Evolution of Prokaryotes, Eukaryotes, and Viruses PDF

L1B: EVOLUTION OF PROKARYOTES, EUKARYOTES, AND VIRUSES OUTLINE I. II. III. IV. A. Prokaryotes vs Eukaryotes Evolution of Prokaryotes A. Miller’s Experiment B. Genetic Material and Lipids Evolution of Eukaryotes A. Endosymbiosis B. Multicellularity Evolution of Viruses ○ HISTORY OF CELLULAR AND M...

L1B: EVOLUTION OF PROKARYOTES, EUKARYOTES, AND VIRUSES OUTLINE I. II. III. IV. A. Prokaryotes vs Eukaryotes Evolution of Prokaryotes A. Miller’s Experiment B. Genetic Material and Lipids Evolution of Eukaryotes A. Endosymbiosis B. Multicellularity Evolution of Viruses ○ HISTORY OF CELLULAR AND MOLECULAR BIOLOGY Table No. Prokaryotes VS Eukaryotes PROKARYOTES EUKARYOTES Without nucleus Contain nucleus (and organelles) Circular DNA Linear or segmented DNA Domains: Kingdoms: ● Archaea ● Animalia ● Bacteria ● Plantae ● Fungi ● Protista ● EVOLUTION OF PROKARYOTES Self-replication of RNA ■ Complementary pairing between nucleotides (adenine [A] with urinal [U] and guanine [G] with cytosine [C] allows one strand of RNA to serve as a template for the synthesis of a new strand with the complementary sequence. Lipid membrane ○ ○ First cell structure to develop Lipid membrane are composed of phospholipid bilayer ■ Amphipathic How it formed: ■ When water and lipid are vigorously mixed micelles (1 layer) and liposomes (2 layers) spontaneously form. ■ By chance, RNA becomes enclosed in these lipid membranes, which allowed them to be maintained as one unit. ○ THE EVOLUTION OF METABOLISM ● ● Miller’s Experiment ○ Spontaneous formation of organic molecules ○ Atmospheric Gases on Earth: CO2, N; H2, H2S and CO ○ Miller’s Experiment ■ Produced H2, CH4, NH3, and some amino acids ■ Demonstrated that monomers can polymerize spontaneously under plausible prebiotic conditions ○ Characteristics of the first polymer formed: 1. Capable to self-replicate 2. Be a catalyst themselves ○ What macromolecule can perform these 2 characteristics? RNA, the first macromolecule RNA ● ● Adenosine Triphosphate (ATP) = energy Metabolism - the chemical processes involved in the production of ATP ● Metabolic Pathways (in order): A. Glycolysis - ubiquitous process ○ Because only primordial gases are present ○ Can occur in the absence of oxygen (aerobic conditions) B. Photosynthesis ○ May have developed during the oxygenation of the Earth ○ Production of Oxygen resulted in the formation of the ozone layer C. Oxidative Metabolism ○ Cellular respiration LAGRASON, LIECA ANGELINE L. | BS BIOLOGY 3 ○ Used and requires oxygen ○ EVOLUTION OF EUKARYOTES ○ Algae have both multicellular and unicellular species An amoeba Dictyostelium discoideum can transition from unicellular to multicellular ■ Depending on the environment EVOLUTION OF VIRUSES ● ● ● Virus ○ ○ Not considered as living organisms Obligate intracellular parasites ■ Requires a host ○ Found in DNA ○ Lacks the cellular machineries necessary to replicate Virus has existed for a long period of time ○ Retoriviral cDNA is found in 5-8% of ○ Proof: visual representation of polio in artifacts Believe to arose from the branch of Archaea ○ From the endosymbiotic relationship of bacteria and archaea ○ Proof: first cell has similar metabolism with the archaea ENDOSYMBIOSIS ● ● ● Mitochondria and Chloroplasts are theorized as previous aerobic bacteria and photosynthetic bacteria, respectively ○ Archaea - same metabolism ○ Bacteria - has own cell membrane Mitochondria ○ Has own DNA ○ Has 2 cell membrane ○ Same size as bacteria Why? MULTICELLULARITY ● Nucleus and other organelles ○ Invagination Hypothesis ● Unicellular to multicellular ○ Occurred Multiple Time in Nature ● May have existed before life ● Simple structure: ○ Genetic Material (DNA or RNA) ○ Proteins (capsid) ○ Envelope (Lipid Membrane) ■ May or may not be present Reductive evolution ○ Giant viruses ■ Its size can be phagocytosed ■ Encodes for translating genes ■ Contains protein information (genetic code) from prokaryotes that it doesn’t use ■ Said to come from prokaryotes but it discarded unnecessary parts and devolved into a virus instead. ● LAGRASON, LIECA ANGELINE L. | BS BIOLOGY 4