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1. What is meant by a genome? 2 - AQA - A-Level Biology - Question 8 - 2018 - Paper 1
Question 8
1. What is meant by a genome? 2. Explain why the antibody binds to the transcription factor. 3. Use Figure 8 to explain what 'precipitated DNA' consists of. Soybe... show full transcript
Worked Solution & Example Answer:1. What is meant by a genome? 2 - AQA - A-Level Biology - Question 8 - 2018 - Paper 1
Step 1
Step 2
Explain why the antibody binds to the transcription factor.
Answer
The antibody binds to the transcription factor because it has a specific, complementary structure that allows for this interaction. The binding occurs at a variable region of the antibody, which is designed to recognize and attach to the unique structure of the transcription factor.
Step 3
Use Figure 8 to explain what 'precipitated DNA' consists of.
Answer
Precipitated DNA consists of DNA that has been isolated from a solution, typically using alcohol or other precipitating agents. This process separates DNA from other cellular components, resulting in a more concentrated form that is visible as a white, stringy precipitate.
Step 4
Suggest how single-stranded cDNA could prevent transcription of the P34 gene.
Answer
Single-stranded cDNA can prevent transcription of the P34 gene by binding to the mRNA produced from that gene. This binding prevents the ribosome from recognizing the mRNA, effectively blocking its translation into the P34 protein.
Step 5
Describe the roles of two named types of enzymes used to insert DNA fragments into plasmids.
Answer
- Restriction enzyme: This enzyme recognizes specific sequences of DNA and cuts the plasmid at these sites, creating sticky ends for insertion.
- Ligase: This enzyme joins the DNA fragment to the plasmid by forming bonds between the sugar and phosphate backbones, sealing the new DNA into the plasmid structure.
Step 6
Suggest two features of the structure of different proteins that enable them to be separated by gel electrophoresis.
Answer
- Mass/size: Proteins of different sizes will migrate at different rates through the gel matrix. Larger proteins move slower than smaller ones.
- Charge: The overall charge of a protein affects its movement in the electric field used during electrophoresis; proteins will migrate towards the electrode of opposite charge.