What is melting temperature (Tm) of DNA? A DNA molecule with more number of GC base pairs than AT base pairs has higher Tm than the one with lesser number of GC base pairs than AT base pairs. Explain why?
The temperature at which two strands of DNA separates completely is known as its melting temperature. It is specific for each specific sequence.
A DNA molecule with more number of GC base pairs than AT base pair has higher melting temperature because each GC pair contains three hydrogen bonds, while each AT base pair contains two hydrogen bonds.Therefore, more number of hydrogen bonds are present in DNA molecule with more GC pairs than AT pair.
What are forces holds the two strands of DNA together in a double-helix structure? Draw structure to show the bonding between adenine and thymine, and between guanine and cytosine.
Explain the following:
Glucose responds Fehling solution and osazone, it does not react with Schiff’s base and sodium bisulphite.
Which vitamin is called ascorbic acid? What are its physiological functions? Which disease is caused by the deficiency of this vitamin?
Explain the following:
Glucosides react neither with Fehling solution nor with Tollen's reagent. They also do not allow mutarotation.
Explain the following:
Although fructose does not have an aldehydic group, it reacts with Fehling solution.
