CHE 161 - Nucleic Acids

Describe and draw the structure of nucleic acids.

Nucleic acids are polymers composed of nucleotides, which are made of a phosphate group bonded to a sugar, which is bonded to a nitrogenous base.

Compare the sugars used for DNA and RNA

DNA uses deoxyribose as the sugar molecule, while RNA uses ribose. You can tell the difference by observing whether there are two OH groups on the bottom of the sugar or one. (DNA = deoxyribose = no OH on C2).

What are the two families of nitrogenous bases?

The two families of nitrogenous bases are purines and pyrimidines. Pyrimidines are made of one six sided ring, while purines have two 5-sided rings.

What two nitrogenous bases are only found in either RNA or DNA?

Uracil is only found in RNA, while thymine is only found in DNA.

Describe the structure of DNA.

DNA is found as two strands held together by hydrogen bonding. It is double stranded so that there is a backup copy of genetics, and it’s structure protects the nitrogenous bases in the middle of the helix.

Describe the structure of RNA.

RNA is single stranded.