Biochem Exam 3- Carbs

Front 1

ratio of C to H to O of carbohydrate

Back 1

Cn(H2O)n
carbohydrate stands for "hydrated carbons"
1C:2H:1O

Front 2

how to number carbons on a carbohydrate

Back 2

start at the carbon at the end closest to, or of the carbonyl group

Front 3

composition of human body (in terms of carbs, fat, etc)

Back 3

<2% dry weight carbs
41% fat
41% protein
15% inorganic

Front 4

intake of carbohydrates is much greater than the composition in the human body. where does it all go (2)?

Back 4

to make energy (ATP) or convert to fat

Front 5

roles of carbohydrates (5)

Back 5

1) ATP production
2) energy storage
3) precursor to lipids
4) informational molecules
5) structural molecules

Front 6

how to plants/animals store carbs as energy?

Back 6

animals: glycogen
plants: starch

Front 7

how do carbs work as informational molecules? (2)

Back 7

destination tags on proteins
identity tags on cells (blood type)

Front 8

simple sugars

Back 8

contain just C, O, H

Front 9

monosaccharide derivatives

Back 9

may contain other types of atoms (S,N)

Front 10

disaccharides

Back 10

2 sugar units linked covalently

Front 11

oligosaccharides

Back 11

3-10 units

Front 12

properties of monosaccharides (3)

Back 12

1) all have at least 1 OH group
2) all have a carbon chain (needs to be at least 3 total C's long)
3) all have aldehyde or keto group (carbonyl group between 2 carbons)

Front 13

isomers

Back 13

have same molecular formula

Front 14

aldo-

Back 14

sugar with aldehyde group

Front 15

keto-

Back 15

sugar with keto group

Front 16

3C, 4C, 5C, 6C chain

Back 16

triose, tetrose, pentose, hexose

Front 17

stereoisomers

Back 17

same atomic connectivities, but different orientations around 1 or more chiral centers

Front 18

chiral centers

Back 18

centers around which all 4 groups are different (meaning the whole R chain, not just the molecule directly after it)

Front 19

how to determine # of stereoisomers in a linear monosaccharide?

Back 19

multiple the number of possible arrangements per chiral center

Front 20

In a fischer projection, all D sugars have...

Back 20

OH on the right side of chiral carbon farthest from carbonyl C

Front 21

In a fischer projection, all L sugars have...

Back 21

OH on the left side of chiral carbon farthest from the carbonyl C

Front 22

light rotation of a monosaccharide based on D/L configurations

Back 22

cannot tell based on D/L designation (probably for same reason as AA, because there are multiple chiral centers)

Front 23

what do the D and L designations of monosaccharides refer to?

Back 23

structural relationship to arbitrary standard, D/L glyceraldehyde

Front 24

most naturally occurring sugars are...(in terms of D/L)

Back 24

D isomers

Front 25

epimer

Back 25

stereoisomers that differe in the arrangement of groups at just ONE chiral center (can name based on which chiral carbon it occurs on e.g. 4'-epimer)

Front 26

interconversion between D and L isomers

Back 26

must flip the whole molecule, not just around the farthest chiral carbon

Front 27

enantiomers

Back 27

stereoisomers that differ in arrangements of groups at ALL chiral centers (D/L configuration)

Front 28

which sugars most commonly cyclize? and what is the terminology for what they form?

Back 28

pentoses/hexoses
form cyclic hemiacetals (aldehyde combines with OH) or cyclic hemiketals (will have an extra R-group at the anomeric carbon)

Front 29

hemiacetals and hemiketals form from...

Back 29

OH + aldehyde: O of an OH group attacks partial positive C of aldehyde group causing double bond to shift one pair of electrons to the O of aldehyde. O with extra electrons receives H from the attacking OH.
OH + ketone

Front 30

anomeric carbon in ring structure

Back 30

the original aldo or keto carbon

Front 31

anomers

Back 31

stereoisomers that differ only in arrangement of groups around anomeric carbon

Front 32

pyranose

Back 32

term for six membered rings consisting of 5 carbons and one O.

Front 33

alpha designation

Back 33

indicates that OH group on anomeric carbon is in the SAME configuration as the ring oxygen (relative to end carbon).

Front 34

beta designation

Back 34

indicates anomeric OH and ring O are in opposite configruation

Front 35

fischer projection conversion from haworth steps (2)

Back 35

1) put anomeric carbon at top of linear carbon chain
2) OH group that is "down" on haworth = on the right of carbon in Fischer

Front 36

furanose

Back 36

term for 5 membered ring with 4 carbons and an O

Front 37

mutarotation

Back 37

converstion between different epimeric forms in solution

Front 38

how can you tell which anomer is more abundant in an equilibrium mixture? what does the abundance imply?

