P.Oudet named NucleosomeR. Korenberg-gave the Nucleosome Model Nucleosome – It is a circular structure of 10 nm diameter which is made up of 146 bp. In this, DNA is wrapped on Octamer unit of 8 Histone by taking one complete round and another 3/4. Two octaves of H2A, H2B, H3 and H4 histone are present …
When DNA is exposed to external chemicals or radiation, its chemical physical structure changes. Due to which the replication or transcription is blocked which is fatal. And it generates mutation by direct or indirect mutagenesis. This chemical instability of DNA generates spontaneous lesions. DNA Lesions The change in the normal chemical and physical structure of …
DNA Replication is Semi-Conservative: Watson and Crick model suggested that DNA replication is semi-conservative. It implies that half of the DNA is conserved. Only one new strand is synthesized, the other strand is the original DNA strand (template) that is retained. Each parental DNA strand serves as a template for one new complementary strand. The …
Greek Chroma = colour. Name given by Flemming (Flemming, 1879) In the nucleus, DNA combines with a specific type of protein to form a complex structure called Chromatin. Chromatin contains DNA/RNA/Histone Protein, Alkaline Protein and Non Histone Protein (Acidic Protein). It is a threadlike structure. Which is called Chromonemata, which intertwine together to form …
Genetic RNA: It is found in some viruses called riboviruses. Genetic RNA may be single stranded (e.g., Tobacco Mosaic Virus or TMV) or double stranded (e.g., Rheovirus). Genetic RNA acts as a hereditary material. It may, however, not replicate directly, but form DNA in the host cell to produce RNA of its own types. Non …
Wilkinson at all define the double helical structure of DNA and their measuring by the X-rya crystallography. This type of DNA known as B-DNA and it is found in many species. Other than this A.C,D and Z DNA also found in organism. According to the helical structure and morphology DNA are following type. Circular DNA …
Watson and Crick model of DNA This model of DNA proposed by Watson and Crick and supported by Wilkins et. al., by x-ray crystallography of DNA. According to this model. DNA consists of two, polynucleotide chains which are twisted around each other and forming a right-handed double helix around the same central axis. These chains …
Structure of DNA DNA is formed by the joining of many nucleotides. These nucleotides are called monomers. Phosphate and sugar in DNA are linked together by ester bonds. It is arranged in an alternate order. Nitrogen bases are linked to each other by H-bonds and to sugars by glycosidic bonds. Nitrogen bases are arranged on …
Structure of DNA : Biochemical composition of DNA Discover – Miescher- Pus-cell -Name Nuclein Altman -Nucleic Acid Each nucleotide unit consists of three types of compounds which are as follows : (1) A pentose sugar -the 5 carbon deoxyribose sugar (2) 2. Phosphoric Acid (H₃PO₄) (3) Nitrogenous base-a heterocyclic ring containing nitrogen 1. Pentose sugar …
Chemical Nature of DNA/ Biochemical organization of DNA Read More »
Biological Role of DNA 1.synthesis of Protein – Transcription – The process in which the information present on a DNA molecule is written by a base sequence to its complementary sequence to mRNA. Translation – In this, the information located on the mRNA is translated as a chain of amino acids to form a protein. …