Structure And Function: Carbohydrates

Question 1

Aldose

Answer 1

Aldehyde group on carbon 1

Fast reducing sugar

Question 2

Ketose

Answer 2

Keto group on carbon 2

Slow reducing sugar

Question 3

Glucose in urine

Answer 3

Diabetes mellitus

Question 4

Fructose in urine

Answer 4

Fructosuria & hereditary fructose intolerance (uncommon)

Question 5

Galactose in urine

Answer 5

Galactosemia

Question 6

Glyceraldehyde

Answer 6

3C aldose

Question 7

Dihydroxyacetone

Answer 7

3C ketose

Question 8

Ribose & Xylose

Answer 8

5C Aldose

Question 9

Ribulose & Xylulose

Answer 9

5C Ketose

Question 10

Glucose, Galactose, Manose

Answer 10

6C Aldose

Question 11

Fructose

Answer 11

6C Ketose

Question 12

Sedoheptulose

Answer 12

7C Ketose

Question 13

Neuraminic acid (NANA)

Answer 13

9C Aldose & Ketose

Question 14

Monosaccharide cyclization

Answer 14

Present in cyclic form in solution

Beta glucose predominant

Question 15

Epimers

Answer 15

Glucose - galactose (C-4)

Glucose - manose (C-2)

Question 16

Epimerase

Answer 16

interconvert epimers (galactose metabolism)

Question 17

Nuceloside linkate

Answer 17

Beta-N-glycosidic linkage

Question 18

Polyols (sugar alcohols)

Answer 18

Sorbitol - formed from glucose; responsible for chronic complications in diabetes mellitus; formed via aldose reductase
Galactitol formed from galactos in children with galatosemia

Polyols are dead end products of metabolism & draw water into cells

Question 19

Lactose

Answer 19

Disaccharide
Beta1-4 glycosidic linkage
Glucose and galactose
Cleaved by lactase in small intestinal mucosal cells

Question 20

Sucrose

Answer 20

Glucose + Fructose
Nonreducing sugar (aldehyde and keto groups not free)
Cleaved by intestinal sucrase

Question 21

Fructose

Answer 21

Monosaccharide
HFCS 55
Ketohexose

Question 22

Maltose

Answer 22

Disaccharide
2 glucose units
alpha1-4 glycosidic linkage
reducing sugar
formed as product of starch by amylase
cleaved to glucose by maltase

Question 23

Glycogen

Answer 23

Storage polysaccharide
In liver and muscle cells
Linear chain = alpha1-4 linkage
Branched chain = alpha1-6 linkage

Question 24

Starch

Answer 24

Dietary polysaccharide
Amylose - linear unbranched chain of glucose
Amylopectin - branched polymer of glucose
Digested by salivary and pancreatic amylase

Question 25

Glycosaminoglycans

Answer 25

Repeating disaccharides
Hyaluronic acid
Heparin
Heteropolysaccharide

Question 26

Cellulose

Answer 26

Dietary fiber
Beta1-4 linkage
Can’t be cleaved in humans

Question 27

Glycoproteins

Answer 27

O-linked: glycosylation of OH group on Ser/Thr, extracellular proteins or membrane bound, glycan groups face extracellular side
N-linked: glycosylation on Asn residue, high mannose or complex