but by

Eukaryotes come in two grades of organization: single-celled (protists) and multicellular (plants, animals, and fungi). The world today is full of complex multicellular plants and animals: how, why, and when did they evolve from protists?