Transcript Slide 1
Cell Evolution In the beginning • Earth 4.6BYA • First life 3.5 BYA. Protocells- Chains of amino acids that form a membrane • Protocells cannot grow, reproduce, metabolize. • Macromolecule that makes up all cells plasma membrane? • Phospholipids. In water. Anaerobic Prokaryotes • 3.9-3.5 BYA, No free oxygen • Energy through fermentation or gylcolysis (anaerobic) • Glucose (Broken down to) →Energy (ATP) + Ethanol + Carbon dioxide (CO2) • Glucose (Broken down to) →Energy (ATP) + Lactic acid Archaebacteria Live in harsh conditions • Autotrophic • Chemosynthesis= use chemicals to make E (sulfer) Photosynthetic Prokaryotes • Cyanobacteria • Put oxygen into atmosphere • Makes aerobic respiration possible (break down molecules using oxygen) • Made the ozone • Increased oxygen from far less than 1% to about 20% Aerobic Prokaryotes • With oxygen bacteria can use oxygen to make energy • Aerobic is more efficient than anaerobic respiration. • Glucose + Oxygen →Energy + Carbon dioxide + Water • Net ATPs produced – Anaerobic: 2 ATP – Aerobic: 36 ATP Endosymbiotic Theory • Eukaryotic cells formed from a symbiosis among several different prokaryotes. • Eukaryotic cells arose from living communities formed by prokaryotic organisms. Origin of Eukaryotic Cells Aerobic bacteria Ancient Prokaryotes Nuclear envelope evolving Ancient Anaerobic Prokaryote Origin of Eukaryotic Cells Mitochondrion • Prokaryotes that use oxygen to generate energyrich molecules of ATP evolved into mitochondria. Primitive Aerobic Eukaryote Origin of Eukaryotic Cells Prokaryotes that carried out photosynthesis evolved into chloroplasts. Chloroplast Photosynthetic bacteria Primitive Photosynthetic Eukaryote Evidence of Endosymbiotic Theory • Cyano VS. chloroplast • Look alike • Both perform Photsynthesis • DNA in both is similar • Ribosomes are similar • Chloroplasts can divide on own • Mito vs. aerobic bacteria • Look alike • Heterotrophs that perform aerobic resp. • DNA is similar • Ribosomes are similar • Mito divide on own If it looks, acts, and sounds like a duck Ancient Prokaryotes Chloroplast Aerobic bacteria Nuclear envelope evolving Ancient Anaerobic Prokaryote Photosynthetic bacteria Plants and plantlike protists Mitochondrion Primitive Aerobic Eukaryote Primitive Photosynthetic Eukaryote Animals, fungi, and non-plantlike protists