Download Slide 1 DNA and RNA are two forms of nucleic acids

Slide 1
DNA and RNA are two forms of nucleic acids. This class of organic compound is composed of carbon,
hydrogen, oxygen, nitrogen and phosphorus. Within all life on earth, these nucleic acids serve primary
roles in the storage and use of hereditary information.
Slide 2
DNA and RNA have similar chemical structures and compositions. Both are composed of strands of
individual building blocks called nucleotides. Every nucleotide consists of three basic parts; a base
containing nitrogen and carbon, a sugar containing 5 carbons, also known as a pentose sugar, and a
phosphate group. The sugars and phosphates bond together covalently to form the so-called backbone
of a nucleic acid. DNA consists of two strands of these nucleotides, while RNA is a single strand of
nucleotides.
Slide 3
Taking a closer look at DNA, DNA stands for deoxyribonucleic acid. The sugar in DNA is called
deoxyribose. There are 4 different nitrogenous bases found in DNA. These are cytosine, thymine,
guanine, and adenine. Both cytosine and thymine possess single rings of carbon and nitrogen and are
referred to as pyrimidines. Adenine and guanine possess two rings of carbon and nitrogen, and are
called purines.
Within the DNA double helix hydrogen bonds form between the nitrogenous bases. Cytosine bonds or
pairs with guanine and adenine bonds with thymine. These consistent bonds are called base pairs.
The order of the bases, abbreviated A,T,C, and G is referred to as the DNA sequence. This sequence is a
simple code for determining the structure of polypeptides or proteins. Every code is called a gene. In
order for a cell to actually create a protein or polypeptide using these genes, the other nucleic acid, RNA
is used.
Slide 4
As mentioned previously, DNA stores all of the hereditary material for an organism, and this hereditary
material is the code of information needed to build proteins. However, the building of proteins can not
be accomplished without the other nucleic acid called ribonucleic acid or RNA. While DNA is found
primarily in the nucleus of a cell, RNA can be found in the nucleus as well as throughout the cell. There
are several different forms of RNA, but they all have the same basic characteristics. RNA, like DNA is
made out of strands of nucleotides. In an RNA nucleotide the sugar is ribose, and the phosphate group
is the same as in DNA. Most of the RNA nitrogenous bases are the same as in DNA, including cytosine,
guanine, and adenine. However in RNA, the pyrimidine Thymine is replaced by Uracil.
Unlike the double-stranded helix of DNA, RNA exists as a single stranded molecule. That single strand
can twist and fold and as a result form base pairs, between cytosine and guanine, and adenine and
uracil. The shape of the final molecule influences its function or role. One form of RNA called
messenger RNA (mRNA) is formed within the nucleus for the purpose of copying the DNA message and
transporting that message to the location of protein synthesis, which happens to be outside of the
nucleus. Ribosomal RNA (rRNA) along with proteins forms the structure of a ribosome; a cellular
structure used in the process of protein synthesis. Transfer RNA (tRNA) is also used in protein synthesis
where its primary purpose is to transport the building blocks of proteins, called amino acids to the
ribosomes for protein synthesis.