Does fitting to composition ruin quality

I'm pretty new to abode after effects I just wanted to know if fitting to composition ruins my video quality. I will give 3 examples then can someone tell me if either one ruins the quality or all.

1. Fitting a video thats 3840x2160 into a composition thats 1080x1920

2. Fitting a video thats 1080x1920 into a composition thats 3840x2160 

3. Fitting a video thats 1920x1080 into a composition thats 1080x1920 (rotating the video by +90 degrees)