Transcription of two genes. (a) RNA polymerase moves from the 3â² end of the template strand, creating an RNA strand that grows in a 5â² â 3â² direction (because it must be antiparallel to the template strand).
The atoms in sugar do not form ions; instead, they share their electrons. The type of bond that forms from the sharing of electrons between the atoms of the table sugar is a covalent bond. Table sugar has a much more complex chemical structure than salt.
Each strand of the double helix is held together by covalent bonds between deoxyribose sugar and phosphate groups (on the 3' and 5' carbons) (making up the backbone). The bases - purines or pyrimidines - (adenine, guanine, cytosine and thymine) are also bonded onto the deoxyribose sugar (on 1' carbon) covalently.