 Hey everybody! We're back for part two of our three-part exploration of DNA structure and function and application in the next lecture. Today's topic is how DNA works. In the last lecture we looked at its structure, we looked at how it replicates, how it makes a copy of itself, and this picture that I've sort of reworked to make it a little less messy. This picture of a human life cycle sort of put context in why we would need to replicate DNA in the first place. Today we're looking at why DNA is so important and it's so important because of its function in providing the instructions for building the proteins. I want to just take a second to remind you of our life cycle and sort of talk through like where does today's stuff happen. DNA replication happens every single time mitosis and meiosis occur. We make copies of the DNA so that when our cells divide to make more cells, each cell has a complete copy of all the DNA that you need. DNA function is about the cell producing the proteins that it needs to function and that those instructions come from the nucleus in the DNA. A couple of words that I want to just put on our list and expose us to now. Your genotype is your genetic code. It's your genes. It's the the information that's carried in your DNA. That's your genotype and that's opposed to so every single cell contains everything that you need to know about your genotype. It's opposed to phenotype. I always think of phenotype as what you look like but it's actually the expression of the genes. So it's the proteins that get built from the DNA. That's our topic. How do proteins get produced from DNA? How does the DNA, the genotype, code for the proteins that cause your phenotype, what you look like, the physical traits that you can actually see and observe in an organism? Our genetic code gives us this information. Okay, first up we're going to talk about the central dogma of biology because it summarizes the whole process of protein synthesis or DNA function.