The origin is the place where DNA replication begins. Helicase, the enzyme breaks the hydrogen bonds that hold the bases of the DNA together comes in. It unwinds the DNA.
This is a picture of the DNA strands before it is replicated and unwinded. It’s called the DNA double helix structure. The polygons and hexagons represents the nucleobases Adenine, Thymine, Guanine and Cytosine. Each one is paired with it’s complimentary pair and is bonded by hydrogen bonds. (The black dots represents the hydrogen bonds bonding them together)
To keep the strands separated after the unwinding, SSB proteins (single stranded binding proteins) will bind to them. To keep the enzyme from coiling too much (when the DNA strand is too compact) an enzyme called topoisomerase binds to the strands. DNA primase is what makes the primer, meaning it chooses where the DNA polymerase replicates the DNA molecules. The leading strand is the new strand that is being formed right behind the unwinding of the DNA. The lagging strand is the other strand, and it stops when the leading strand stops. This causes fragments that are called Okazaki fragments. Ligase is the enzyme that glues the gaps between the fragments. It makes a primer on both strands. DNA polymerase then comes in and is building a new strand.
Here is the double helix being unwinded.
Protein synthesis is a fundamental process that is what keeps us alive. It starts out with DNA causing a protein to be produced. DNA carries the instructions to make proteins. The first step that occurs in protein synthesis is transcription.
The definition of transcription is to transcribe the DNA into a message. Your cells all contain DNA, which is kept in the nucleus. In the nucleus, there is something called the genome. The genome is split between chromosomes, each chromosome has long strains of DNA wrapped around proteins. These proteins are called histones. Within the DNA spaces contain Genes and these genes are so important because provide instructions for the formation of proteins. RNA polymerase is an enzyme and will connect complementary bases to the DNA. It sticks to the start of the gene when it gets switched on. From the free bases of the nucleus, it makes a strand of messenger RNA as it moves along DNA. . From the nucleus the messenger RNA then then moves into the cytoplasm. Ribosomes is a structure made of both RNA and protein that’s located in the cytoplasm. These ribosomes bind to the messenger RNA and reads a code, then produces a chain made of amino acids. Eukaryotic messenger RNA is the substrate for translation, it contains codons for specific amino acids. A triplet (3 bases of messenger RNA) is what codes for a certain amino acid. Initiation begins when the subunit of the ribosome attaches to the messenger RNA and goes to the translation initiation site.
Transfer RNA’s role is to link the messenger RNA and the amino acid chain. It contains anti codon that’s complimentary to the messenger RNA it binds to. It carries the amino acids to the ribosome. The amino acid is attached to the end of the Transfer RNA. Each Amino acid has a corresponding codon. Now, the large subunit of the ribosome binds and creates the P site (peptidyl) and the A site (aminoacyl site). Messenger RNA gets read 3 bases at a time (anti codon) and while this is happening the transfer RNA gives the corresponding amino acid, which is added to a growing chain of amino acids. When the codon and anti codon pair, it transfers the amino acid it was carrying. The first transfer RNA goes to the P site and the second transfer RNA goes to the A site. Then, the amino acid that has a corresponding codon is transferred to the amino acid from the A site. After it is transferred, the first transfer RNA leaves and so on, the cycle continues.
In the model above, the purple cubes are the amino acids. The green paper is the transfer RNA and the white strand of bases is the messenger RNA. As you can see, the transfer RNA is carrying the amino acids and 3 bases of messenger RNA gets paired with 3 bases of anti codon. Anti codon is found on the end of the Transfer RNA, it’s very important because that’s how it brings the correct Amino acid.
The ribosomes move along the messenger RNA, new transfer RNA enters, and the peptide (chain of amino acids) grows longer. The transfer RNA will eventually leave but it leaves the amino acid it was carrying. This process is called elongation.
Termination is when translation is terminated. This occurs when the release factor, a stop codon enters the A site and stops the translation. After all the amino acids get added, this chain folds into a 3d shape to form the protein. The ribosome dissociates and the new protein is released.
Here is a picture of the amino acid Chain after it has detached from the the ribosome.
In what ways did your models accurately reflect the process?
Protein Synthesis is process that happens in our bodies all the time, it’s something extremely small which is why it is so difficult to visualize and comprehend because we can’t physically see it. Our groups was able to show the main steps of protein synthesis through the hands on activity and this accurately reflected the process. The cut out shapes from the model helped us gain a better understanding because we were able to visualize how each structure looked liked and where it was. On top of that I found the color coded paper helped a lot in identifying the different parts in protein synthesis. In my opinion the model really helped me understand transcription because I found it so difficult to understand. The activity really helped me to visualize the process.
In what ways did your model misrepresent the process?
Our models only showed us the key steps of protein synthesis and it was lacking many details so if you were to look at the model for an in-depth explanation of protein synthesis, you wouldn’t get that. The model was only there to help us understand protein synthesis more, in real life it is way more complex then a few pieces of paper.
What changes could be made to the modelling activities to make them better represent the actual process?
Changes that could be made for the modelling activity to make them better represent the actual process is labelling each piece of paper to help students better remember what structure it is representing. They may be just reading the instructions and doing the activity without really knowing which object is which and why it is going there. Another thing is each group having all the paper/material they need in a bag, it would be more efficient and less messy. That way they wouldn’t need to go to other groups for a paper they don’t have and they wouldn’t need to go back an forth to put things back.
Models are commonly used to communicate scientific concepts to non-scientific audiences. Do you think this is an effective way to educate the public about science? Explain why or why not..
I think that this is a very effective way to educate the public about science because often times scientific concepts are very hard to understand. Non scientific people don’t know scientific terms so they wouldn’t know where it is located, what it’s function is or how it looks like, which is why if you just gave them an explanation they probably would not understand. Take me for example, I am a visual learner and the only way I understood Protein Synthesis was through watching videos of the process. I could not read anything because I could only remember and understand each step with an image in my mind.
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