Photo AI
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. 4. Su... 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 tertiary structure that allows it to interact specifically with the transcription factor's variable region. This specificity ensures that the antibody can accurately identify and bind to the transcription factor, facilitating processes such as gene regulation.
Step 3
Use Figure 8 to explain what 'precipitated DNA' consists of.
Answer
'Precipitated DNA' consists of DNA that has been separated out of a solution, typically through a process involving the use of alcohol, such as ethanol or isopropanol. This technique allows for the visualization and extraction of DNA from cellular components.
Step 4
Suggest how single-stranded cDNA could prevent transcription of the P34 gene.
Answer
Single-stranded cDNA could prevent transcription of the P34 gene by hybridizing with the mRNA transcript of the P34 gene. This binding would result in the formation of a double-stranded molecule, effectively blocking the transcription machinery from accessing the original mRNA and preventing further transcription.
Step 5
Describe the roles of two named types of enzymes used to insert DNA fragments into plasmids.
Answer
-
Restriction Enzyme: This enzyme cuts the plasmid vector at specific sequences, allowing the insertion of foreign DNA fragments.
-
Ligase Enzyme: This enzyme is used to join the DNA fragment to the plasmid, sealing the backbone and ensuring that the inserted DNA is stable and can replicate within the host cell.
Step 6
Suggest two features of the structure of different proteins that enable them to be separated by gel electrophoresis.
Answer
-
Size: Proteins vary in size, and smaller proteins move faster through the gel compared to larger ones, allowing separation based on molecular weight.
-
Charge: Proteins have different charges depending on their amino acid composition, which affects their migration through the gel in response to an electric field.