Biochemistry 4: Carbohydrate Structure and Function Flashcards

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1
Q

aldoses

A

carbohydrates that contain an aldehyde group as their most oxidized functional groups

carbonyl carbon can participate in glycosidic linkages

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2
Q

ketoses

A

carbohydrates that contain a ketone group as their most oxidized functional groups

carbonyl carbon can participate in glycosidic linkages

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3
Q

what sugar is this?

A

glyceraldehyde

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4
Q

what sugar is this?

A

dihydroxyacetone

the simplest ketose

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5
Q

what sugar is this?

A

D-glucose

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6
Q

what sugar is this?

A

D-fructose

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7
Q

what sugar is this?

A

D-galactose

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8
Q

what sugar is this?

A

D-mannose

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9
Q

sugars with the highest-numbered chiral carbon with the -OH group on the right

A

D-sugars

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10
Q

sugars with the highest-numbered chiral carbon with the -OH group on the left

A

L-sugars

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11
Q

enantiomers

A

D- and L-forms of the same sugar

nonsuperimposable compounds in which every chiral center is the opposite from each other

mirror images

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12
Q

diastereomers

A

nonsuperimposable configurations of molecules with similar connectivity

differ in at least one (but not all) chiral carbons

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13
Q

epimers

A

a subtype of diastereomers

differ at exactly one chiral carbon

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14
Q

anomers

A

a subtype of diastereomers

differ at the anomeric carbon

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15
Q

anomeric carbon

A

the new chiral center formed in the ring closure

in the straight-chain form, was the carbon containing the carbonyl group

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16
Q

beta-anomer

A

glucose anomer

-OH group of C-1 is equatorial and up

cis to CH2OH

17
Q

alpha-anomer

A

glucose anomer

-OH group of C-1 is axial and down

trans to CH2OH

18
Q

mutarotation

A

the shifting of cyclic compounds from one anomeric form to another with the straight-chain form as an intermediate

occurs in water

19
Q

fischer projection –?–> haworth projection

A

hemiacetal formation

20
Q

aldoses can be oxidized to ___ and reduced to ___

what about oxidation in ring form?

A

oxidized to aldonic acids

reduced to alditols (alcohols)

in cyclic form will be oxidized to lactones (cyclic ester with carbonyl at anomeric carbon)

21
Q

reducing sugars

A

sugars that are able to be oxidized

have hemiacetal rings

22
Q

Tollen’s reagent

[Ag(NH3)2]+

A

detects reducing sugars

when aldehydes are present, reagent will produce a silvery mirror

23
Q

Benedict’s reagent

A

detects reducing sugars

oxidizes aldehyde group when present, creating a red precipitate of Cu2O

24
Q

tautomerization

A

the rearrangement of bonds in a compound, usually by moving a H to form a double bond

25
Q

enol

A

compound with double bond and alcohol group

ketones can’t be oxidized directly into COOH

instead tautomerizes to form aldose (keto-enol shifts), and reacts with Tollen’s or Benedicts reagents to form COOH

26
Q

deoxy sugar

A

reduced sugar with -H replacing an -OH group

(being reduced)

27
Q

hemiacetal + alcohol –> ______

A

acetal

anomeric OH interacts with an alkoxy group (CH chain bonded to alcohol) to create a glycosidic bond

28
Q

pyranose

A

saccharides that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom

29
Q

furanose

A

saccharides that have a chemical structure that includes a five-membered ring consisting of four carbon atoms and one oxygen atom

30
Q

sucrose

A

glucose-alpha-1,2-fructose

31
Q

lactose

A

galactose-beta-1,4-glucose

32
Q

maltose

A

glucose-alpha-1,4-glucose

33
Q

what sugar is this?

A

glucose

34
Q

cellulose

A

the main structural component for plant cell walls

beta-1,4 D-glucose glycosidic bonds

source of fiber for humans because we can’t digest the beta bonds

35
Q

starch

A

main energy storage form in plants

amylose - alpha-1,4 D-glucose glycosidic bonds

amylopectin - alpha-1,4 and alpha-1,6 D-glucose glycosidic bonds

amylopectin branches

36
Q

beta-amylase

A

enzyme that cleaves amylose at the nonreducing end (at the acetal)

37
Q

alpha-amylase

A

cleaves amylose randomly along the chain to yield short chains of maltose and glucose

38
Q

glycogen

A

main energy storage form for animals

alpha-1,4 and alpha-1,6 glucose glycosidic bonds

has more 1,6 linkages, creating more branches

more energy-efficient, allows more degrative enzymes to break it down