How are the tyrosine hormones different? they are composed entirely of lipids they are released only by the hypothalamus they contain amino acids they sometimes behave as proteins and sometimes as steroids?

c is the answer : )               your welcome

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.