Two students use equal masses of the same fruit to extract DNA. Both filter their mixtures and add cold ethanol. Student P uses detergent solution. Student Q replaces the detergent solution with the same volume of water.
Student Q collects less DNA. Which explanation is most likely?
More DNA dissolves in ethanol, so less DNA enters the filtrate.
More membranes remain intact, so less DNA enters the filtrate.
More DNA is made by detergent, so less DNA enters the filtrate.
More bases are removed by water, so less DNA enters the filtrate.
44 exam-style questions on Edexcel GCSE Biology 3.2 DNA and protein synthesis, covering 3.2.1 DNA structure as a polymer, 3.2.2 Genome and gene definitions, 3.2.3 Extracting DNA from fruit, 3.2.4 Base order determines protein shape, 3.2.5 Stages of protein synthesis, 3.2.6 Non-coding DNA variants affecting phenotype, and 3.2.7 Coding DNA variants affecting phenotype. Each one has a worked solution and a mark scheme showing where the marks go.