Genetics acid

Watson J D and Crick F H C 1953 Genetical implications of the structure of deoxyribonucleic acid Nature 171 964-7... 

Klapper 1, R Hagstrom, RFine, K Sharp and B Honig 1986. Focusing of Electric Fields in tire Actir e Sit of CuZn Superoxide Dismutase Effects of Ionic Strength and Amino-Acid Substitution. Proteins Structure, Function and Genetics 1 47-59. 

The major classes of organic compounds common to living systems are lipids pro terns nucleic acids and carbohydrates Carbohydrates are very familiar to us— we call many of them sugars They make up a substantial portion of the food we eat and provide most of the energy that keeps the human engine running Carbohy drates are structural components of the walls of plant cells and the wood of trees Genetic information is stored and transferred by way of nucleic acids specialized derivatives of carbohydrates which we 11 examine m more detail m Chapter 28... 

The hydroxyl at C 2 m D nbose is absent m 2 deoxy d nbose In Chapter 28 we shall see how derivatives of 2 deoxy d nbose called deoxynbonucleotides are the funda mental building blocks of deoxyribonucleic acid (DNA) the material responsible for stor mg genetic information L Rhamnose is a compound isolated from a number of plants Its carbon chain terminates m a methyl rather than a CH2OH group... 

In Chapter 1 we saw that a major achievement of the first half of the twentieth cen tury was the picture of atomic and molecular structure revealed by quantum mechan ICS In this the last chapter we examine the major achievement of the second half of that century—a molecular view of genetics based on the structure and biochemistry of nucleic acids... 

Nucleic acids are acidic substances present m the nuclei of cells and were known long before anyone suspected they were the primary substances involved m the storage transmission and processing of genetic information There are two kinds of nucleic acids ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) Both are complicated biopolymers based on three structural units a carbohydrate a phosphate ester linkage between carbohydrates and a heterocyclic aromatic compound The heterocyclic aro matic compounds are referred to as purine and pyrimidine bases We 11 begin with them and follow the structural thread... 

True to their word Watson and Crick followed up their April 25 paper with another on May 30 This second paper Genetical Implications of the Struc ture of Deoxyribonucleic Acid outlines a mechanism for DNA replication that is still accepted as essentially correct... 

The genetic code (Table 28 3) is the message earned by mRNA It is made up of triplets of adjacent nucleotide bases called codons Because mRNA has only four dif ferent bases and 20 ammo acids must be coded for codes using either one or two nucleotides per ammo acid are inadequate If nucleotides are read m sets of three how ever the four mRNA bases generate 64 possible words more than sufficent to code for 20 ammo acids... 

Section 28 11 Three RNAs are involved m gene expression In the transcription phase a strand of messenger RNA (mRNA) is synthesized from a DNA tern plate The four bases A G C and U taken three at a time generate 64 possible combinations called codons These 64 codons comprise the genetic code and code for the 20 ammo acids found m proteins plus start and stop signals The mRNA sequence is translated into a prescribed protein sequence at the ribosomes There small polynucleotides called... 

DNA (deoxyribonucleic acid) (Section 28 7) A polynucleotide of 2 deoxynbose present in the nuclei of cells that serves to store and replicate genetic information Genes are DNA... 

New Chapter 28 Nucleosides Nucleotides and Nucleic Acids is new Its presence testifies to the importance of these topics and the explosive growth of our knowledge of the molecular basis of genetics... 

Several aspects affect the extent and character of taste and smell. People differ considerably in sensitivity and appreciation of smell and taste, and there is lack of a common language to describe smell and taste experiences. A hereditary or genetic factor may cause a variation between individual reactions, eg, phenylthiourea causes a bitter taste sensation which may not be perceptible to certain people whose general abiUty to distinguish other tastes is not noticeably impaired (17). The variation of pH in saUva, which acts as a buffer and the charge carrier for the depolarization of the taste cell, may influence the perception of acidity differently in people (15,18). Enzymes in saUva can cause rapid chemical changes in basic food ingredients, such as proteins and carbohydrates, with variable effects on the individual. 

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