1.How did the nucleus evolve? 2.What are the pointers indicating the evolution of eukaryotes from the same branch as archea? 3.Obligate anaerobes, what is the end products? Does it include molecular oxygen? What is it in case of facultative anaerobes? Is there any organism that uses a substrate, which unlike nitrates, sulfates, carbondioxide etc.! does not contain oxygen? *Lithotrophs oxidising HS- to S0 have a oxygen less substrate 4.Cell shape and rigidity conferred by cell wall or peptidoglycan layer when both are present? 5.Bacterial ribosomes are smaller than the eukaryotic ribosomes? So what is the function of the larger region? Why is it comparitively larger? What are the advantages conferred? 6.How did the plasmids evolve? What are the available theories? Only a few confer antibiotic and toxin resistance, what about those that dont? 7. How is the density gradient established in isopycnic centrifugation? Wont diffusion render the gradient useless in a short time? 8. What are motor proteins? How do they act (apart from actin and myosin)? Which book is good for information about these? 9. If the interactions between the organelles and the cytoskeleton are noncovalent, how is it regulated? Only way I can think of is change in pH(which inturn can influence things like hydrogen bonding, extent of vanderwaals forces, dipole dipole interaction, electrostatic interactions etc., )! What are the other ways, apart from pH regulation if at all, the cell uses to regulate this? 10. How is the varied cytosolic composition within a cell regulated? I mean it is the fundamental level where the controlling factor cannot be a large molecule because its presence in itself will have an influence on the composition, so is it like the rate of production and degradation of various substances in various parts of the cell are varied and since it is a dynamic and continuos process, there is no time for establishment of equillibrium of substance concentration? 11. It ia common notion that All cells have nucleus for some part of their life. Are there no structurss that appear similar to cells but have never had a nucleus? I mean like cytokinesis without nucleokinesis(similar to vesicle budding from an organelle)? N wouldnt it be more efficient to have rbc produced like this? A master cell with nucleus producing enzymes needed and a part of the cell chipping off? (Just wondering even though am aware these things are based on evolutionary selection) These are the doubts that struck me as I read my first chapter in biochemistry in lehninger. Hope you people can help me with these and also that you find atleast a few interesting! Thanks in advance people!!!