DNA consist of macromolecules which are; nitrogenous base, a phosphate sugar backbone and a pentose sugar. DNA has a double helical structure due to the coiling of two biopolymer strands. This double helix structure is made of nucleotides composed of either, thymine, guanine, cytosine or adenine, a monosaccharide(deoxyribose) and a phosphate group. Covalent bonds join the nucleotides together in a chain form. This is between the deoxyribose sugar of one nucleotide and the phosphate component of the other nucleotide, which brings about the alternating sugar phosphate backbone.All biological information is stored in DNA which makes every organism unique.
The rough endoplasmic reticulum is involved in synthesizing and packaging proteins for use. It has ribosomes attached to it which is what makes it rough. The smooth endoplasmic reticulum functions as storage for lipids and sterols. Only eukaryotic cells have an endoplasmic reticulum.
Figure.12: The complex structure of all the subunits of gamma-secretase . The Ramachandran plot analysis of the gamma protein structure is finished for the favoured region, allowed region and also the outlier regions. The tertiary structure of the gamma-secretase is being predicted with generally number of residues in the favoured region in Ramachandran plot. The residue in favoured region and also the allowed regions are found to be 91.40 % and 6.0 % of the total residues respectively. This show good interaction of subunit structures to form the complex structure of γ-secretase.
Initially, stretches of single stranded DNA (ssDNA) are resected at the stalled forks or DSB ends which are quickly bound by replication protein A (RPA). Rad51 replaces RPA and binds to these ssDNA with the aid of the Rad52 mediator function (21,22). Rad51 form a nucleoprotein filament, which can then engage in homology search by strand invasion forming a homologous DNA
DNA synthesis. When primers detect and limit the amplification DNA sequence on two sides, the thermostable DNA polymerase synthesizes a complementary fragment from the 3 'end of the primers from both DNA single chain fragments using the nucleotides added to the mixture. The procedure is carried out at 72 ° C, using a thermostable Taq polymerase. APPLICATIONS: The ability of the PCR to analyze a very small amount of DNA plays an important role in disease diagnostics. One of the important uses of PCR is the diagnosis of possible AIDS infection at a very early stage even before antibodies have developed .
Other genes with adjacent methylated CpG islands are transcriptionally silenced. The methyl groups in CpG islands occupy the major groove of DNA, and block the binding of transcription factors necessary to form transcription complexes. CpG islands are usually located upstream of promoter regions The bulk of methylated CpG dinucleotides are not adjacent to genes, and are found in repetitive DNA sequences located in heterochromatic regions of the genome, including the centromere. Methylation of these sequences contributes to silencing the transcription and replication of transposable elements such as LINE (long interspersed nuclear element) and SINE (short interspersed nuclear elements) sequences, which form a major part of the human genome. Heterochromatic methylation also maintains chromosome stability by preventing translocation and other chromosomal abnormalities.
1. Introduction: a. Hemoglobin structure: Hemoglobin is metalloprotein found in red blood cells having four polypeptide chains. Adult hemoglobin contains 2 alpha (141amino acid) and 2 beta chains (146 amino acid) which forms a tetramer called as globin and each chain is attached to iron containing prosthetic group heme (protoporphyrine IX). Ferrous ion of this heme is linked to globular protein by binding ‘N’ in the center of the protoporphyrin ring. There is a non-covalent interaction between four chains.
Eg. Ferritin. Nucleic Acids  Nucleic acids are known as genetic materials. They are macromolecules meaning that they are polymers of nucleotides (phosphate group, pentose sugar, and a nitrogenous base). Living matter is composed of nucleic acids in the form of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA).
The MG state is a compact denatured state with a significant native like secondary structure but a largely disordered tertiary structure. In addition, there are studies demonstrating that proteins can convert from unfolded to folded or molten-globule states upon addition of large amounts of crowding agents. For instance, unfolded cytochrome c at pH 2 can adopt a molten globule structure in the presence of crowding agents, unfolded RNase A at pH 3 adopts a folded-like structure upon addition of 350 mg/ml PEG 20,000 or Ficoll 70, and the reduced and carboxyamidated form of RNase T1 that is intrinsically unstructured at pH 7 was found to exhibit some catalytical activity upon the addition of 400 mg/ml dextran 70. In addition, protein binding to a membrane surface results in “partial denaturation” (i.e. being transformed into a non-native state).
Amino acids are the building blocks of proteins. All amino acids have the same basic structure but differ in their R-side chains. Each amino acid consists of an amino group (-NH3), a carboxyl group (-COOH) and a hydrogen atom (H). The amino and carboxyl groups are attached to a central alpha carbon together with a hydrogen atom and an R-side chain. There are currently known that over 170 amino acids occur in organisms but only 20 are commonly found in proteins.