This is due to the similar electronic configuration (more importantly the number of valence electrons). Among the two groups given here, choice (b) Mg, Sr and Ba are alkaline earth elements (part of group IIA) in the periodic table. Other elements of this group are Be, Ca and Ra. All these elements form the alkaline earth metal group of the periodic table. All these elements have 2 valence electrons, which they can give up to attain a +2 charge as cations. They have certain common properties, including shiny and silver-white appearance.
The backbone of the DNA strand is made from alternating phosphate and sugar residues. The sugar in DNA is 2-deoxyribose, which is a pentose (five-carbon) sugar. The sugars are joined together by phosphate groups that form phosphodiester bonds between the third and fifth carbon atoms of adjacent sugar rings.he backbone of the DNA strand is made from alternating phosphate and sugar residues. The sugar in DNA is 2-deoxyribose, which is a pentose (five-carbon) sugar. The sugars are joined together by phosphate groups that form phosphodiester bonds between the third and fifth carbon atoms of adjacent sugar rings.
A DNA strand is simply a string of nucleotides joined together. I can show how this happens perfectly well by going back to a simpler diagram and not worrying about the structure of the bases. The phosphate group on one nucleotide links to the 3' carbon atom on the sugar of another one.In the process, a molecule of water is lost-another condensation reaction. . . . and you can continue to add more nucleotides in the same way to build up the DNA chain.xploring a DNA chain The sugars in the backbone The backbone of DNA is based on a repeated pattern of a sugar group and a phosphate group. The full name of DNA, deoxyribonucleic acid, gives you the name of the sugar present-deoxyribose. Deoxyribose is a modified form of another sugar called ribose.