DNA structure :three components:a nitrogenous base,a sugar and a phosphate.
Primary structure of DNA
A polynucleotide chain consists of a series of 5’-3’sugar-phosphate links that form a backbone.
Secondary structure of DNA
Flat base pairs lie perpendicular to the sugar-phosphate backbone.
B-DNA
A-DNA
Z-DNA
Tertiary structure of DNA
The structure of RNA
mRNA:carries the coding sequence
tRNA:provides the amino acid corresponding to each codon
rRNA:a major component of the ribosome that provides the environment for protein synthesis
The structure of protein
Primary structure
Amino acids are linked by peptide bonds.The linear number and order of the amino acids in peptide .
Secondary structure
Polypeptides can fold into a number of regular structures.The ordered array of amino acids in a protein confer regular conformational forms upon that protein,including α-helix,β-pleated sheets.
Tertiary structure
complete three dimensional structure of the polypeptide units of a given protein.The hydrophilic amino acids mostly on the surface and hydrophobic ones in the interior.
Quaternary structure
proteins was composed by more than one polypeptide subunit.
Domain
Semi-independent structural and functional units within a single polypeptide chain.Domains are often encoded by individual exons within a gene.
Motif
A pattern in a protein structure formed by the spatial arrangement of amino acids,are groupings of secondary structures or amino acid sequences often found in related members of protein families.It could be the sub-unit of domain.