Term
| What is a protein domain? |
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Definition
| Protein domains are areas of proteins which have different tasks. They may vary in secondary structure (alpha helix v. beta sheet). |
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Term
True or false? Domains of the same type have different structure if found in different proteins.
If true, give an example. |
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Definition
True, they will differ slightly in AA sequence, but will have similar overall shape and function.
The Helix-turn-helix (HTH) domain is part of transcription factors and binds to the operator in bacteria genes. Different AA sequences of the HTH domain in different proteins allow them to bind to different operators. |
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Term
| What does the SH2 domain do in proteins? |
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Definition
| The SH2 domain binds to phosphorylated tyrosine kinase receptors in cell membranes. |
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Term
| True or false? All cancer has unregulated cell division and results from mutations. |
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Definition
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Term
| Mutations in which two types of proteins can cause cancer? |
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Definition
1. Cell division regulators
2. Tumor suppressors |
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Term
| Name two cell division regulating proteins that can cause cancer if they develop mutations. What do each of them do? |
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Definition
1. PDGFR (a cell membrane tyrosine kinase receptor) can signal kinases even without having the PDGF growth factor binded.
2. The RAS protein can send signals to other proteins without receiving one. |
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Term
| What is the relationship between oncoproteins, oncogenes and proto-oncogenes? |
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Definition
| Oncogenes are mutated genes which code for oncoproteins that can cause cancer. Proto-oncogenes are normal genes that become oncogenes when mutated. |
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Term
| What is p53 an example of? What does it do? |
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Definition
p53 is a tumor suppressor that stimulated transcription of genes whose proteins limit the effects of DNA damage by:
1. Slowing the cell cycle
2. Repairing DNA
3. Killing the cell if damage is too severe (apoptosis) |
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