How come when you plug your nose you can't taste anything? Does it block out your taste buds when you do that?

No it does not block out your taste buds, however you are used to tasting along with smell. So when you plug your nose your experience is drastically altered because you are not smelling along with tasting. You are so accustomed to doing both simultaneously that when you plug your nose and prevent smelling it changes the way you perceive the taste, but your taste buds are still doing their job.

In addition, taste buds recognize four basic kinds of tastes: sweet, salty, sour, and bitter. (There's some discussion of a fifth -- spicy.) The salty/sweet taste buds are located near the front of your tongue; the sour taste buds line the sides of your tongue; and the bitter taste buds are found at the very back of your tongue.

Even with a plugged-up nose, you should be able to experience the basic sensations caused by something that's sweet or sour or bitter or salty (or spicy).

In addition, taste buds recognize four basic kinds of tastes: sweet, salty, sour, and bitter. (There's some discussion of a fifth -- spicy.) The salty/sweet taste buds are located near the front of your tongue; the sour taste buds line the sides of your tongue; and the bitter taste buds are found at the very back of your tongue.

Even with a plugged-up nose, you should be able to experience the basic sensations caused by something that's sweet or sour or bitter or salty (or spicy).
I am going to have to pay more attention. I love that:D