What is composed of a five-carbon sugar a phosphate group and a nitrogenous base?
A five-carbon sugar with a phosphate group and a nitrogenous base is comprised on two elements. This includes a nucleic acid and DNA, deoxyribonuleic acid.
A nucleotide is composed of: 1.) A nitrogenous base (either a purine such as Adenine or Guanine, or a pyrimidine such as a Thymine or Cytosine; Uracil is the nitrogenous base that replaces Thymine in RNA) 2.) A ribose sugar (5 Carbon ring) 3.) A phosphate group The nitrogenous base is attached to Carbon 1 on the ribose sugar while the phosphate group is attached to Carbon 5 of the same sugar. (That same phosphate…
A nucleoside (with an s) is a nitrogenous base covalently attached to a (ribose or deoxyribose) sugar but does not have a phosphate group attached. A nucleotide (with a t) consists of a nitrogenous base, a sugar, and a phosphate group. So, a nucleotide is a "nucleoside mono-phosphate" or a nucleoside with a phosphate group attached.
First off - it is important to understand that a nucleotide (the monomer of DNA) is composed of 3 things: a sugar, a phosphate group, and a nitrogenous base. Next - understand that the "backbone" of DNA is composed of the sugars and phosphates. That leaves you with nitrogenous bases. Hydrogen bonds form between the nitrogenous bases off opposite strands in the double helix. THIS is what holds the double helix together.