School of Life Sciences | Ask A Biologist

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Turning DNA into Proteins

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  • Gene: a region of DNA where a specific set of instructions for one trait is kept. We get some of our genes from our mother and some from our father... more
  • Protein: a type of molecule found in the cells of living things, made up of special building blocks called amino acids.
  • RNA: an acid found in all living things that carries messages from DNA to the rest of the cell to be made into protein.
  • Ribosome: a cellular organelle that is responsible for making proteins.

Transcription and translationIn each cell type different genes are active that produce only those proteins that are needed in the specific cell. But how exactly is it possible for the cell to produce a protein out of the recipe on the DNA? Reading a recipe is not enough; protein production involves further steps: transcription and translation.

Transcription

For creating proteins there is a special organelle in the cell called the ribosome. The ribosome is found in the cytoplasm of the cell. However, the genetic code on the DNA is contained in the nucleus, which is in a different part of the cell. This makes for a bit of a problem, as the ribosome needs the genetic code to make proteins. Taking the DNA into the cytoplasm wouldn't be possible - remember that this is a huge molecule.

To overcome this problem, the cell has found another simple solution: It creates a small copy, or a 'transcript,' of the specific gene, through the copy process of transcription. This copy is a small RNA molecule, called messengerRNA. RNAs are very close relatives of DNA. They consist of nearly the same material. But, whereas DNA is double stranded, RNA is built by only one strand. RNAs are small enough to exit the nucleus through a small pore in the membrane.

Translation

TranslationThe actual step of protein production is called translation. This is when the code on the messengerRNA is translated into the small building blocks of proteins – the amino acids. Once transported into the cytoplasm, the instructions on the messengerRNA are read by the ribosome. According to the instructions the ribosome puts together the necessary amino acids in a specific order to build the respective proteins. Each protein is manufactured as long “pearls on strings” with amino acids being the pearls.

DNA double helix

To make proteins, part of one side of two-stranded DNA is copied to make single-stranded RNA. This strand can then be used in the ribosomes to make proteins.

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DNA double helix

To make proteins, part of one side of two-stranded DNA is copied to make single-stranded RNA. This strand can then be used in the ribosomes to make proteins.

Share to Google Classroom

Be part of Ask A Biologist

by volunteering, or simply sending us feedback on the site. Scientists, teachers, writers, illustrators, and translators are all important to the program. If you are interested in helping with the website we have a Volunteer page to get the process started.