DNA Presence and Structure:
DNA is found in almost all living cells whereas its location within a cell varies based on the nucleus. All organisms are composed of cells that either contain nuclei or not. Cells those are containing nuclei are classified as eukaryotic and those are not known as prokaryotic. In eukaryotic cells, DNA is housed within the nucleus but in the case of prokaryotic cells, DNA is located directly within the cellular cytoplasm because the nucleus is absent.
DNA carries information about your physical characteristics as per your ancestors like height, weight, body structure, etc. These physical properties are mainly determined by proteins. And DNA contains the instruction set for making proteins. In DNA, each protein is encoded by gene. Gene is a specific sequence of DNA nucleotides that specify how a single protein is to be made. When nucleotides join together in a series, they form a structure known as a polynucleotide. DNA is often found as stranded polynucleotide either single-stranded or double-stranded.
The main components in DNA are given below:
- A phosphate molecule
- A sugar molecule (Deoxyribose, containing five carbon atoms)
- A nitrogen-containing region
The nitrogen-containing regions known as bases are adenine (A), cytosine (C), guanine (G), and thymine (T). Order these four bases forms the instruction sets for making proteins or genetic codes.
The bases of the two strands of DNA are joined together to create a ladder-like structure. In this ladder, Adenine (A) creates a bond with Thymine (T) and Guanine (G) creates a bond with Cytosine (C). This bond is a hydrogen bond.