Question

Which one of these is not like the others? (2 pts each) In each set of 3 molecules CROSS OUT one option that does not fit and indicate the correct explanation for why it does not fit the set in the blank. For each set cross out only ONE molecule, and if the same set occurs twice choose a different molecule each time, using a different answer for each blank.

1. a) Glycogen Amylose

   Amylopectin

2. b) Chitin

   Cellulose

   Amylopectin

3. c) Chitin

   Cellulose

   Amylopectin

4. d) Triacylglycerol

   Sphingolipid

   Glycerophospholipid

5. e) Triacylglycerol

   Sphingolipid

   Glycerophospholipid

6. f) Proteoglycan

   Glycoprotein Lectin

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Explanations: (not all will be used)

1. Twohaveα1→4linkages;onehasβ1→4linkages

2. Twohaveβ1→4linkages;onehasα1→4linkages

3. Two have α1→6 linkages; one has β1→6 linkages

4. Twohaveα1→6branches,onedoesnot

5. TwodoNOThaveα1→6branches,onedoes

6. Two are made from D-glucose, one is not

7. Two are easily digestible by most animals, one is not

8. Two are used for energy storage, one is not

9. Two are made from glycerol, one is not

10. Two are made from fatty acids, one is not

11. Twoaremembranelipids,oneisnot

12. Two contain protein components, one does not

13. Two have covalently attached carbohydrates, one does not

Answer 1

a). Amylose is not like Glycogen and Amylopectin because two have α1→6 branches,one doesnot.

In glycogen and amylopectin both, glucose residue at branch point is bonded with first glucose residue of branch by α1→6 glycosidic linkage.

b). Amylopectin is different from Chitin and Cellulose because two have β1→4 linkages; one has α1→4 linkages.

Cellulose is the homopolymer of glucose, in which glucose unit is bonded with each other by β1→4 glycosidic bond and Chitin is a linear homopolymer of N-acetylglucosamine residues bonded with β1→4 glycosidic linkage. Whereas, there is α1→4 linkage in lineaar chain of amyloectin.

c). Amylopectin is different from Chitin and Cellulose because two do not have α1→6 branches,one does.

Cellulose and chitin are linear polysaccharides having β1→4 whereas, amylopectin has α1→6 glycosidic linkage at branch point.

d). Sphingolipid is not like the triacylglycerol and glycerophospholipid two are made from glycerol, one is not.

In triacylglycerol and glycerophospholipid fatty acids (3 fatty acids in triacylglycerol and 2 fatty acid in glycerophospholipid) are attached by ester linkage with glycerol while in sphingolipid fatty acid is attached by ester linkage with sphingosine.

e). Triacylglycerol is not like the sphingolipid and glycerophospholipid because two are membrane lipids, one is not.

Sphingolipid and glycerophospholipid are membrane lipids whereas, triacylglycerol is storage lipid.

f). Lectin is different from proteoglycan and glycoprotein because two have covalently attached carbohydrates, one does not.

In proteoglycans, glycosaminoglycan chains are joined covalently with sulphated protein.

In glycoprotein, one or many oligosaccharides joined covalently with protein.

Lectins are made up of proteins only, lectins bind with carbohydrate with high specificity that's why they are used in cell-cell recognition, cell adhesion and cell signalling.