Module 7 Lesson 3 - 2
Completion requirements
Lesson 3 — Protein Synthesis
Central Dogma
Read pages 636 - 642
Proteins are large molecules made of amino acids. The order of the nucleotides in DNA provides the code that determines how the amino acids must be strung together to build a protein. A gene is a sequence
of nucleotides on the DNA strand that codes for the production of one or more proteins.
All organisms use the same basic mechanism to produce protein from its genes. This process is referred to as the "Central Dogma". To express a gene, the genetic information is passed from DNA to RNA to protein. Passing the genetic information from DNA to RNA is called transcription. Translation describes the process of passing the message from RNA to protein.
In the previous lesson, you learned the structure of DNA and the four nucleotides found in DNA. RNA structure is very similar to DNA except for the five carbon sugar molecules. RNA is ribonucleoic acid. Instead of deoxyribose sugar, RNA has ribose sugars in its structure.
RNA has four nucleotides, just as DNA does, but instead of thymine, it has uracil. This means cytosine pairs with guanine and adenine pairs with uracil in RNA molecules.
Unlike DNA, RNA is a single stranded molecule, but it comes in two types: messenger RNA (mRNA) and transfer RNA (tRNA).
All organisms use the same basic mechanism to produce protein from its genes. This process is referred to as the "Central Dogma". To express a gene, the genetic information is passed from DNA to RNA to protein. Passing the genetic information from DNA to RNA is called transcription. Translation describes the process of passing the message from RNA to protein.
DNA vs. RNA
In the previous lesson, you learned the structure of DNA and the four nucleotides found in DNA. RNA structure is very similar to DNA except for the five carbon sugar molecules. RNA is ribonucleoic acid. Instead of deoxyribose sugar, RNA has ribose sugars in its structure.
RNA has four nucleotides, just as DNA does, but instead of thymine, it has uracil. This means cytosine pairs with guanine and adenine pairs with uracil in RNA molecules.
Unlike DNA, RNA is a single stranded molecule, but it comes in two types: messenger RNA (mRNA) and transfer RNA (tRNA).
Comparing DNA and RNA
| Deoxyribonucleic Acid (DNA) | Ribonucleic Acid (RNA) | |
| Structure |
Double stranded
|
Single stranded
|
| Nucleotides |
Adenine = Thymine
Cytosine = Guanine |
Adenine = Uracil
Cytosine = Guanine |
| Sugar | Deoxyribose | Ribose |