AQA A LEVEL BIOLOGY PAPER 1 2020 QUESTION PAPER

0 1 Figure 1 shows a cell from the lining of the ileum specialised for absorption of products of digestion. SGLT1 is a carrier protein found in the cell-surface membrane of this cell, it transports glucose and sodium ions (Na+) into the cell. Figure 1 . The action of the carrier protein X in Figure 1 is linked to a membrane-bound ATP hydrolase enzyme. Explain the function of this ATP hydrolase. [2 marks]