AQA A Level Biology 4/5/6 mark questions (2024/2025) Exam Questions and Answers 100% Solved

AQA A Level Biology 4/5/6 mark questions (2024/2025) Exam Questions and Answers 100% Solved Many different substances enter and leave a cell by crossing its cell surface membrane. Describe how substances can cross a cell surface membrane. (5) 1 (Simple / facilitated) diffusion from high to low concentration / down concentration gradient; Small / non-polar / lipid-soluble molecules pass via phospholipids / bilayer; OR Large / polar / water-soluble molecules go through proteins; Water moves by osmosis / from high water potential to low water potential / from less to more negative water potential; Active transport is movement from low to high concentration / against concentration gradient; Active transport / facilitated diffusion involves proteins/carriers; Active transport requires energy / ATP; Ref. to Na+ / glucose co-transport;