F.4 Biology question (10分)

a. The cell membrane is a selectively permeable membrane enclosing the cell. The membrane have pores through which only particles small enough (e.g. glucose) can pass through and get into the cell and restrict the entry of substances that are too large to pass through.



b. A thin sample of sample should be obtained (thin, so that light may penetrate through). The sample should be put carefully on a slide and stained, so that the structures of the cells can be seen easily. put a drop of mountant (e.g. water, glycerol) on it and put cover slip over it (one side first then the other) to prevent the cell from drying up.