Term
| Q1. What is phosphorylation? |
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Definition
| Phosphorylation involves the covalent addition of a highly charged (3‐) phosphate group to a protein, for example. |
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Term
| Q1. How does phosphorylation of a protein influence the function of the protein? |
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Definition
| Phosphorylation can activate or inactivate a functional protein by altering the conformation of the protein and by altering the ability of the protein to bind with other accessory proteins vital to the specific function. |
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Term
| Q1. Give an example of a specific protein and explain how its function is altered by phosphorylation. |
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Definition
1. CPEB - fertilization triggers the phosphorylation of this protein, activating the transcription of previously dormant mRNA in oocytes.
2. RNA polymerase - The carboxy terminal domain of the enzyme gets phoshorylated upon completion of the assembly of the pre‐initiation complex activating RNA transcription. |
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Term
| Q2. Describe how Pipe protein synthesis by the follicle cells is controlled by the oocyte during Drosophila oocyte development. |
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Definition
| gurken mRNA is associated with the oocyte nucleus. Gurken protein does not diffuse far and is synthesized near, and secreted from, the dorsal anterior of the oocyte. Secreted Gurken activates the Torpedo receptor on the follicle cells. The Torpedo signaling results in the inhibition of Pipe protein synthesis in the dorsal follicle cells. |
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Term
| Q2. How does control of this protein influence the generation of the Dorsal --> Ventral axis in the early Drosophila embryo? |
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Definition
| Only ventral follicle cells make Pipe proteins, which when secreted from the ventral follicle cells initiates a signaling cascade that activates Dorsal protein on the ventral region of the developing fly embryo. As the fly embryo develops into the syncitial blastoderm, Dorsal protein can enter nuclei on the ventral side, distinguishing these nuclei from the dorsal nuclei. The Dorsal protein gradient distinguishes cell fates along the D --> V axis. |
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