Mad Cow (bovine spongiform encephalopathy)
Mad cow disease, or bovine spongiform encephalopathy, is a transmissible, slowly progressive, degenerative, and fatal disease that affects the nervous system of adult cattle. Once the cattle become infected with the disease humans can get it by eating meat from mad cows. Once the meat is consumed it will alter the prions in the human brain. When a cow consumes meat from another cow that had mad cow disease it will change a protein in the brain called a prion. For unknown reasons, the prion then destroys the nervous system tissues, the brain, and the spinal cord. After translation, unknown changes occur which lead to abnormal secondary and tertiary folding.
Brain of a healthy cow vs. a cow with the disease
Summary:
In this project we described how a protein can cause a disease by looking at the process of protein synthesis. We also looked at normal and diseased proteins and learned some general info on the disease. We showed this information by give a creative presentation on our understanding of the disease, the protein, and protein synthesis.
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Whats the difference between
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Definitions:
- Proteins: Proteins are used to build and repair tissues. They make enzymes, hormones, and other body chemicals. They help to build bones and muscles. They are made in the process of protein synthesis. During protein synthesis errors can occur and this leads to diseases like Mad Cow.
- Codon/Anticodon: The codon is a set of three bases from a mRNA. They are read by the tRNA which matches the codon with an anticodon. The anticodon is three bases from the tRNA. If the codons and anticodons do not match correctly the protein can become diseased. For Mad Cow disease, scientists are unsure how the prion changes but they believe that it happens during the folding process.
- Polymerase: Polymerase is an enzyme that is used during protein synthesis. They help to assemble DNA and RNA and they help to synthesis long chains of nucleic acids.
- Polypeptide chain: When the amino acids are put together in the ribosome they form a chain called the polypeptide chain. The chain is what turns into the completed protein during the protein folding step.
- Alpha helix/Beta sheet: Alpha helix and beta sheets are formed during the secondary structure of protein folding. They are folded by hydrogen, hydrophilic, and hydrophobic bonds. When a prion misfolds there are more beta sheets while a normal prion has mostly alfa sheets. When this misfolding occurs it leads to a prion caused disease like Mad Cow.
- Prion: Mad cow disease changes the protein called a prion and makes it abnormal. It then destroys nervous system tissues, the brain, and the spinal cord. Scientists are not sure why the disease alters the protein. Prions are found in the brain and they are common in most brain related diseases.
- Amino Acid: The amino acid is a monomer for a protein. When you put a bunch of amino acids together in a chain it forms a protein. There are 20 different types of amino acids that make up many different types of proteins.
- mRNA: In the nucleus, mRNA is made by the DNA. It is known as the messenger RNA and goes to the ribosomes during the process of transcription to make a protein.
- tRNA: The tRNA brings amino acids to the ribosome. It reads the codons from the mRNA and adds a amino acid based on the what the mRNA reads.
Protein Synthesis and Folding:
There are two steps in protein synthesis: transcription and translation. After the protein synthesis process the protein starts to fold.
Transcription is when the DNA sequence information is being converted to RNA, where a segment of DNA is copied into RNA. The double strand DNA molecule that is partially ‘unzipped’ has RNA polymerase copy the DNA’s nucleotides one by one turning it into an mRNA molecule. Unlike DNA, RNA has only a single strand, and is a more fragile and temporary molecule inside the cell. RNA is small and can easily exit the nucleus and go to the cytoplasm, where proteins are made. The mRNA leaves the nucleus to go to the cytoplasm and attach to ribosomes.
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Translation is the process where the RNA molecule (nucleotide sequence) is now decoded into an amino acid sequence (protein). Ribosome matches the mRNA code in sets of three bases called codons. This creates tRNA with matching anticodon bases. The ribosome moves the mRNA along matching 3 base pairs each time and adding to a polypeptide chain. When the ribosome reaches a stop code it will release the mRNA and the new polypeptide chain. The chain forms its nature shape and goes into the cell to serve its function as a protein.
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The protein will move and change until it has found its most stable state. It is guided by hydrophobic interactions and bonds between hydrogen molecules. For the Primary Structure It starts with the amino acid chain and the location of the amino acid determine where it will fold.
In the Secondary Structure Hydrogen bonds quickly fold parts of the protein and they help to develop stability within the protein. It then creates Alpha helix and beta sheets that fold in the rough ER. The Tertiary Structure has Hydrophobic and hydrophilic reactions that allow the protein to fold more towards the core that is hydrophobic. The Quaternary Structure is formed by Multiple polypeptide chains joining together to form larger protein structures. This step Occurs in golgi body. |
3D Model of a Prion
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Prion Code:
Reflection:
Something that went well was the research part of the project. We were able to finish all our research in a time efficient way so when we had to work on our video we had enough time to finish it. Something that went poorly was the voice overs for our video. We used the google voice for them and next time we could find a better voice to use. The google voice didn't pronounce words correctly and had a weird way of speaking.
I learned that the visual parts of a video can be difficult. We spent a lot of time doing research for this project so our voice overs were long. We had a hard time finding pictures or video clips to go with the audio. I also learned that you sometimes have to put some time into research on the internet before you can find an answer. A large part of this project we had to research prions and scientists know very little about them. We had to look through a multitude of websites before we were able to find what we were looking for.
One thing I could improve on is doing some research on the disease we picked before the project. We didn't realise that our disease was very similar to Creutzfeldt Jakob disease until we had already done our research. Another thing I could improve on is writing down my sources. I add the sources I use to the bibliography most of the time but sometimes i'll take a little fact from a website and forget to cite it.
Some peaks from this project were when we were able to find the code for a prion. It was fairly hard to find information on prions so when we were given a website to use it was very helpful. We also divided up the tasks at the beginning of the project so we all were able to work at the same time. A pit was when we thought our video was deleted. The phone that was used to make the video started to not work and then the video disappeared. Lucky when the app reloaded the video was still there.
I learned that the visual parts of a video can be difficult. We spent a lot of time doing research for this project so our voice overs were long. We had a hard time finding pictures or video clips to go with the audio. I also learned that you sometimes have to put some time into research on the internet before you can find an answer. A large part of this project we had to research prions and scientists know very little about them. We had to look through a multitude of websites before we were able to find what we were looking for.
One thing I could improve on is doing some research on the disease we picked before the project. We didn't realise that our disease was very similar to Creutzfeldt Jakob disease until we had already done our research. Another thing I could improve on is writing down my sources. I add the sources I use to the bibliography most of the time but sometimes i'll take a little fact from a website and forget to cite it.
Some peaks from this project were when we were able to find the code for a prion. It was fairly hard to find information on prions so when we were given a website to use it was very helpful. We also divided up the tasks at the beginning of the project so we all were able to work at the same time. A pit was when we thought our video was deleted. The phone that was used to make the video started to not work and then the video disappeared. Lucky when the app reloaded the video was still there.