BSC 196 Lecture Notes - Lecture 11: Endoplasmic Reticulum, Nuclear Membrane, Cytoskeleton
Document Summary
Chemical and physical processes on early earth may have produced simple cells through 4 stages. Abiotic synthesis of small organic molecules amino acids, nitrogenous bases. Joining of these small molecules into macromolecules proteins, nucleic acids. Packaging of molecules into protocells membrane-bound droplets with different internal chemistry. In the 1920s, a. i. oparin and j. Rna monomers (nucleotides) have been produced spontaneously from simple molecules. Rna molecules called ribozymes have been found to catalyze many different reactions (1982 led to nobel prize) ribozymes also can make complementary copies of short stretches of rna early genetic material formed an (cid:862)rna-(cid:271)ased (cid:449)orld(cid:863) Rna molecules that were more stable or replicated more quickly would have left the most descendant rna molecules (i. e. , natural selection) Vesicles containing rna capable of replication may have have been first protocells. Rna could have provided the template for dna, a more stable genetic material. The fossil record shows changes in kinds of organisms on earth over time.
