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  • Writer's pictureKaylyn Kim

How Are Proteins Made?

Written in March 2024 by Kaylyn Kim.

This easy-to-understand study guide strives to give a brief overview of how proteins are produced.


  1. mRNA (messenger RNA) is produced.

  2. The mRNA strand leaves the nucleus and heads for the ribosome/cytoplasm area.

  3. The tRNA strands (connected to amino acids) match with the mRNA strand.

  4. A long amino-acid chain is produced.

  5. Proteins can be formed with these amino-acid chains (AKA polypeptides).


  • Enzyme: a kind of protein that expedites chemical processes

    • Most enzymes end with the phrase "ase"

    • Example) RNA polymerase, DNA polymerase

  • DNA: deoxyribonucleic acid

    • The genetic information that most of our cells contain in the nucleus

    • Double-helix structure

  • Gene: segments of the DNA that produce a specific protein and, in turn, determine a specific trait

    • Allele: different kinds of genes

    • Example) One gene can code for hair color (broader term), but one allele would code for brown hair (more specific).

  • RNA: ribonucleic acid

    • Typically single-stranded

    • Different kinds) mRNA, tRNA, etc.

  • Protein synthesis: the process in which proteins are produced

  • Central Dogma: a term referring to how information goes from transcription (DNA --> RNA) to translation (RNA --> Amino Acids)

  • Protein: molecules that help organisms survive

  • Amino Acids: the material that the protein is made up of

    • There are 9 essential amino acids that humans need to survive.

  • Promoter: the marker that indicates where the RNA polymerase should attach to the DNA strand

  • Terminator: the marker that indicates where the RNA polymerase should detach from the DNA strand

  • Codons: a system for counting the nucleotide sequences in groups of 3 (triplets)

  • Nucleotide: the material in which nucleic strands are made up of (both DNA and RNA have)

    • DNA: Contains 1 nitrogenous base, 1 deoxyribose sugar, and 1 phosphate

    • RNA: same as DNA, except that it contains a ribose sugar, instead of a deoxyribose one

  • Ribosome: an organelle where protein synthesis takes place

    • Made up of rRNA (ribosomal RNA)

    • Has three sites for the tRNAs to briefly stay and pass on the amino acids

      • Sites A, P, E --> The tRNAs rotate their locations in that respective order

FIRST STEP: Transcription


  • Transcript often refers to the written documents of a video, so you can remember transcription as changing one form of something into another form.

  • In this case, DNA turns into mRNA.

  • Location: nucleus

  1. DNA is unzipped by the RNA polymerase at the promoter.

  2. The RNA polymerase "reads" the DNA's bases and creates complementary pairs.

    • Typically, adenine goes with thymine, but this time, thymine is replaced with a base pair called uracil.

    • Guanine goes with cytosine (and vice versa)

  3. This forms an mRNA (messenger RNA) strand.

    • It is then edited and sent out of the nucleus and into the cytoplasm.

SECOND STEP: Translation


  • It's all in the name! Translating a speech from one language to another is like translating RNA nucleotides into a chain of amino acids.

  • Location: Cytoplasm/Ribosome

    • The cytoplasm consists of tRNA (transfer RNA) strands that each have an amino acid attached to it.

  1. The tRNA strands "read" the mRNA's bases in threes (codons) and bind to the mRNA if they are complementary.


      • Each tRNA strand is called an "anticodon".

      • Translation first starts at the start codon.

  2. While the tRNA strand leaves to find another matching codon, the tRNA will leave the amino acids behind, gradually making a long chain of amino acids.

  3. This continues until the stop codon indicates that the polypeptide (chain of amino acids) is complete.

[NOTE: The following explanation is extremely simplified.]

The final step differs for every kind of protein, but it typically requires multiple polypeptides to bond and fold into the shape of a specific kind of protein.


Here are the sources I used to make this study guide.

Feel free to look at these resources for more information!

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