Aqa A Level Biology Paper 3 2022 Already Passed

What are the advantages of using mRNA rather than restriction enzymes to cut the gene from DNA? {Ans: More mRNA in cell than DNA → easily extracted Introns removed by splicing (DNA contains introns).}Describe and explain the differences between rods and cones in response to light. {Ans: Rods are more sensitive to light. Rods connected in groups to one neurone (retinal convergence). Spatial summation. Stimulation of each individual cell alone is insufficient but cells connected in groups so threshold more likely met to generate AP. Cones are less sensitive to light. One cone joins to one neurone. No spatial summation.}What is the process of binary fission. {Ans: DNA and plasmids replicate. Cytoplasm extends and each copy of DNA (and variable number of plasmids) move to opposite poles. Cytoplasm divides. 2 daughter cells produced.}3.4.2 DNA and Protein Synthesis {Ans: }3.8.4 Gene Technology {Ans: }3.2.2 All Cells Arise from Other Cells {Ans: }What are the stages of protein synthesis? {Ans: Transcription and translation.}How does a pacinian corpuscle work? {Ans: Mechanical stimulus (pressure deforms lamellae and so opens stretch-mediated sodium ion channel). Na+ channels open and Na+ diffuse into sensory neurone. More pressure -> more