This week my friend, the doctoral candidate and fellow crazy person, asked me the question dreaded by scientists around the world: is it effect or affect? (A question more annoying than usual since we science types use the rare ‘effect as a verb’ )
So I look it up. Again. And we decide that she should use effect when she is referring to experiments that cause an effect and affect when she is referring to experiments that influence an effect. This is an incredibly subtle difference, so allow me to illustrate…
Transfecting the cells effects the transcription of the gene – this says “we’re putting something in the cell and it will turn the gene on”.
Unloading the heart affects the transcription of the contractile genes – this says those genes are already in effect in the heart, but changing the environment influences their effect.
So when in doubt on which word to use, consider your experiment. If it directly proves or disproves your hypothesis, use effect. If it is more of a descriptive experiment, use affect.