The cell membrane of the red blood cell will allow water, oxygen, carbon dioxide, and glucose to pass through. because other substances are blocked from entering, this membrane called

a perforated
b semi-permeable
c non-conductive
d permeable

B. semi-permeable

meaning: it is only partly permeable, not all substances can pass through the membrane.

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.