Indicate the chiral carbon atoms found in the monosaccharides D-ribose and D-mannose.

First, let's write the molecular formula of D-ribose and D-mannose: D-ribose: C5H10O5 D-mannose: C6H12O6

Now, let's draw the Fischer projection of D-ribose and D-mannose, which shows the arrangement of atoms in these molecules in a 2D representation: D-ribose: ``` HO HO HO HO H | | | | | H-C- H-C- H-C- H-C- C=O | | | | | OH OH H OH H ``` D-mannose: ``` HO HO HO HO H | | | | | H-C- H-C- H-C- H-C- C=O | | | | | OH H H OH H ```

Now, let's identify the chiral carbon atoms in each molecule. We are looking for carbon atoms with four different substituents attached to them: In D-ribose: - C2 (the second carbon from the top) has the following substituents: H, OH, C1 (attached to H and OH), and C3 (also attached to H and OH). - C3 has the following substituents: H, OH, C2 (listed above), and C4 (attached to H and OH). Both C2 and C3 are chiral because they have four different substituents. In D-mannose: - C2 has the following substituents: H, OH, C1 (attached to H and OH), and C3 (attached to H and OH). - C3 (the third carbon from the top) has the following substituents: H, H, C2 (listed above), and C4 (attached to H and OH). Only C2 is chiral in D-mannose, as C3 does not have four different substituents.

Finally, let's indicate the chiral carbons in D-ribose and D-mannose: In D-ribose, the chiral carbons are C2 and C3. In D-mannose, the chiral carbon is C2.