Lecture 27Outline of Last Lecture1) Explain how DNA is (a) bidirectional and (b) discontinuous in one strand and continuous in the other. What is an Okasaki Fragment and why is it needed?2) What does it mean to say that DNA synthesis is semi-conservative? 3) Why do cells have DNA repair enzymes?4) Define telomere; describe the possible connections between telomerase and cell aging and between telomerase and cancer.5) Who are these DNA pioneers and what was their claim to fame as scientists? Watson and Crick, Rosalind Franklin, Hershey and Chase, Erwin Chargaf. Optional: Griffith, Avery, Meselson and Stahl.Outline of Current Lecture(1) Summarize the early evidence indicating that most genes specify the structure of proteins.(2) Outline the flow of genetic information in cells, from DNA to protein.(3) Compare the structures of DNA and RNA.(4) Explain why the genetic code is said to be redundant and virtually universal.(5) Compare the processes of transcription and DNA replication, identifying both similarities and differences.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. BIOL 101 1st EditionI. Gene Protein Evidence- 1920; metabolic errors were proposed to be inherited. Using this knowledge, Linus Pauling in 1949 proposed a genetic relationship between sickle cell hemoglobin and the sickle celltrait, hemoglobin being a very important protein in blood cells. He proved it since the only way hemoglobin can be synthesized is by instructions from the DNA, and if the DNA is instructed with sickle cell hemoglobin, it changes accordingly.II. DNA -> Protein Steps- DNA is transcribed into RNA in the nucleus, and the RNA is shot out into the cytoplasm, where it is picked up by ribosomes on the rough ER that translate the RNA informationinto proteins.- The RNA has a sequence of nucleotides in a specific order thatthe ribosomes read, and every combination of 3 nucleotides adds on amino acids in a specific order, going on until it reaches a stop, thus creating a protein.III. DNA & RNA Structure- There is one difference in structure between DNA and RNA: anoxygen. That’s it. DNA is deoxyribonucleic acid and RNA is ribonucleic acid. DNA has one less oxygen than RNA, and that is the only difference in structure.IV. Universitile and Redundant- DNA is universal because every organism on earth uses the same sequence of nucleotides and DNA structure. The redundancy comes from the large amount of repetition in nucleotides; the same codons repeating.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. BIOL 101 1st EditionV. DNA Replication, RNA Transcription- DNA replication and RNA transcription aren’t really something you compare. The only real similarity is that a replication fork is made. In DNA replication, DNA is synthesized through the fork, but in RNA transcription, the nucleotides are read and specific nucleotides are put into place according to what’s on the DNA. Then it’s just totally different process.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. BIOL 101 1st
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