The cell walls of a plant consist mostly of cellulose, a carbohydrate, which provides a strong structure. The cell membrane gets its structure primarily from lipids, and embedded proteins allow for material transport. Which of the following elements would be found in the lowest amounts in both the cell wall and the cell membrane?

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given bodies of water

pacific / arctic / indian / southern

[ a ] the caribbean sea

[ b ] the northern ocean

[ c ] the atlantic ocean

[ d ] the barents sea

with this being the given answers

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.