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What is meant by a genome? A genome refers to all the DNA in a cell or organism - AQA - A-Level Biology - Question 8 - 2018 - Paper 2
Question 8
What is meant by a genome? A genome refers to all the DNA in a cell or organism. This includes all its genes, alleles, and genetic material that make up the complet... show full transcript
Worked Solution & Example Answer:What is meant by a genome? A genome refers to all the DNA in a cell or organism - AQA - A-Level Biology - Question 8 - 2018 - Paper 2
Step 1
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 is complementary to the shape of the transcription factor. This complementary fit ensures that the antibody can specifically recognize and attach to the transcription factor during the chromatin immunoprecipitation process.
Step 2
Use Figure 8 to explain what 'precipitated DNA' consists of.
Answer
The 'precipitated DNA' consists of DNA fragments that have been specifically bound to the transcription factor through the use of antibodies. This ensures that only the DNA associated with the transcription factor is isolated during the immunoprecipitation process.
Step 3
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 corresponding mRNA sequence produced by the gene. This binding inhibits the translation process, effectively silencing the gene expression.
Step 4
Describe the roles of two named types of enzymes used to insert DNA fragments into plasmids.
Answer
- Restriction enzyme: This enzyme is used to cut the plasmid/vector at specific recognition sites, allowing for the insertion of the desired DNA fragment.
- Ligase enzyme: This enzyme facilitates the joining of the DNA fragment into the plasmid/vector by forming phosphodiester bonds, thereby ensuring the new DNA is stable and correctly integrated.
Step 5
Suggest two features of the structure of different proteins that enable them to be separated by gel electrophoresis.
Answer
- Mass/number of amino acids: Proteins of different sizes will migrate at different rates through the gel, allowing for separation.
- Charge: Proteins have varying charges based on their amino acid composition, which affects their movement in an electric field used during electrophoresis.