Biochem Chapter 8

Question 1

4 roles of carbohydrates

Answer 1

energy storage
structural framework
structural elements
subunits of glycoproteins and glycolipids

Question 2

D sugar means

Answer 2

OH on right, rotates light +, CW

Question 3

L sugar means

Answer 3

OH on left, rotates light -, CCW

Question 4

glucose is an ____

Answer 4

aldose, means it terminates with H-C=O

Question 5

fructose is a ____

Answer 5

ketose, means terminates with CH2OH-C=O

Question 6

ketoses are _______, while aldoses are ____

Answer 6

non-reducing, reducing

Question 7

pyran

Answer 7

6 member ring

Question 8

furan

Answer 8

5 member ring

Question 9

mutarotation of D-Glucose

Answer 9

alpha-D-Glucopyranose where OH is down 33%

beta-D-Glucopyranose where OH is up 66% bc slightly more stable

Question 10

glycosidic bond

Answer 10

bond to an anomeric carbon

Question 11

is the 5 or 6 member ring of fructose more stable

Answer 11

5

Question 12

all sugars have at least ___ chiral carbon

Answer 12

1

Question 13

enantiomers

Answer 13

exact mirror images at every chiral carbon

Question 14

diastereomers

Answer 14

optical isomers that are not mirror images, more than 1 chiral carbon

Question 15

epimer

Answer 15

closest diastereomers, differ at only 1 carbon (D and L configuration)

Question 16

should large groups be equatorial or axial

Answer 16

equatorial

Question 17

1* OH gets oxidized to ____ then ____

Answer 17

aldehyde then -COOH

Question 18

2* OH gets oxidized to ____ then ___

Answer 18

ketone then NOTHING

Question 19

the oxidation of a cyclic hemiacetal form gives a ____

Answer 19

lactone

Question 20

alcohol sugars

Answer 20

aldehyde is reduced to an alcohol

Question 21

amino sugars

Answer 21

AKA sialic acids, found in glycoproteins, glycolipids and bacterial cell walls

Question 22

sucrose

Answer 22

1 glucose + 1 fructose
alpha-1,2, down
NONREDUCING
found in sugar cane and sugar beets

Question 23

lactose

Answer 23

1 galactose + 1 glucose
beta-1,4, up
found in milk

Question 24

maltose

Answer 24

2 glucose
alpha-1,4, down
found in beer from breakdown of starch

Question 25

anionic sugars are found in

Answer 25

cartilage, skin, proteoglycans

highly polar because they are charged

Question 26

starch or amylose

Answer 26

energy storage for plants, alpha-1,4

Question 27

cellulose

Answer 27

structural role in plants, beta-1,4

is a phenolic polymer, has tyrosine

Question 28

glycogen

Answer 28

energy storage for animals, alpha-1,4

Question 29

dextran

Answer 29

energy storage for bacteria and yeast

alpha-1,6

Question 30

chitin

Answer 30

crab shells, beta-1,4 bonds btwn chains of N-acetylglucosamines

Question 31

glycosaminoglycans

Answer 31

polymers of disaccharides, anionic carboxyl or sulfate, in cartilage and extracellular matrix, slippery, flexible, found in egg whites and mucous

Question 32

most common polysaccharide on earth

Answer 32

cellulose

Question 33

why is cellulose rigid

Answer 33

network of H-bonds between sugars and layers

Question 34

proteoglycan

Answer 34

“protein and sugar”
very anionic
holds lots of water

Question 35

lysozyme

Answer 35

cuts between the N-acetylglucosamine and N-acetylmuramic acid (2 alternating sugars) of bacterial cell wall, mostly affects gram positive, protease resistant bc of D-amino acids which prevent proteolysis

Question 36

penicillin

Answer 36

has beta-lactam ring that inhibits enzyme that makes the pentaglycine bridges of bacteria cell walls

Question 37

N-linked sugars

Answer 37

to Asn in sequence with Asn-X-Ser/Thr

Question 38

O-linked sugars

Answer 38

directly to Ser to Thr