DNA and RNA

DNA to protein translation process   - This one-way flow of information from DNA to protein is called the central dogma of molecular biology. Information stored in DNA is copied to RNA (transcription), which is used to assemble proteins (translation). Each DNA strand is composed of sub-units called nucleotides or, “bases” for short.  There are four types of nucleotides – adenine, A; thymine, T; guanine, G and cytosine, C. An A always pairs with T, and G with C. Thus the two strands of DNA are complementary to each other. Nucleotides are arranged in a specific order on DNA – this is called the sequence of DNA.  This sequence is further sectioned into genes – a short segment of DNA that is made into one polypeptide (protein) chain. Cells convert DNA to protein in a two-step process. Transcription: DNA to RNA Transcription occurs in the nucleus. Transcription in the process by which RNA is assembled from a DNA template. To transcribe a gene, the DNA is first unwound u

Trisomy 13 or Patau Syndrome  is the most severe viable trisomy caused by an additional copy of chromosome 13 that usually causes a host of developmental problems and physical deformities in a newborn. Patau syndrome is generally recognized at birth by the presence of structural birth defects and poor neurologic performance. Additional structural anomalies are common, particularly facial anomalies (midline clefts, hypotelorism, microphthalmia, and anophthalmia) arising from structural anomalies of the brain, frequently microcephaly and holoprosencephaly. Other associated anomalies include cardiac, renal, and intestinal (diaphragmatic hernia) anomalies. Characteristic features include low set ears, post-axial polydactyly, flexion contractures, rocker bottom feet, scalp defects, and haemangiomas. What is the cause of Patau Syndrome ? The exact incidence of Patau syndrome is not known, although it appears to affect females more than males, most likely because male fetuses do not

What is Complementary Bases in DNA ? -  DNA is made up of two chains of molecules called nucleotides; thing of it as two bead necklaces, each bead being a nucleotide. Complementary base pairing ensures that the daughter DNA molecule obtained during replication is exactly like that of the original strand. DNA replication is semiconservative and at such, complementary base pairing ensure that if adeinine is found on one strand, thymine is found on the other complementary base pairing also help to hold the double helix together by the formation of hydrogen bond. The two chains (or strands) are joined by each bead (nucleotide) so that it looks like a ladder (a helix). The bonds between the nucleotides on the two strands are hydrogen bonds, and these are formed between a special part of the nucleotide called a base (or nitrogenous base). DNA double helix is formed Video Scheme of unusual pairing of complementary bases in DNA : Besides the normal pairing of Dna bases, for

Synthesis Direction of DNA -  When DNA is synthesized, the free 3´ hydroxyl (OH) group from the growing strand of DNA attacks the phosphate on the next base to be added. When a cell divides, it passes on genetic information by producing copies of its DNA. Chemists have also learned to copy DNA. In the journal Angewandte Chemie, a German team has now introduced a new copying technique that uses a single strand of DNA as the “master copy”, like a cell, but does not require enzymes. Pyrophosphate is released and the new base forms a phosphodiester bond with the growing strand of DNA. The free 3´ hydroxyl group is then freed to attack the next base to be added. Within a cell, the DNA double strand is separated in segments during the copying process. One of the single strands serves as the “master copy” or template. Polymerase enzymes snap together the corresponding nucleotides stepwise to form the new complementary strand, beginning with a “starting segment” known as a primer. The

What is Three Parts of Nucleotide ? Nucleotides are biological molecules that form the building blocks of nucleic acids (DNA and RNA) and serve to carry packets of energy within the cell (ATP). In the form of the nucleoside triphosphates (ATP, GTP, CTP and UTP), nucleotides play central roles in metabolism.  In addition, nucleotides participate in cell signaling (cGMP and cAMP), and are incorporated into important cofactors of enzymatic reactions (e.g. coenzyme A, FAD, FMN, NAD, and NADP+). A nucleotide is composed of a nucleobase (nitrogenous base), a five-carbon sugar (either ribose or 2-deoxyribose), and one or more phosphate groups. Three parts of nucleotide image  That are three parts of nucleotide, Nucleotides can be synthesized by a variety of means both in vitro and in vivo. There a 4 different nucleotides ATP,GTP (purines) TTP,CTP (pyrimidines) which differ in the chemical structure of the base. They are generally referred by a single letter A, G, T,C. UTP

Blue-eyed parents can have brown-eyed kids and other eye-oddities ? Eye color is much more complicated than is usually taught in high school (or presented in The Tech’s eye color calculator).  There we learn that two genes influence eye color. One gene comes in two versions, brown (B) and blue (b).  The other gene comes in green (G) and blue (b).  All eye color and inheritance was thought to be explained by this simple model.  Except of course for the fact that it is obviously incomplete. New research shows that the first gene is actually two separate genes, OCA2 and HERC2.  In other words, there are two ways to end up with blue eyes. Normally this wouldn’t be enough to explain how blue eyed parents can have a brown eyed child.  Because of how eye color works (see below), if one gene can cause brown eyes, it would dominate over another that causes blue.  In fact, that is what happens with green eyes in the older model.  The brown gene dominates over the green one resulting in