Eukaryotic mRNAs differ from prokaryotic mRNAs in that they Eukaryotic mRNAs differ from prokaryotic mRNAs in that they a. usually contain more than one gene
b. are collinear with the genes that encode them
c. are not collinear with the genes that encode them
D. both a and c are correct

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.

request for reexamination