Nucleotides and nucleic Acids 11/05/2002 Bing zhou, PhD Department of Biological Science and Biotechnology TSinghua University
Nucleotides and Nucleic Acids 11/05/2002 Bing Zhou, PhD Department of Biological Science and Biotechnology Tsinghua University
Functions of Nucleotides RNA and DNA components serving as energy stores for future use in phosphate transfer reactions. These reactions are predominantly carried out by ATP forming a portion of several important coenzymes such as NAD+, NADP+, FAD and coenzyme A second messengers in signal transduction events. The predominant second messenger is cyclic-AMP(CAMP), a cyclic derivative of amp formed from atp controlling numerous enzymatic reactions through allosteric effects on enzyme activity. serving as activated intermediates in numerous biosynthetic reactions. These activated intermediates include s- adenosylmethionine(s-AdoMet) involved in methyl transfer reactions as well as the many sugar coupled nucleotides involved in glycogen and glycoprotein synthesis
Functions of Nucleotides ► RNA and DNA components ► serving as energy stores for future use in phosphate transfer reactions. These reactions are predominantly carried out by ATP. ► forming a portion of several important coenzymes such as NAD+, NADP+, FAD and coenzyme A. ► second messengers in signal transduction events. The predominant second messenger is cyclic-AMP (cAMP), a cyclic derivative of AMP formed from ATP. ► controlling numerous enzymatic reactions through allosteric effects on enzyme activity. ► serving as activated intermediates in numerous biosynthetic reactions. These activated intermediates include Sadenosylmethionine (S-AdoMet) involved in methyl transfer reactions as well as the many sugar coupled nucleotides involved in glycogen and glycoprotein synthesis
DNA as Genetic Material
DNA as Genetic Material
History of DNA 1. The Swiss biologist, Friedrich Miescher, isolated DNA from salmon sperm in 1868 2. In 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that DNA from pathogenic strains of the bacterium Pneumococcus could be transferred into nonpathogenic strains, making them(and any succeeding generations) 3. Erwin Chargaff reported in 1947 that the quantitities of adenine and thymine in dNa were very close to the same value. Similarly, he observed that cytosine and guanine were also very close to equal in quantity. 4. In 1952, Alfred Hershey and Martha Chase showed T2 bacteriophage inject only DNA into cells and this is sufficient to make more T2 bacteriophage 5. James Watson and Francis Crick proposed the model of the double helix of dna in 1953 6. In 1965, Marshall Nirenburg, Philip Leder, and others, identified the genetic code by which protein is made from information in DNA
History of DNA ► 1. The Swiss biologist, Friedrich Miescher, isolated DNA from salmon sperm in 1868. ► 2. In 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that DNA from pathogenic strains of the bacterium Pneumococcus could be transferred into nonpathogenic strains, making them (and any succeeding generations) pathogenic ► 3. Erwin Chargaff reported in 1947 that the quantitities of adenine and thymine in DNA were very close to the same value. Similarly, he observed that cytosine and guanine were also very close to equal in quantity. ► 4. In 1952, Alfred Hershey and Martha Chase showed T2 bacteriophage inject only DNA into cells and this is sufficient to make more T2 bacteriophage. ► 5. James Watson and Francis Crick proposed the model of the double helix of DNA in 1953. ► 6. In 1965, Marshall Nirenburg, Philip Leder, and others, identified the genetic code by which protein is made from information in DNA
Levene(1910)-tetranucleotide hypothesis nucleic acid is a repetitive polymer of four subunits A: C: G: T in the ratio 1: 1:1:1 structure seems too simple to carry information
Levene (1910) - tetranucleotide hypothesis nucleic acid is a repetitive polymer of four subunits A:C:G:T in the ratio 1:1:1:1 => structure seems too simple to carry information