Proteins – Cell Facts

What are proteins?

Proteins are chains formed out of amino acids. Amino acids are chains of molecules such as oxygen, carbon, nitrogen, and hydrogen. Ribosomes and other cell organelles make proteins by chaining amino acids together, according to the instructions in DNA and RNA.

Which cell organelles make proteins, and how?

Chromatins are structures in the nucleus that contain proteins and genetic material, such as DNA.

In the matrix, mitochondria store their own proteins, ribosomes, and DNA.

Ribosomes generate proteins from the DNA in the nucleus to help the cell function. They can also attach themselves to the cell membrane, where they can create the proteins that make up the structures of the cell membrane.


The structures within the cell membrane, such as channels for substances to flow through, are made of proteins.

The large subunit of a ribosome is important in the creation of new proteins, and it’s the site where protein bonds are made. The small subunit of a ribosome is only slightly smaller than the large subunit in reality, but its primary function is to help information flow during the synthesis (creation) of new proteins.

The primary function of a ribosome is the creation of new proteins, a process called protein synthesis. There are hundreds or even thousands of different types of proteins that the cells need for their various functions, and ribosomes are responsible for making all of them as needed.

To make each kind of protein when it is needed, the ribosomes need a specific list of instructions. This list comes from the RNA, or the genetic material that comes from DNA. There are codes written in the RNA for each protein, so that the ribosomes can make the right ones.

There are two processes involved in protein synthesis. One is called transcription, and the other is called translation. Ribosomes are specifically responsible for the translation step of protein synthesis.

Chemical structure of the peptide bond

What is transcription?

Transcription is the first step in the protein synthesis process. During this phase, the cell will copy (or transcript) the DNA to duplicate it. The copy of one strand of DNA is called RNA. While DNA is deoxyribonucleic acid, RNA is simply ribonucleic acid.

What is translation?

In the second step of protein synthesis, translation, the ribosomes take the list of protein making instructions from the RNA to create new proteins for cell use. The first step is the two subunits of the ribosomes, the small and large subunits, joining with the RNA.

Then, the ribosome identifies the starting position of the coded list of instructions in the RNA, called a codon. Next, the ribosome continues processes each section of the RNA, learning which amino acids must be linked together to form the protein.

Amino acids are the building blocks of proteins, and they are listed in groups in DNA and RNA. Once the ribosome finishes linking together the appropriate amino acids in the protein building process, it will reach a “stop” signal in the RNA, similar to the “start” signal found.

ribosome producing a protein


  1. What are proteins?
  2. What are amino acids?
  3. Which organelle is the primary one known for making proteins?
  4. What are cell proteins used for?
  5. What are the two steps of protein synthesis?


  1. Proteins are chains of amino acids.
  2. Amino acids are chains of molecules used to make proteins.
  3. Ribosomes make proteins.
  4. Proteins are used to make the structures of the cell membrane and used in the functioning of the cell.
  5. The two steps of protein synthesis are transcription and translation.