The Basics

Synthetic Biology, Explained

Watch this video that helps explain the focus of this club: Synthetic Biology

DNA or DeoxyriboNucleic Acid, is life's way of storing information. It provides the instructions for your body on how to run properly, how to grow, and when to sleep. It is like the programming code of life.
If we modify an organisms DNA, it is like editing the code of a computer program. It causes the organism to act differently. Scientists have realized that this can be used to our advantage. For instance, we can make E.Coli, a cell that normally doesn't do anything useful for us, produce insulin, a life-saving enzyme.

A plasmid is a circular ring of DNA that can be found in bacterial cells. These are sort of like modifiers for the main DNA code--they often contain the genetic information for a trait that gives a certain bacterium a genetic advantage, such as antibiotic resistance. Plasmids replicate independently from the main DNA, and bacteria can also transfer them to other bacteria through a process called conjugation.
Our goal is to modify an existing plasmid or insert a new plasmid into a bacterium. They are the easiest to modify and will not affect a bacterium's ability to carry out normal functions properly if manipulated. A plasmid that is used for the purposes of manipulating and experimentation is called a vector

DNA provides the instructions for how to build a protein
Ribosomes are responsible for actually making the protein
The information stored in DNA needs a way to be transferred to the ribosomes, so the ribosomes know how to make the protein
- this task is fulfilled by mRNA, or messenger RNA (Ribonucleic Acid). It is a temporary copy of the information stored in DNA
An enzyme called RNA polymerase copies the DNA to make an mRNA strand.
This mRNA strand then travels towards a ribosome, in which its data is read and the protein is produced

An operon is a functional unit of DNA. It holds instructions for a single task. Take the Lac operon as an example.
- Lactase is an enzyme that is responsibe for breaking down lactose, a sugar found in milk
- The LCT gene codes for lactase. It provides the instructions for how to make a lactase enzyme.

The promoter essentially enables the cell to express the trait that the gene holds. Without the promoter, the gene cannot be expressed, and as such it is a vital part of your design
Promoters are differentiated by how often they are activated
- Constitutive promoters are always on, meaning that the gene is always expressed. For certain cases, such as wanting a cell to secrete a certain enzyme like Insulin, you would want your plasmid to have a constitutive promoter
- Other promoters are activated/deactivated based on environmental factors. You can find a list of them on IGEM.org!

The Ribosome Binding Site (RBS), which comes after the promoter (downstream) and before the coding sequence (upstream), is responsible for recruiting the ribosome, which essentially is responsible for the actual production of the protein you want to be produced. For all that you are concerned with, a Ribosome Binding Site is necessary.
RBS are categorized based on the level of their affinity for ribosomes (strong, medium, weak)
- Strong RBS result in the highest gene expression. Once again, this would come in handy if your project depends on the secretion of a protein
- The other types of RBS are pretty self-explanatory. Simply choose the type that best suits your project!

The coding sequence is probably the most simple of the codon parts: it is the part of the gene that actually codes for your protein. This is the star of your project; it is what you have been researching for
For example, the GFP gene is the coding sequence for the GFP protein. All the other stuff (promoter, ribosome binding site, terminator) is just there to ensure that it gets expressed properly

The terminator ends your sequence. Simply find a terminator that is compatible with your host cell, and you're all set!

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