Back 38

look at degrees of rotated light (to one direction) of the two pure forms and see to which associated value the equilbrium light rotation is closer to. abundance implies stability.

Front 39

what is the most likely cause of instability in cyclic monosaccharides?

Back 39

steric interference (between OH groups, or whatever)

Front 40

reducing sugars

Back 40

sugars and sugar derivatives that have free anomeric OH groups.
called "reducing" because they can reduce metal ions such as Cu++ or Fe3+

Front 41

old assay for serum or urninary glucose was based on...

Back 41

ability of liquid to reduce Cu+2 to Cu2O (cupric oxide) - a red precipitate

Front 42

old serum/urine assay for glucose equation

Back 42

a-D-glucose/b-D-glucose&lt;<-->linear D-Glucose + 2Cu++ + 5OH- -->D-gluconate + cupric oxide + 3H2O

Front 43

"-ide" suffix e.g. glucopyranoside and it's effect on mutarotation

Back 43

indicates that anomeric hydroxy group is not free. cannot mutarotate?

Front 44

issue with old reducing sugar assay test

Back 44

not specific enough for beta-D-glucopyranose (an anomer of glucose)

Front 45

modern assay for glucose rxn contains...(5)

Back 45

urine or blood sample
glucose oxidase
a dye capable of reducing peroxide
peroxidase
mutarotase

Front 46

glucose oxidase

Back 46

enzyme very specific for b-D-glucopyranose that release peroxide in the rxn

Front 47

peroxidase

Back 47

enzyme that catalyzes peroxide reduction

Front 48

mutarotase

Back 48

enzyme catalyzing mutarotation of a-D-glucopyranose, linear glucose, a/b-D-glucofuranose to b-D-glucopyranose

Front 49

D-gluconolactone

Back 49

what is produced after glucose oxidase oxidizes b-D-glucopyranose

Front 50

purpose of the dye in glucose assay

Back 50

oxidized dye (after reducing peroxidase) should turn a different color, which is then measured via spectrophotometry

Front 51

what are some reactions that the anomeric OH group of sugar units can partake in?

Back 51

react with alcohol groups of other molecules (specifically other monosaccharides) results in formation of O-glycosides and release H2O

Front 52

is the formation of O-glycosides spontaneous?

Back 52

not under standard state conditions, but can proceed in vivo if coupled with NTPs

Front 53

galactose in relationship to glucose

Back 53

is an epimer around the 4th carbon (4-epimer)

Front 54

naming convention of O-glycoside bonds

Back 54

glycosidic bond is the generic term.
specifically, refer to the sugar that is doing the anomeric bonding? (galactosidic, etc)

Front 55

steps of naming convention of O-glycosidic compound

Back 55

start from monosaccharide linked with anomeric carbon.
Write the name.
Determine whether it is alpha or beta, then write the number of the anomeric carbon with an arrow pointing forward.
Then write the number of the bound carbon on the second monosaccharide. if the second carbon is also anomeric then make the arrow go both ways.
Write the name of the second monosaccharide.

Front 56

monosaccharide functions (2)

Back 56

energy (ATP) production
building blocks of more complex carbs

Front 57

disaccharide functions (2)

Back 57

transport- transport of sugar throughout the system (e.g. trehalose in insects, lactose in mother-->baby)
intermediates in the metabolism of more complex carbohydrates (if you synth or degrade carbs, usually it will become a disaccharide at some point)

Front 58

oligosaccharide function

Back 58

information- can use a few monosaccharide "words" to make many oligosaccharide "sentences"

Front 59

polysaccharide functions (2)

Back 59

storage- glycogen/starch
structure (cellulose, glycosaminoglycans)

Front 60

how do carbohydrates work as structural molecules?

Back 60

plants: cellulose
animal (more minor role): CT proteins embedded in carbs called glycosaminoglycans

Front 61

monosaccharide (?) transporters in plants and animals

Back 61

plants: sucrose transports sugars in plants
insects: trehalose
animals: lactose (milk sugar) to infants in boob milk

Front 62

how to count how many disaccharides you can make from 2 glucoses in a glycosidic bond

Back 62

1 anomeric carbon in alpha state can link to another alpha-monosaccharide on carbons 2,3,4,5... x 4 because you can link alpha-->beta 2,3,4,5 or beta-->beta, etc.
then add the combinations if the anomeric carbons were bound to each other (a1--1a, b1--1b, a1--1b)

Front 63

3 letter abbreviations for
1) fructose
2) ribose
3) glucose
4) galactose
5) mannose

Back 63

fru, rib, glc, gal, man (also know structures)

Front 64

how to tell alpha or beta? on a fischer projection

Back 64

if O bond is to the right, it's hfgwehgwhgwg
left = L

Front 65

how to tell alpha or beta on a fischer projection

Back 65

if anomeric (top carbon) oh and O are on the same side = alpha
different side = beta