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This is a 3D model of a DNA molecule. It is made up of two strands that form a double helix. If we unwind the helix, we can see that each strand is a chain of building blocks called nucleotides. Le...

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Dengue virus is an RNA virus. Its outer surface is covered with envelope proteins surrounding a lipid bilayer envelope. Inside the envelope is a capsid shell that contains the virus’s RNA genome. Immu...

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Alright so now we're going to go into a little bit more detail on Dengue virus since it's once the subjects of our talk today. If you rotate it very carefully, I'm going to highlight for you the penta...

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Like all young mammals, human infants depend on milk for nutrition. Milk is rich in lactose, a disaccharide made from two sugar molecules. Lactose cannot be directly absorbed in the small intestine. T...

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Mutations arise at random in a population. Suppose a mutation arises that causes adults to produce lactase in a population that doesn't have any dairy cows. Adults don't drink milk, so producing the l...

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Polymerase chain reaction-- or PCR-- uses repeated cycles of heating and cooling to make many copies of a specific region of DNA. First, the temperature is raised to near boiling, causing the double s...

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So this squid is a nocturnal animal. And so what we've done is we put this poor guy in his water during the day. And he doesn't like it. So he looks kind of uncoordinated, he looks a...

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Books and arts. Books review. Ernest Hemingway's Biography. The old man and the sea. Hemingway’s Boat: Everything He Loved in Life, and Lost, 1934-1961. By Paul Hendrickson. Paul Hendrickson bibli...

书籍和艺术 书评 欧内斯特·海明威的传记 老人与海 《海明威的船：他生命中所热爱的一切，失去的一切，1934-1961》; 作者：保罗·亨德里克森 保罗·亨德里克森传记的参考目录中列举了76部关于海明威的传记作品，其中9部...