How does the brightness of a quasar compared with that of a large galaxy?

The extraordinarily bright luminosity is generated by the ultraluminous nuclei, of a far distant galaxy.

Explanation:
The fibrous quasar-fuzz reveals that the extraordinarily luminous star-like quasar is in a far distant galaxy. The point source of light called quasar is surmised as nuclei of the galaxy, appearing as a fuzz surrounding the quasar.

Luminosity of a quasar might be as large as 100000 times the luminosity of our galaxy Milky Way (MW). For a contrast: Sun;s luminosity L = 1 is about 1/(250 million) of MW luminosity.

What is observed as a quasar now is a revelation of what i was about billion(s) years ago.

Air enters through the nose (and sometimes the mouth), moves through the nasal cavity, the  pharynx, the  larynx, enters the  trachea, moves through the  bronchi  andbronchioles  till the alveoli.