Penny: You know, not a lot of people know this. But the monoamine oxidase enzyme was discovered by a woman, Mary Bernheim.
*Amy and Bernadette look puzzled by Penny's knowledge*
Penny: That's right, my phone is just as smart as you guys!

Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your Ken can kiss my Barbie.

Raj: [to Amy] If you were having Sheldon's baby, would you really want him in the room?
Penny: Yeah, if he's in the room when they're making the baby, I'll give you $10.

Penny: I mean, who even reads Scientific American?
Leonard: It's kind of a big deal.
Penny: If it's such a big deal, how come the biggest celebrity they could get for the cover is a molecule?

Sheldon: *knocks three times* Amy, Bernadette, Penny. *repeats three times*
Bernadette: He's never going to stop doing that, is he?
Amy: I don't mind. I'm hoping to put his love of repetition to good use someday.

Howard: My arm is feeling numb. *Howard rubs his right arm*
Bernadette: That's the wrong arm for a heart-attack, doofus.
*Howard switches to his left arm*

Amy: It's actually steamier than it looks. Sheldon's looking up the phallic symbolism of root vegetables in renaissance paintings.
Sheldon: Oh no, I got bored of that. I'm just browsing cuticle scissors on Amazon.