biochem chapter 7: carbohydrates

what is the difference between aldoses and ketoses?

aldose: first carbon has the c=o

ketose: second carbon has the c=o

how do ‘D’ and ‘L’ designations of carbohydrates arise? which of these two forms is predominantly found in nature?

• in Fischer projections D=OH on the right and L= OH to the left of the highest # carbon

• configuration of the highest-numbered asymmetric center

• D sugars DOMINATE in nature

what are epimers?

diastereomers that only differ at 1 chiral center

what is the difference between hemiacetal and hemiketal?

hemiacetal: one hydrogen, one r group, and one oh

hemiketal: two r groups, one oh

anomeric carbon

the chiral (formally chiral) carbon created due to sugar cyclization

what are the alpha and beta designations of pyranoses?

alpha: points down, and trans to C6

beta: points up, cis to C6

what is the difference between pyranoses and furanoses?

pyranose: 6 membered version

furanose: 5 membered version

describe the formation of furanoses