The sympathetic nervous systemâs fight-or-flight response is your built-in mechanism for safely escaping a life-threatening emergency, such as a lion lurking behind a bush.
The basic building block of DNA is called a NUCLEOTIDE. A nucleotide is made up of one sugar molecule, one phosphate molecule and one of the four bases. Here is the structural formula for the four nucleotides of DNA. Note that the purine bases (adenine and guanine) have a double ring structure while the pyrimidine bases (thymine and cytosine) have only a single ring.
Merge this question into. Split and merge into it. Answer by 1Jazz. Confidence votes 9.4K. The sugar-phosphate backbone of DNA is held together by covalent bonds. The strands of DNA are joined by hydrogen bonds (H-bonds) between the nitrogenous bases on either side. Adenine is joined to Thymine by 2 H-bonds.erge this question into. Split and merge into it. Answer by 1Jazz. Confidence votes 9.4K. The sugar-phosphate backbone of DNA is held together by covalent bonds. The strands of DNA are joined by hydrogen bonds (H-bonds) between the nitrogenous bases on either side. Adenine is joined to Thymine by 2 H-bonds.