Final answer:
The genetic code of an organism is determined by the sequence of nitrogen bases in the DNA strand, which are arranged into codons that direct the synthesis of proteins.
Step-by-step explanation:
The part of the DNA strand that creates an organism's genetic code is the sequence of nitrogen bases: adenine (A), cytosine (C), guanine (G), and thymine (T). This sequence of bases encodes the instructions for building an organism's proteins. Proteins are vital for cellular structure and function, and they are synthesized based on the genetic code carried by genes. A gene is a segment of DNA that carries the code for making a specific polypeptide chain.
During the process known as transcription, the DNA's code is copied into messenger RNA (mRNA), which is then used during translation to synthesize proteins. The mRNA consists of codons, sets of three bases, each coding for a single amino acid or a start or stop signal during protein synthesis. Thus, the genetic code is read from the DNA and transcribed into RNA before being translated into proteins. This process occurs in both prokaryotic and eukaryotic organisms and demonstrates the universality of the genetic code.