Gene expression 3.0 / 5 based on 1 rating ? BiologyDNA, genetics and evolutionA2/A-levelAQA Created by: LZ95Created on: 13-05-14 19:39 How do differentiated cells differ from each other? They produce different proteins 1 of 17 What are totipotent cells? Cells that can mature into any type of body cell 2 of 17 Name 2 ways in which gene expression can be stopped 1. Preventing transcription (no mRNA) 2. Breaking down mRNA before it is translated 3 of 17 What are stem cells? Undifferentiated dividing cells occurring in adult animal tissues. 4 of 17 Name 3 places where stem cells can be found 1. Inner lining of small intestine 2. The skin 3. The bone marrow 5 of 17 Why are stem cells useful? In the right conditions they can be used to treat a variety of genetic disorders. 6 of 17 How are stem cells different in plants? Many plant cells can develop into any other type of cell. 7 of 17 What are transcriptional factors? Specific molecules which stimulate genes to move from the cytoplasm to the nucleus. 8 of 17 How does a transcriptional factor stimulate transcription? It binds to a specific region of the DNA in the nucleus. 9 of 17 What happens to a transcriptional factor when a gene is not expressed? An inhibitor molecules binds to the binding site of the transcriptional factor so transcription cannot occur. 10 of 17 Why does oestrogen diffuse easily through the phospholipid portion of cell surface membranes? As it is lipid soluble. 11 of 17 What does oestrogen bind to when in the cytoplasm? The site on the receptor molecule of the transcriptional factor. 12 of 17 How does oestrogen prevent the inhibitor from stopping gene expression? It changes the shape of the receptor molecule so the inhibitor is released from the DNA binding site. 13 of 17 What is siRNA? Small sections of cut RNA. 14 of 17 How does siRNA guide an enzyme to mRNA? By pairing up complementary bases on a section of the mRNA. 15 of 17 How does the enzyme attached to siRNA prevent translation? It cuts mRNA into smaller sections so it can no longer be translated into a polypeptide. 16 of 17 Name two uses of siRNA 1. Blocks genetic diseases 2. Used to identify role of genes in a biological pathway 17 of 17
Comments
No comments have yet been made