Tutor profile: Nicole N.
What is the total electron configuration of gold (AU)? How can this be expressed as a noble gas configuration?
The total electron configuration is: 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106s1 The noble gas configuration is: [Xe] 6s24f145d106s1
Lipid rafts are often necessary in order to have a strong insulin signal. One important characteristic of lipid rafts is its high concentration of cholesterol. Explain the role of cholesterol in the membrane raft and explain how it relates to insulin signaling.
Cholesterol’s main function in regards to lipid rafts is to provide stability. It separates the raft portion from the nonraft portion, having a higher affinity for sphingolipids than other phosopholipids. These two molecules provide a stable portion of the membrane to receive such molecules as the signal proteins to increase the rate of the signal cascade.
Explain the suggested relationship between birds and dinosaurs. Give examples of how they are similar.
Fossil evidence has supported a close relationship between birds and dinosaurs. Externally, several dinosaur skeletons have been found with preserved feathers. Internally, all birds and many dinosaurs have pneumatized bones and gizzard stones. Both build nests to lay their amniotic eggs. It has also been found that some dinosaurs contained hollow sacs which is very unique to birds’ efficient respiratory system. Evolutionary, it is thought that dinosaurs came from the same ancestor as birds and crocodiles which contain a diapsid skull. An important link was the discovery of the ancient Archeopteryx which contain features unique to birds and features unique to reptiles.
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