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How Does Our DNA Make Our Traits?

DNA is stored in the nucleus of cells in both heterotrophs (animal cells) and autotrophs (plant cells). The coded information in the genes is used to synthesize (make) many types of molecules. Most of these molecules are proteins. Protein molecules are long chains formed from 20 kinds of amino acids arranged in a specific sequence. Amino acids are the building blocks of proteins. Ribosomes help construct these proteins by bringing the amino acids together and connecting them. The amino acids are selected because of the directions stored in the cell’s DNA code.

The sequence of amino acids in a protein influences the shape of the protein. The long amino acid chain folds and bends. The final folded shape of the protein allows it to carry out its function (job) in the cell. For example, many proteins made by a cell become enzymes that speed up chemical reactions.

Because offspring inherit genetic information from their parents, their cells make many of the same proteins. This is what causes the resemblance between some children and their parents. Making many of the same proteins causes both parents and offspring to form similar structures that give them similar features. The entire process in which proteins are made is called gene expression, or protein synthesis.

What are the steps to making our traits?

The instructions for making a protein are coded in the sequence of nucleotides (bases) in the gene. The instructions for making a protein are transferred from a gene in the DNA to an RNA molecule in a process called transcription. “Scribe” in transcription means “write”. The DNA is re-written as RNA.

Transcription of the DNA occurs in the nucleus.  There, the DNA code of a particular gene is “read” by a special molecule and used to produce a “messenger” molecule called RNA. First, the DNA unwinds so it is in two separate strands. Then, RNA is made using one strand which is called the coding strand. The other strand that is not used is called the complementary strand. 

The RNA leaves the nucleus. Other molecules then read the instructions on the RNA messenger molecule and put together the amino acids that make up the protein. Every three bases or a codon of the RNA strand is read to make an amino acid. This process is called translation. The RNA code gets “translated” into the language of amino acids. Translation happens in the cell’s cytoplasm with the help of the ribosomes. The ribosomes read the RNA, creating the amino acids and putting them together into a protein.