Chapter 8.1: Basic Definitions and Conventions

• Nucleotides used as energy currency in metabolic transactions, essential chemical links in the response of cells to hormones and other extracellular stimuli, structural components of an array of enzyme cofactors and metabolic intermediates, and constituents of nucleic acids.
• Nucleic acids are both repositories and functional expressions of biological information.
• Biological information is one of the required conditions for life, a blueprint for each species transmitted from one generation to the next.
• RNA can be a functional expression of biological information, directing the synthesis of proteins, or, in some cases, acting directly as a signal or a reaction catalyst.
• The transmission of biological information relies on molecular complementarity.
• Chromosomes are the largest molecules in any cell.
• Chromosomes are polymers composed of a small set of common nucleotides, with information embedded in the nucleotide sequence.
• The most common nucleotides in RNA and DNA are organized so that two strands of nucleic acid can maintain a complementary and uniform structure over vast molecular distances.
• The extended potential for both variable sequence and complementarity, and thus information storage and transmission, is a property shared by no other class of biological molecule.
• Biological information is subject to natural damage and change.
• DNA damage is a constant, and it results in occasional mutations, the raw material for evolution.
• Biological information can be accessed, interpreted, and altered in the laboratory.
• The information embedded in nucleic acids is of singular importance to biochemistry and molecular biology.
• The techniques for sequencing, synthesizing, and altering nucleic acids are continually advancing.
• Nucleoside triphosphates occupy a central role in cellular metabolism, serving as an energy currency and as important regulatory signals.
• ATP is the ultimate product of catabolic pathways, providing fuel for anabolic pathways.
• A gene is a segment of a DNA molecule that contains the information required for the synthesis of a functional biological product, whether protein or RNA.
• The only known functions of DNA are the storage biological information and the transmission of that information to the next generation.
• The classes of RNA are ribosomal RNA, messenger RNA, transfer RNA, and noncoding RNA.
• Ribosomal RNA, rRNA, are the components of ribosomes.
• Messenger RNA, mRNA, are the intermediates in protein synthesis.
• Transfer RNA, tRNA, is an adapter molecule that translates the information in mRNA into a specific amino acid sequence.
• Noncoding RNA, ncRNA, has a wide variety of functions.
• The three components of nucleotides are a nitrogenous base, a pentose, and one or more phosphate groups.
• The nitrogenous bases are either pyrimidines or purines.
• A nucleoside is the molecule without a phosphate group.
• Another name for a nucleotide is a nucleoside phosphate.
• The N-beta-glycosyl bond covalently joins the 1' carbon of the pentose to the base.
• The N-beta-glycosyl is at the N 1 of pyrimidines and N 9 of purines.
• N-beta-glycosyl bonds are formed by the removal of the elements of water.
• The phosphate group is esterified to the 5' carbon.
• The major purine bases are adenine and guanine.
• Adenine is in DNA and RNA.
• Guanine is in DNA and RNA.
• The major pyrimidine bases are cytosine, thymine, and uracil.
• Cytosine is in DNA and RNA.
• Thymine is only in DNA.
• Uracil is only in RNA.
• Adenine

  
• Cytosine