9.1 and 9.2 Glycolysis Intro and Simple Sugars Flashcards

1
Q

what is the overall goal of glycolysis?

A

splits 2 glucose into 2 pyruvates

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2
Q

what is the glucose molecular formula?

A

C6H12O6

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3
Q

what is the most abundant monosaccharide in nature?

A

glucose

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4
Q

describe glycolysis in terms on influx and outflux

A

glucose influx, pyruvate outflux

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5
Q

how can multiple reactions be coupled together?

A

via common intermediates

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6
Q

what can coupled reactions do to an energetically unfavorable process?

A

make it favorable (lower delta G)

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7
Q

what are the 2 kinds of simple sugars?

A
  1. monosaccharides
  2. disaccharides
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8
Q

how do open chain and ring forms of simple sugars exist?

A

in equilibirum with each other

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9
Q

what are the 3 ways to draw a simple sugar?

A
  1. fischer projection
  2. haworth projection
  3. chair projection
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10
Q

what is the sweet taste of sugar due to?

A

sugars binding to G protein coupled receptors on the tongue that leads to neuronal signals in the brain

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11
Q

what determines sweetness?

A

affinity of the sugar to the receptor protein

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12
Q

describe how kd is related to sweetness

A

sweeter sugars bind receptors better, so the lower the Kd, the sqeeter the sugar

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13
Q

describe aldoses

A

have aldehyde at C1

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14
Q

describe ketoses

A

have ketone at C2

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15
Q

what are 2 types of monosaccharides?

A
  1. aldoses
  2. ketoses
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16
Q

describe the middle carbons of monosaccharides

A

chiral with OH and H attached

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17
Q

what is on the end of every monosaccharide?

A

CH2OH

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18
Q

how are monosaccharides characterized? give 4 examples

A

by number of carbons
triose: 3 Cs
tetrose: 4 Cs
pentose: 5 Cs
hexose: 6 Cs

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19
Q

what are enantiomers?

A

mirror images that are not superimposable, optical isomers

20
Q

how many enantiomers do chiral molecules that lack a plane of symmetry have? describe

A

2
D entantiomer (right-handed)
L enantiomer (left-handed)

21
Q

describe the chiral centers in enantiomers

A

all chiral centers differ

22
Q

what determines the enantiomeric configuration of sugars with multiple chiral carbons?

A

the chiral carbon furthest away from the carbonyl

23
Q

what are sugar epimers?

A

sugars that differ by the stereochemistry of one chiral carbon

24
Q

in what kind of structure are 5-7 carbon monosaccharides more stable?

A

as cyclic structures

25
Q

how do rings of 5-7 carbon monosaccharides for?

A

spontaneously by linking carbonyl with hydroxyl

26
Q

what does the hexose aldose form when it cyclizes?

A

hemiacetals

27
Q

what is a hemiacetal?

A

aldehyde + alcohol

28
Q

what is a 6-membered ring called?

A

pyranose

29
Q

what do ketoses form when they cyclize?

A

hemiketals

30
Q

what is a hemiketal?

A

ketone + alcohol

31
Q

what is a 5-membered ring called?

A

furanose

32
Q

what is the anomeric carbon of a sugar?

A

the carbonyl carbon (the only C attached to 2 oxygens)

33
Q

describe sugar anomers

A

only differ by anomeric carbon

34
Q

what are the 2 types of anomers? how do you tell?

A

look at the anomeric carbon
if OH is down: alpha anomer
if OH is up: beta anomer
(USUALLY)

35
Q

what is the exception to telling what type of anomer a sugar is by the anomeric carbon?

A

in a 5-membered ring, the higher priority CH2OH group will be up, so a beta anomer of a 5-membered (furanose) ring can have an OH in the down position

36
Q

how do you fill in the rest of the OH and H when going from Fischer projection to Haworth projection?

A

down right uplefting (if OH point to R in Fischer, will be down in Haworth, if point left, will be up)

37
Q

what do reducing sugars have?

A

at least on reducing end

38
Q

how do you tell if an end is the reducing end?

A

the OH on the anomeric carbon is NOT in a glycosidic bond, it’s free!

39
Q

what is used as a reductant in reducing sugars?

A

aldehyde, or ketone converted to aldehyde

40
Q

what form is required for reduction?

A

open chain form

41
Q

describe nonreducing sugars (3)

A
  1. cannot reduce oxidizing agents
  2. no free anomeric carbon
  3. anomeric carbon can not be isomerized into an aldehyde
42
Q

if a disaccharide has at least one reducing sugar, what is it?

A

a reducing sugar

43
Q

what do reducing ends have?

A

free anomeric carbon

44
Q

what do nonreducing ends have?

A

anomeric carbon in a glycosidic bond

45
Q

what are the 6 steps for naming disaccharides?

A
  1. start from nonreducing end with monosaccharide 1 (M1), and name with abbreviation as normal
  2. open parentheses and put the anomeric configuration of M1
  3. still in parentheses, write the carbon number for the glycosidic linkage in M1
  4. then write a single arrow for reducing and a double arrow for nonreducing sugard
  5. if 2nd monosacc (M2) is nonreducing, add anomeric configuration of M2
  6. list the carbon number of the glycosidic linkage in M2, close parentheses, and write the abbreviation of M2
46
Q

be able to draw glucose, galactose, and fructose in all 3 projections!!

A

GO DRAW THEM NOW!!