Question

What is our current state of knowledge on DNA.

What Links genetic characteristics to DNA structure.

What are the steps in the process of protein synthesis.

How can it be that DNA through the process of protein synthesis is responsible for the ultimate expression of the characteristics in the organism.

How can interference in protein synthesis can result in disruption of cellular and bodily processes?

Answer 1

1. DNA is simply a small biomolecule which contains hereditary information. The genetic information which needs to be passed from parents to progeny is contained by these molecules. DNA is composed of 2 antiparallel coiled chains, DNA is a double helical structure. These chains are called polynucleotides and their complex is called Nucleotide. A nucleotide is made up of a sugar, (which in DNA is De-oxyribose), a phosphate group and a nitrogenous base (which are 4-  Adenine, Guanine, Thymine and Cytosine). This is the basic of a DNA molecule.

2. DNA is the molecule which contains all the genetic material. DNA is in condensed form in a cell which are called chromosomes. These chromosome carry genetic information in the form of gene. The genetic characteristics reach from parents to progeny after mitosis, in which DNA sequence is copied in the daughter cells. In DNA a specific portion encodes for a specific trait or character which is called a gene. The genetic information inherited from parents to progeny in form of Homologous chromosomes.

3. DNA in cell's nucleus go through a mechanism of 3 steps which are Replication, Transcription and Translation. DNA replicates itself and then makes a transcript or mRNA which further helps in protein synthesis. Translation is process of formation of peptide bonds between carboxyl group of one amino acid and amino group of another. Translation occurs in the ribosome. In the process mRNA, tRNA and rRNA take part.

• mRNA or messenger RNA contains all the genetic information which is in the form of 3 base codons, each of these codon specifies a particular amino acid.
• tRNA or transfer RNA are the interface between the nucleic acid language and protein language. Each amino acid has it's own tRNA. tRNA binds with it's specific amino acid and carries it to chain of polypeptide.
• rRNA or ribosomal RNA along with some ribosomal proteins are in Ribosomes, which are the factory of protein synthesis. Ribosomes has small and large sub-units. These proteins helps the upcoming amino acids with charged tRNA to bind with the peptide chain. They catalyze the assembly of amino acids into proteins chains.

Translation of mRNA molecule occur in 3 steps- Initiation, Elongation and Termination.

1. In Initiation- the mRNA molecule binds to the small sub-unit of ribosome where charged tRNA binds the amino acids to the start codon- AUG, of mRNA sequence. Along with large ribosomal subunit the initiation complex is made.
2. In Elongation- the ribosome keep on translating the amino acid sequence. And these amino acid sequence binds to each other and elongate the polypeptide chain by joining each other with peptide bonds.
3. Termination- When all the codons are translated there come to end of elongation. The mRNA shows the stop codon (UAA, UAG, UGA) , no tRNA can recognize these codons so ribosome automatically stop the translation process. By the end of translation, a new protein is made by the translated amino acid sequence peptide chains.