RNA is also a nucleic acid but is different from the DNA molecule. The sugar is a ribose sugar and not a deoxyribose sugar. The thymine nucleotide is not seen in the RNA molecule. Instead, there is guanine, which has a base pair with adenine in doublestranded RNA. Most RNA, however, is single stranded and does not have a base pair situation happening with it.
WATER AND BIOLOGY Water is extremely important to life because it has a number of features that make it an excellent medium in which to have the biochemical reactions necessary for life occur. It is also very abundant in the earth; in humans, it involves 70 percent of the body. Perhaps there are life forms on other planets that do not contain water as part of their structure; however, life as we know it on earth is entirely dependent on it. What features make water so good when it comes to life? As mentioned, water is a polar substance, which means that it is a molecule with a positive end electrically and a negative end electrically. This causes it to connect to or bind easily to other polar 19
