B10 Stereochemistry in biomolecules

What is the difference between D and L isomers of the carbohydrates

• D isomers have the hydroxyl group on the left side

• The difference lies in the orientation of hydroxyl group on the chiral carbon furthest from carboxyl group

• L isomers have the hydroxyl group on the left side

• The difference lies in the orientation of the hydroxyl group on the chiral carbon furthest from carbonyl group

D-Ribose and L-Ribose are

• Enantiomers

• Diastereomers

• non-superimposable

• mirror image

These two carbohydrates molecules are isomers

• True

• False

Epimers are diastereomers that differ in the configuration of how many chiral carbon

What is the characteristics of cellulose

• A polymer of B-glucose

• Monomers bind by 1,4 glycosidic links

• Branched structure

• Low mechanical strength

Structure shown is

• B-glucose

• a-glucose

• a-fructose

• B-fructose

What form of Vitamin A involves in vision mechanism

• Retinol

• Retinoic acid

• Retinal

Characteristics of Rhodopsin

• Made up of trans-retinal and opsin protein

• Made up of cis-retinal and opsin protein

• Light-sensitive pigment

• Can be broken down and regenerate

Conversion of cis-retinal to trans-retinal involves

• Lights

• Enzymes

• Generation of electrical signals to be sent to the brain

• Photoisomerization

What happen if we are lack of Vitamin A

• Maintained rhodopsin amount

• Healthy eyes

• Reduced rhodopsin amount

• Night blindness