Concept explainers
To review:
Biologists have long accepted the hypothesis that plastids originate by the endosymbiosis of a cyanobacterium during evolutions. It later forms primary photosynthetic eukaryotes. Until recently, there was no molecular evidence to support this assumption. If the assumption is correct, a phylogenetic tree based on molecular data should support the hypothesis that all primary photosynthetic eukaryotes have a common ancestor.
A group of scientists sequenced the amino acid in 143 proteins encoded by the nuclear genes of primary photosynthetic groups. They later compared the trees to see where the overlap occurred and generated a summary tree. Whether the figure supports or contradicts the hypothesis that a single endosymbiosis event correlated with the evolution of organisms containing plastids is to be discussed.
Introduction:
Symbiosis is also called the endosymbiotic theory. When a eukaryotic organism takes in prokaryotic cell organelles like mitochondria and plastids through endosymbiosis, they evolve and become a part of the host eukaryotic organism. This leads to the formation of plastids, which are believed to have originated from the endosymbiosis of photosynthetic cyanobacteria, later giving rise to primary photosynthetic eukaryotes.
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Biology: The Dynamic Science (MindTap Course List)
- According to the endosymbiotic theory of the origin of eukaryotic cells, how did chloroplasts originate? -by tertiary endosymbiosis -through secondary endosymbiosis -from the nuclear envelope folding outward and forming mitochondrial membranes -from infoldings of the plasma membrane, coupled with mutations of genes for oxygen-using metabolism -through primary endosymbiosisarrow_forwardDoes the following phylogenetic tree provide evidence to support or refute the endosymbiosis hypothesis? Briefly explain your choice (1-2 sentences) Bacteria a-Proteobacteria Mitochondria Archaea Eukarya Excavata Discicristata Alveolata Stramenopila Rhizaria Plantae Opisthokonta Amoebozoaarrow_forwardDescribe the features of mitochondria and chloroplasts that support the endosymbiotic theory.arrow_forward
- Algae are autotrophs and can have photosynthesis, however, evolutionary evidence suggests that plants shared a common ancestor with only green algae and are closest relatives of Charophytes. What evidences support this statement? How an algal cell is different from fungal cells, even if both are eukaryotes? Why slime mold is a protist not a fungus even if it does not have chloroplast?arrow_forwardThe prtists that causes malaria evolved from a photosynthetic ancestor and has the remnant of a chloroplast. The organelle no longer functions in photosynthesis, but it remains essential to the protist. Why might targeting this organelle yield an antimalarial drug that produces minimal side effects in humans?arrow_forward1) According to the endosymbiotic theory of the origin of chloroplasts, photosynthetic prokaryotic cells________? 2) The tremendous increase in the diversity of animals beginning about 542 million years ago is called the______? 3) Two completely unrelated species that are found in the same environment are observed to have the same adaptation. This observation describes_________?arrow_forward
- Evolution of Photosynthetic Organisms Algae are autotrophs and can have photosynthesis, however, evolutionary evidence suggests that plants shared a common ancestor with only green algae and are closest relatives of Charophytes. What evidences support this statement? How an algal cell is different from fungal cells, even if both are eukaryotes? Why slime mold is a protist not a fungus even if it does not have chloroplast? Renlyarrow_forwardEukaryotic cells can be detected at latest mid-way through the Proterozoic, and multicellular eukaryotes not long after – but there is a curious lag before the radiation of multicellular eukaryotic groups. We discussed two possible reasons for this. Explain both. Why might an early arrival of lichens on land explain aspects of both of those possibilities?arrow_forwardSome non-plant organisms like the protist that spreads malaria contain a non-photosynthetic chloroplast called an apicoplast. Crazy! What best explains how protists have evolved apicoplasts?arrow_forward
- The theory of the endosymbiotic origin of mitochondria and chloroplasts was first proposed by the biologist Lynn Which of the following statements provides support for the theory of endosymbiosis? 1. All the genes found in chloroplasts are homologous to genes found in the nucleus of eukaryotic cell. 2. Mitochondria contain their own ribosomes. 3. Proteins need a targeting sequence to be imported into a chloroplast. 4. Mitochondria can generate a proton gradient and harness it to synthesize ATP. O A. 1, 2 and 3 B. 1 and 3 C. 2 and 4 D. 4 only E. All of 1, 2, 3 and 4 are correct.arrow_forwardWhich of the following structures in chlorarachniophytes provides evidence that they evolved through the endosymbiosis of a green alga by a heterotrophic eukaryote? A. food vacuole B. nucleomorph C. mitosomes D. flagellaarrow_forwardImagine you are working in a lab and studying three species of yeast, which are eukaryotic organisms. The first species (Species A) of yeast generates ATP using aerobic cellular respiration. The second species of yeast (Species B) generates ATP using alcohol fermentation. The third species of yeast (Species C) generates ATP using lactic acid fermentation. Which of the following statements are true? All of the other answers are true. Only Species A can grow without oxygen. Species B needs to use 15-16 molecules of glucose to generate the same amount of ATP that is made by Species A using one molecule of glucose. Species C produces more carbon dioxide than does Species B.arrow_forward
- Biology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage Learning