To represent D-Fructose, D-Glucose, and D-Galactose in Fischer projection, it’s essential to understand that these sugars are aldohexoses (for glucose and galactose) and a ketohexose (for fructose). Fischer projections allow us to visualize the stereochemistry of these sugars in two dimensions.
D-Glucose Fischer Projection:
D-Glucose is an aldohexose with the following Fischer projection:
CHO
|
H - C - OH
|
HO - C - H
|
H - C - H
|
H - C - OH
|
CH2OH
D-Galactose Fischer Projection:
D-Galactose is also an aldohexose, and its structure differs from glucose at the C-4 carbon:
CHO
|
H - C - OH
|
HO - C - H
|
H - C - OH
|
H - C - H
|
CH2OH
D-Fructose Fischer Projection:
D-Fructose is distinct as a ketohexose, and its Fischer projection looks like this:
CH2OH
|
C = O
|
H - C - OH
|
H - C - OH
|
H - C - H
In each of these projections, the vertical lines represent bonds that are going back into the plane of the paper, while the horizontal lines represent bonds that are coming forward. This format helps in identifying the stereochemical configuration of each sugar. Each of these sugars plays a crucial role in metabolism and energy production in living organisms.