• If the concentration of sugar molecule is higher outside the membrane than the inside so it moves from where it is at a higher concentration to where there is a lower concentration of the sugar molecule and this is achieved by the help of a carrier protein as follows:
i) ‘First, a sugar (large) molecule attaches to a carrier protein in the membrane’. ii) ‘Then, the protein (specific to the sugar molecule) changes shape’. iii) ‘This releases the molecule on the opposite side of the membrane’.