DNA and its close relative RNA are perhaps the most important molecules in biology. They contains the instructions that make every single living organism on the planet. DNA stands for deoxyribonucleic acid and RNA for ribonucleic acid. They are polymers (long chain molecules) made from nucleotides. Nucleotides Nucleotides have three parts to them: • a phosphate group, which is negatively charged.
Enzymes called topoisomerases produce breaks in the DNA molecules and then reconnect the strands, relieving strain and effectively preventing tangling and knotting during replication. DNA polymerase adds new nucleotides to a growing strand of DNA. Because DNA polymerase must adhere to an existing template, an RNA primer is first created at the site of replication. The RNA primer is synthesized by primase, an enzyme that is able to start a new strand of RNA opposite a DNA strand. After a few nucleotides have been added, the primase is displaced by DNA polymerase, which can then add subunits to the 3’ end of the short RNA primer.
Basically, DNA controls protein synthesis. The complex and precise process of protein synthesis begins within a gene, which is a distinct portion of a cell's DNA. DNA is a nucleic acid which is made up of repeating monomers, called nucleotides, and in the case of DNA, these individual monomers consist of a pentose sugar, a phosphoric acid and four bases known as adenine, guanine, cytosine and thymine. DNA is a double stranded polymer, which has a twisted ladder like
The nuclear envelope is marked with tiny holes called the complex nuclear pores; these keep the moving in and out of things like RNA and proteins between the cytoplasm and the nucleus running smoothly. The nuclear is a complex structure. The nucleus is surrounded by two layers of membranes, the inner and the outer layer. The outer membrane is continued from the endoplasmic reticulum. The outer layer acts much like the endoplasmic reticulum; it also has ribosomes attached to it.
During transcription, RNA polymerase makes a copy of a gene from the DNA to mRNA as needed. This process is similar in eukaryotes and prokaryotes. One notable difference, however, is that prokaryotic RNA polymerase associates with mRNA-processing enzymes during transcription so that processing can proceed quickly after the start of transcription. The short-lived, unprocessed or partially processed, product is termed pre-mRNA; once completely processed, it is termed mature mRNA. [edit] Eukaryotic pre-mRNA processingMain article: Post-transcriptional modification Processing of mRNA differs greatly among eukaryotes, bacteria, and archea.
The DNA in a eukaryotic cell is linear and is complexed with proteins called histones, these histones are simple alkaline proteins usually occurring in the cell nuclei and when combined with DNA they form nucleoproteins (Encyclopaedia Online Britannica). The DNA in prokaryotic cells is circular and simpler because the cell requires fewer genes to operate (cod.edu). Both cells contain organelles; organelles are any of the specialised structures within the cell that perform a specific function (Encyclopaedia Online Britannica). Ribosomes are found in the cytoplasm of both the cells, they are small structures built of two subunits and are constructed of protein and nucleic acid RNA. The main function of ribosomes is used as the site of protein synthesis this uses mRNA to produce proteins (C J Clegg 2008), however in eukaryotic cells the ribosome is more complex and contains five kinds of RNA and about eighty kinds of proteins but in a prokaryotic cell ribosomes are only made up of three kinds of RNA and about fifty kinds of proteins (cod.edu).
These charged molecules combine with oxygen and produce ATP molecules. This process is known as oxidative phosphorylation. Ribosomes: the ribosomes are the cellular component that make proteins from all amino acids. Ribosomes are made from complexes of RNAs and proteins.They assemble amino acids to form specific proteins, proteins are essential to carry out cellular activities. Rough endoplasmic reticulum: The surface of the rough endoplasmic reticulum is studded with the protein manufacturing ribosome, which gives it a rough appearance.The rough
The gene is often cut with staggered ends, called “Sticky Ends” which only allow specific and complementary gene sequences bond by base pairing. Due to these “Sticky Ends”, the scientists can exercise a degree of control over where the genes bond. -The next step in the process is to amplify the gene of interest using Polymer Chain Reaction or PCR. PCR serves to replicate specific gene sequences, creating many copies for the scientists to work with. -After the gene is amplified a suitable vector is selected for use.
This is the restriction enzyme and acts as “molecular scissors” cuts the two DNA chains at a specific area in the genome so that sections of DNA can be supplemented or detached. A piece of RNA known as guide RNA is the second key molecule. This consists of pre-designed RNA quite small in length sequence, consisting of about 20 bases, positioned within a longer RNA scaffold. The scaffold binds to DNA and the pre-designed sequence ‘guides’ Cas9 to the right part of the genome. ensuring that the Cas9 enzyme intersects at the right point in the genome.
The nucleic acid, DNA has an individual structure that act as an information storage molecule that provides instuction for assembling proteins. DNA’s primary structure involves nucleotide sequences that are monomer repeats which form polynucleotide chains[1]. The Primary structure of DNA begins with one of the two different 5 -carbon sugar components either known as 2-deoxyribose. The particular sugar can then either be linked to a hetrocyclic base by an N – Glycosidic bond[2]. The hetrocyclic bases are derived from two different structures which inculde Purine and Pyrimidine.