Patients with Duchenne muscular dystrophy (DMD) lack a functional structural protein called dystrophin in their muscle cells. However, muscle cells contain a gene for a homologous protein called utrophin, which can functionally compensate for the lack of dystrophin but is normally switched off shortly after birth.
A regulatory gene called UPR-1 produces a repressor protein that actively blocks the transcription of the utrophin gene in adult muscle tissue.
How could a therapeutic treatment targeting the UPR-1 pathway be used to treat patients with DMD?
Genetically engineering muscle cells to introduce multiple extra copies of the active UPR-1 gene.
Preventing the expression of the UPR-1 gene, allowing transcription of the utrophin gene to proceed.
Upregulating the translation of UPR-1 mRNA in the cytoplasm to increase the concentration of the repressor protein.
Deactivating all ribosomes in the skeletal muscle cells to completely stop UPR-1 protein synthesis.
72 exam-style questions on OCR GCSE Biology 1.2 What happens in cells (and what do cells need)?, covering 1.2.1 Structure of DNA, 1.2.2 Nucleotides and complementary bases, 1.2.3 Protein synthesis, 1.2.4 DNA structure and the proteins made, 1.2.5 Investigating enzymatic reactions, and 1.2.6 Mechanism of enzyme action. Each one has a worked solution and a mark scheme showing where the marks go.