structure of genes

• Walter Sutton and Theodore Boveri discovered that the basic hereditary factors involved in Mendelian genetics are within the chromosomes.
• The Chromosomal Theory of Inheritance or the Boveri-Sutton Chromosome Theory states that chromosomes are nuclear structures that consist of interlinking genetic material called deoxyribonucleic acid (DNA).
• Chromatin is the long fibrous strands 
• The chromatin folds into a compact structure with the help of histones.
• Histones are bead-like masses of proteins that provide the energy needed to compress DNA materials.
• The beads of histones are nested within nucleosomes, which store and hold the DNA.
• Nucleosomes are the basic unit of chromosomes. 
• Deoxyribonucleic acid or DNA is a nucleic acid that contains the genetic information of an organism.
• DNA dictates innate characteristics, influences behavior, and carries the identity of an organism.
• DNA functions like a blueprint that bears the instructions for the mechanisms of the development of an individual.
• DNA is a nucleic acid, a complex macromolecule consisting of chemical substances.
• Ribonucleic acid or RNA is a substance involved in the genetic translation of DNA into protein.
• The double helix is the twisted ladder-like structure of DNA.
• The double helix consists of nucleotides, molecules made from the combinations of three different molecules, including a phosphate group, a 5-carbon sugar group called deoxyribose, and nitrogenous base pairs.
• A sugar-phosphate backbone is bonded covalently, forming a continuous chemical chain.
• Nitrogenous bases are aromatic chemical substances categorized into two types: pyrimidines, and purines.
• Pyrimidines have a single chain in their chemical structure. 
• Pyrimidines consist of Thymine (T) and Cytosine (C).
• Purines are composed of two-ring chains.
• Purines consist of Adenine (A) and Guanine (G).
• Erwin Chargaff discovered that this particular arrangement appears not only in the base composition of human DNA but also in the base structure of other organisms. 
• Guanine-cytosine (G = C)
• Cytosine-guanine (C = G)
• Adenine-thymine (A = T)
• thymine-adenine (T = A)
• Genes are materials in DNA molecules that are responsible for the transmission of characteristics from parents to offspring.
• Johann Friedrich Miescher discovered DNA through an experiment on white blood cells, he referred to it as “nuclein” from which nucleic acid was derived but he dismissed the idea that it carried genes.
• Oswald Avery confirmed that DNA indeed contained genetic information. 
• Oswald Avery and other colleagues found out that the DNA of R-type bacteria can make them transform into S-type bacteria.
• Martha Chase and Alfred Hershey performed their experiment on bacteriophages, viruses that can infect bacteria.
• Francis Crick and James Watson in Cambridge published their discovery of the double helix structure in the issue of Nature, a British scientific interview.
• Rosalind Franklin applied the process of X-ray crystallography, in which an X-ray beam that penetrates a crystal produces a diffracted image used in identifying the three-dimensional structure of an object.
• Exposure 51, a diffracted image of a DNA molecule, shows the DNA structure.
• Maurice Wilkins, who provided Rosalind with the DNA molecule, took samples of the DNA X-ray photographs and showed them to Watson and Crick.
• Ribonucleic acid is a molecular chain composed of nucleotides with only one strand and four nitrogen bases.
• Uracine (U) is a pyrimidine that replaces the thymine base in DNA.