AP BIOLOGY- generic molecular formulas?

Question

i need to know the functional group and a type of molecule or cell that it is commonly found in.

1. x-ch3 (x-ch subscript 3):

2. x-coh:

3. x-co-x:

4. x-h2-po4 (x-h subscript 2-po subscript 4):

thanks

Answer 1

1. -methyl

2. aldehyde

3. ketone

4. phosphate?