1. What is meant by a genome? 2 - AQA - A-Level Biology - Question 8 - 2018 - Paper 1

The antibody binds to the transcription factor because it has a specific tertiary structure that allows for a complementary fit. This binding occurs at a variable region of the antibody, which recognizes a specific epitope on the transcription factor.

‘Precipitated DNA’ consists of DNA that has been separated from other cellular components. The process usually involves the addition of precipitating agents which cause DNA to clump together, making it easier to isolate. This often requires the removal of proteins and other contaminants to yield pure DNA.

Single-stranded cDNA can prevent transcription of the P34 gene by binding to the mRNA produced by the P34 gene. This binding blocks the normal transcription process and effectively silences the expression of the gene.

1. Restriction enzyme: This enzyme cuts the plasmid at specific recognition sites, creating openings for the insertion of DNA fragments.

2. DNA ligase: This enzyme facilitates the joining of the DNA fragment to the plasmid by forming phosphodiester bonds, completing the recombinant plasmid.

1. Mass/number of amino acids or polypeptides: Proteins with different sizes will migrate at different rates in the gel matrix.

2. Charge: Proteins have varying charges at specific pH levels, affecting their movement in an electric field during electrophoresis.