l Give several pieces of evidence that RNA preceded proteins

l) Give several pieces of evidence that RNA preceded proteins and DNA in living things 2) Do your answers to (1) mean that the first life was RNA-based, with RNA serving as both the catalyst and the genetic material Briefly discuss the strengths and weaknesses of this hypothesis. 3) It is believed that the machinery for photosynthesis evolved only once, in the cyanobacteria. However, several unrelated groups of eukaryotes, such as green plants, diatoms, and euglenoids, are able to photosynthesize. How can this be explained? 4) Answer each question True or False TVF). f the answer is false, explain why. Eukaryotic cells are more similar to archaea for genes involved in protein synthesis and DNA replication, but more similar to bacteria for genes involved in metabolism RNA has been found in meteorites, and was produced in the Miller-Urey experiment, giving evidence supporting the \"RNA-first\" hypothesis of the origin of life. The last universal common ancestor of all living things lived less than 2 billion years ago. The first living things required oxygen (O2) The 12C C ratio is higher in living things than in atmospheric CO2 5) Which of the following is your closest relative? Your second closest? a) a fungus; b) a dinoflagellate; c) a pine tree; d) a choanoflagellate; e) aciliate; an archaean 6) Why are marine organisms relatively common in the fossil record, but mountain-dwelling species relatively rare?

Solution

(5) on the basis of events by examining, cell adhesion, communication and development

choanoflagellate are the closest to us as they express some kind of same protein for cell adhesion as in animals although choanoflagellate is unicellular.

than second closest is fungus and than archaean, ciliate, dinoflagellate & pine tree respectively.

(6) mostly, mountains are made from many layers of marine dead things which are consumed soner or later after they die over millions of year by vertical placement of layers in particular location. so marine organism are more commonly found than mountain dwelling species.

Only rarely do properties of the organism and environmental conditions promote fossilization. To become a fossil, it helps to have- hard body parts,a rapid burial, protection from scavengers/bacteria, protection from oxygen.