Structure predicts function
AP questions often ask you to move from molecular structure to a testable prediction. Identify polarity, charge, bonding, shape, or arrangement; explain the physical interaction; then connect it to function. Distinguish observations from conclusions and compare treatments that differ in the variable of interest. A change correlated with function does not establish that it is the only cause. Use appropriate controls and repeated measurements. Biological molecules work in a particular environment, so a structure that is useful in one setting can behave differently after pH, temperature, or surrounding molecules change.
If a normally soluble protein becomes less soluble after exposed polar residues are replaced with nonpolar residues, a reasonable mechanism is reduced favorable interaction with water and increased aggregation. “Its shape changed” alone is too vague.
Do not jump from a changed molecule to “the organism dies” unless the evidence supports that scale of effect. Explain the nearest supported consequence first.