Nucleic Acids

Cards (101)

  • Nucleic acids
    Polymeric molecules in which the repeating units are nucleotides
  • Types of nucleic acids
    • Deoxyribonucleic acids (DNA)
    • Ribonucleic acids (RNA)
  • Functions of DNA and RNA
    DNA - transfer of genetic information
    RNA - synthesis of proteins
  • Nucleic acid building blocks
    • Pentose sugar (ribose or deoxyribose)
    Nitrogen-containing base (purine or pyrimidine derivative)
    Phosphate group
  • Nitrogen-containing bases
    • Adenine (A)
    Guanine (G)
    Cytosine (C)
    Thymine (T)
    Uracil (U)
  • Nucleoside
    Compound formed from a pentose sugar and a purine or pyrimidine base derivative
  • Nucleotide
    Nucleoside to which a phosphate group has been added
  • Nucleotide
    Monomers for nucleic acid polymers
  • Primary nucleic acid structure
    Backbone is a constant alternating sequence of sugar and phosphate groups, with a nitrogen-containing base attached to each sugar unit
  • Complementary bases
    Specific pairs of bases in nucleic acid structures that hydrogen-bond to each other
  • Secondary DNA structure
    Two polynucleotide chains coiled around each other in a double-helix arrangement, held together by hydrogen bonding between complementary pairs of bases (A with T, C with G)
  • DNA replication
    Two strands of a parent DNA double helix separate and act as templates for the synthesis of new chains using the principle of complementary base pairing
  • Chromosome
    Structure consisting of an individual DNA molecule bound to a group of proteins
  • Types of RNA molecules

    • Ribosomal RNA (rRNA)
    Messenger RNA (mRNA)
    Heterogeneous nuclear RNA (hnRNA)
    Transfer RNA (tRNA)
    Small nuclear RNA (snRNA)
  • Transcription
    Genetic information encoded in the base sequence of DNA is copied into hnRNA/mRNA molecules
  • Gene
    Portion of a DNA molecule that contains the base sequences needed for the production of a specific hnRNA/mRNA molecule, with exons containing genetic information and introns not conveying genetic information
  • Codon
    Three-nucleotide sequence in mRNA that codes for a specific amino acid needed during protein synthesis
  • Genetic code

    All the mRNA codons that specify either a particular amino acid or the termination of protein synthesis
  • Anticodon
    Three-nucleotide sequence in tRNA that binds to a complementary sequence (a codon) in mRNA
  • Translation
    Codons in mRNA are translated into amino acid sequences of new proteins, involving interactions between the codons of mRNA and the anticodons of tRNA
  • Types of mutations
    • Point mutation - one base in a DNA sequence is replaced with another base
    Frameshift mutation - insertion or replacement of a base in a DNA sequence
  • Recombinant DNA
    Synthesized by splicing a segment of DNA, usually a gene, from one organism into the DNA of another organism
  • Polymerase chain reaction

    Method for rapidly producing many copies of a DNA sequence
  • Nucleoside
    A two-subunit molecule in which a pentose sugar is bonded to a nitrogen containing heterocyclic base
  • Nucleoside formation
    1. Base
    2. Sugar
    3. Water
  • Nucleoside formation
    • The base is always attached to C1' of the sugar (the anomeric carbon atom) in a β-configuration
    • For purines, attachment is through N9; for pyrimidines, N1 is involved
    • A molecule of water is formed as the two molecules bond together
  • RNA nucleosides
    • ribose-adenine
    • ribose-cytosine
    • ribose-guanine
    • ribose-uracil
  • DNA nucleosides
    • deoxyribose-adenine
    • deoxyribose-cytosine
    • deoxyribose-guanine
    • deoxyribose-thymine
  • Nucleoside naming
    Pyrimidine bases use the suffix -idine
    Purine bases use the suffix -osine
    The prefix deoxy- indicates deoxyribose sugar
  • Nucleotide
    A nucleoside with a phosphate group bonded to the pentose sugar
  • Nucleotide formation
    1. Nucleoside
    2. Phosphate group
    3. Water
  • Nucleotide formation
    • The phosphate group is attached to the sugar at the C5' position through a phosphoester linkage
    • A molecule of water is produced in the process
  • Nucleotides
    • Adenosine 5'-monophosphate (AMP)
    Guanosine 5'-monophosphate (GMP)
    Cytidine 5'-monophosphate (CMP)
    Uridine 5'-monophosphate (UMP)
    Deoxyadenosine 5'-monophosphate (dAMP)
    Deoxycytidine 5'-monophosphate (dCMP)
    Deoxyguanosine 5'-monophosphate (dGMP)
    Deoxythymidine 5'-monophosphate (dTMP)
  • Ribonucleic Acid (RNA)

    A nucleotide polymer in which each of the monomers contains ribose, phosphate group, and one the heterocyclic bases: adenine, guanine, cytosine, or uracil
  • Deoxyribonucleic Acid (DNA)

    A nucleotide polymer in which some of the monomers contain deoxyribose, phosphate group and one of the heterocyclic bases: adenine, guanine, cytosine and thymine
  • Nucleic Acid Backbone
    • The alternating sugar-phosphate chain in nucleic acid structure
    • Constant through the entire nucleic acid structure
    • For DNA molecules, it consist of alternating phosphate and deoxyribose sugar units
    • For RNA molecules, it consists of alternating phosphate and ribose sugar units
  • Primary Nucleic Acid Structure
    • The sequence in which nucleotides are linked together in a nucleic acid
    • Depends only on the sequence of bases present
  • Important Points about Nucleic Acid Structure
    • Each nonterminal phosphate group of the sugar-phosphate backbone is bonded to sugar molecules through a 3',5'-phosphodiester linkage
    • A nucleotide chain has directionality. The 5'end normally carries a free phosphate group attached to the 5' carbon atom. The 3' end normally has a free hydroxyl group attached to the 3' carbon atom
    • Each nonterminal phosphate group in the backbone of a nucleic acid carries a 1- charge
  • DNA Double Helix
    • Involves two polynucleotide strands coiled around each other in a manner similar to a spiral staircase
    • The sugar-phosphate backbone as the outside banisters of the spiral staircase
    • The bases (side chains) extend inward toward the bases of the other strand
    • The two strands are connected by hydrogen bonds between their bases
    • The two strands is antiparallel–as they run in opposite direction: one runs in the 5' to 3' direction, the other runs in 3' to 5' direction
    • Two strands of DNA in a double helix are not identical —they are complementary
  • Base Pairing
    • One small base (a pyrimidine) and one large base (a purine)
    • Most favorable combinations that normally occur in DNA are the A–T and G—C pairing