Nucleic Acids Flashcards
Nucleotide
The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and one or more phosphate groups
Antiparallel
Referring to the arrangement of the sugar-phosphate backbones in a DNA double helix (they run in opposite 5’ - 3’ directions)
DNA
Deoxyribonucleic acid.
A double-stranded, helical nucleic acid molecule, consisting of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T); capable of being replicated and determining the inherited structure of a cell’s proteins
RNA
Ribonucleic acid.
A type of nucleic acid consisting of a polynucleotide made up of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually single-stranded; functions in protein synthesis, gene regulation, and as the genome of some viruses
Polynucleotide
A polymer consisting of many nucleotide monomers in a chain. The nucleotides can be those of DNA or RN
Purine
One of two types of nitrogenous bases found in nucleotides, characterised by a six-membered ring fused to a five-membered ring. Adenine (A) and guanine (G) are purines
Pyrimidine
One of two types of nitrogenous bases found in nucleotides, characterised by a six-membered ring. Cytosine (C), thymine (T), and uracil (U) are pyrimidines
Nucleoside
In a polynucleotide, each monomer has only one phosphate group. The portion of a nucleotide without any phosphate groups is called a nucleoside
Nitrogenous base
Each nitrogenous base of a nucleotide has one or two rings that contain nitrogen atoms (called bases because the nitrogen atoms tend to take up H+).
Can be either a pyrimidine (cytosine C, thymine T, and uracil C). Or purine (adenine A, and guanine G).
Double helix
DNA molecules have two polynucleotides, or “strands” that spiral around an imaginary axis, forming a double helix.
DNA structure
Each DNA nucleotide consists of a nitrogenous base (T, A, C, or G), the sugar deoxyribose and a phosphate group.
Adenine pairs with thymine (A with T) and guanine pairs with cytosine (G with C)
Pentose sugars
In DNA the sugar is deoxyribose. In RNA it is ribose. The only difference between these two sugars is that deoxyribose lacks an oxygen atom on the second carbon in the ring; hence the name deoxyribose.
