Which conformation of DNA – (i) totally double helix, (ii) minimally unwound or (iii) largely unwound – would have the highest relative absorbance at 260 nm. Would a molecule of DNA having a higher content of guanine and cytosine than of adenine and thymine have a higher or lower melting temperature (Tm) than one with the reverse composition?
DNA and RNA
Deoxyribonucleic acid (DNA) is usually called the blueprint of life. Deoxyribose is a monosaccharide that has a key function in the synthesis of deoxyribonucleic acid. One less oxygen-containing hydroxyl group occurs in deoxyribose sugar. Nucleic acid, deoxyribonucleic acid, is one of the natural components. Deoxyribonucleic acid is a double-stranded molecule. Watson and Crick postulated the double-stranded model of the helix. A deoxyribonucleic acid is a molecular group that carries and transmits genetic information from parents to offspring. All eukaryotic and prokaryotic cells are involved.
DNA as the Genetic Material
DNA, or deoxyribonucleic acid, is a long polymeric nucleic acid molecule discovered in the late 1930s. It is a polymer; a long chain-like molecule made up of several monomers connected in a sequence. It possesses certain characteristics that qualify it as a genetic component. Certain organisms have different types of nucleic acids as their genetic material - DNA or RNA.
Genetics
The significant branch in science which involves the study of genes, gene variations, and the organism's heredity is known as genetics. It is also used to study the involvement of a gene or set of genes in the health of an individual and how it prevents several diseases in a human being. Thus, genetics also creates an understanding of various medical conditions.
DNA Replication
The mechanism by which deoxyribonucleic acid (DNA) is capable of producing an exact copy of its own is defined as DNA replication. The DNA molecules utilize a semiconservative method for replication.
Just as a high temperature can denature protein, nucleic acids such as DNA and RNA can too be denatured or 'melted' by increasing the temperature. DNA of each species of organism has a characteristic denaturation temperature called Melting temperature or Tm.
When only the hydrogen bond between the nitrogenous bases of the two strands is broken (no covalent bond is broken) by increasing the temperature, it can result in the unwinding or 'melting' of the double helix into two separate strands. The unwinding can be partial or complete unwinding.
When the temperature is returned to a normal range the two separated strands come together and re-wind to form the double helix. This is known as annealing.
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