46889
Description
Flashcards by Mark Arsenal, updated more than 1 year ago
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Created by Mark Arsenal
about 11 years ago
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| Question | Answer |
| What are the 3 stages of the Translation phase? | Iniation, Elongation, Termination. |
| What is the purpose of Transamination and Deamination? | Allows the formation of required AA's for prtotein synthesis or to Alpha-Ketoacids for entry into energy producing pathway. |
| What is Transamination? | Transamination is the transfer of Amino group from an unnecessary AA to make a required one. Results in a useful AA and a Alpha-Ketoacid. |
| What is Deamination? And where does it occur? | Deamination is the removal of an Amino Group to form an Alpha Ketoacid and Ammonia. Ammonia is toxic and needs to be removed which is achieved through conversion into urea and urinated out. Glutamate facilitates the removal. Deamination occurs in the liver. |
| How can Alpha-Ketoacids be used for energy? | They can be directly metabolised, The carbon chain (R-group) can be broken down to form TCA intermediates. It can also be broken down to form Pyruvate which is broken down to form Acetyl CoA whereby it can enter the TCA cycle for energy production. |
| What cycle helps in ammonia removal? | Glucose Alanine Cycle. This is a process whereby we remove a Ammonia molecule and receive a Glucose molecule in exchange. This helps maintain Glucose levels when demand is high. |
| Protein Synthesis Steps: | Gene-Expression ----> Transcription ---->Translation ----> Post Translational Processing |
| What does Post Translational Processing Involve? | After Polypeptide chainis released it needs additional processing before its in its functional location, in its active form, or in its functional shape (some fold naturally, others require help) |
| How does the body know where the proteins functional location is? | By a signalling protein which is at the start of the proteins polypeptide chain. Most Signalling Proteins are directed to the Sarcoplasmic Reticulum. If there is no signalling protein they are directed to the cytoplasm. |
| What do Molecular Chaperones do? | They bind to and fold the Polypeptide Chain to its final conformation. |
| What do Scaffolding Proteins do? | They transport proteins across the Mitochondrial Membrane |
| Why do we break down proteins? | Quality Control, Protein Turnover (Two types, Fast= Turned over every hour and Slow= Turned over every few days/weeks) and for Muscle Growth (Protein Degredation speeds up muscle growth through provision of AA for Protein Synthesis). |
| Proteins for Energy? | Proteins can be broken down into AA's which can be transaminated/deaminated into Alpha Ketoacids for energy production (broken down into Pyruvate) in the TCA Cycle or enter Gluconeogenesis for Glucose production. Proteins only account for 5% of energy and are spared by availability of CHO. |
| What pathways break down proteins? | Lysosomal (Proteins are engulfed by Lysosomes) Caspases (Cell Death) Calpain (Calcium activated breakdown of proteins) and the Ubiquitin-Proteasome Pathway. |
| Which protein breakdown pathway is most used? | Ubiquitin-Proteasome Pathway- It accounts for 80-90% of protein breakdown and maintains protein balance by killing bad proteins and keeping good proteins. |
| What are the steps in the Ubiquitin-Proteasome Pathway? | 1) Ubiquitin recognizes the protein for degredation, binds to it and regulates quantity of protein. 2) E1 Activates Ubiquitin 3) Allows for attachment of Ubiquitin to protein, which allows chain of Ubiquitin to form on the protein. This chain signals for Proteasome to breakdown the protein to AA's. (Thus it is E3 that regulates specificity of protein breakdown) |
| Amino Acids (AA's) are the building blocks of proteins. | AA's are formed of 3 components, an Amino Group, R Group (carbon chain) and Carboxyl Group |
| How do we break down AA's? | By Transamination or Deamination. Where the Amino Group is removed to form Alpha-Ketoacids. |
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