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1. #Lumen learning boundless anatomy and physiology full#
2. #Lumen learning boundless anatomy and physiology code#

The triplets within the gene on this section of the DNA molecule are used as the template to transcribe the complementary strand of RNA (Figure 2).

Transcription begins in a fashion somewhat like DNA replication, in that a region of DNA unwinds and the two strands separate, however, only that small portion of the DNA will be split apart. This process is called transcription because the mRNA is like a transcript, or copy, of the gene’s DNA code. Gene expression begins with the process called transcription, which is the synthesis of a strand of mRNA that is complementary to the gene of interest. This means that adenine will always pair up with uracil during the protein synthesis process. Finally, instead of the base thymine, RNA contains the base uracil. Second, the ribose sugar in RNA contains an additional oxygen atom compared with DNA. For one thing, unlike DNA, most types of RNA, including mRNA, are single-stranded and contain no complementary strand. The structure of RNA is similar to DNA with a few small exceptions. There are several different types of RNA, each having different functions in the cell.

#Lumen learning boundless anatomy and physiology code#

This intermediate messenger is messenger RNA (mRNA), a single-stranded nucleic acid that carries a copy of the genetic code for a single gene out of the nucleus and into the cytoplasm where it is used to produce proteins. From DNA to RNA: TranscriptionĭNA is housed within the nucleus, and protein synthesis takes place in the cytoplasm, thus there must be some sort of intermediate messenger that leaves the nucleus and manages protein synthesis. The nucleotide sequence of a gene is ultimately translated into an amino acid sequence of the gene’s corresponding protein.

The mechanism by which cells turn the DNA code into a protein product is a two-step process, with an RNA molecule as the intermediate.įigure 1. The Genetic Code. DNA holds all of the genetic information necessary to build a cell’s proteins. Therefore, a gene, which is composed of multiple triplets in a unique sequence, provides the code to build an entire protein, with multiple amino acids in the proper sequence (Figure 1). Similar to the way in which the three-letter code d-o-g signals the image of a dog, the three-letter DNA base code signals the use of a particular amino acid.įor example, the DNA triplet CAC (cytosine, adenine, and cytosine) specifies the amino acid valine. A triplet is a section of three DNA bases in a row that codes for a specific amino acid. The sequence of bases in a gene (that is, its sequence of A, T, C, G nucleotides) translates to an amino acid sequence. Recall that proteins are polymers, or chains, of many amino acid building blocks. The interpretation of genes works in the following way. Gene expression, which transforms the information coded in a gene to a final gene product, ultimately dictates the structure and function of a cell by determining which proteins are made. Each particular gene provides the code necessary to construct a particular protein. A gene is a functional segment of DNA that provides the genetic information necessary to build a protein.

#Lumen learning boundless anatomy and physiology full#

Just as the cell’s genome describes its full complement of DNA, a cell’s proteome is its full complement of proteins. Whatever the cellular process may be, it is almost sure to involve proteins.

Some of these critical biochemical reactions include building larger molecules from smaller components (such as occurs during DNA replication or synthesis of microtubules) and breaking down larger molecules into smaller components (such as when harvesting chemical energy from nutrient molecules). One of the most important classes of proteins is enzymes, which help speed up necessary biochemical reactions that take place inside the cell. Most structural components of the cell are made up, at least in part, by proteins and virtually all the functions that a cell carries out are completed with the help of proteins. This refers to the fact that DNA contains the information necessary for the cell to build one very important type of molecule: the protein. It was mentioned earlier that DNA provides a “blueprint” for the cell structure and physiology.