9.1 and 9.2 Glycolysis Intro and Simple Sugars

Question 1

what is the overall goal of glycolysis?

Answer 1

splits 2 glucose into 2 pyruvates

Question 2

what is the glucose molecular formula?

Answer 2

C6H12O6

Question 3

what is the most abundant monosaccharide in nature?

Answer 3

glucose

Question 4

describe glycolysis in terms on influx and outflux

Answer 4

glucose influx, pyruvate outflux

Question 5

how can multiple reactions be coupled together?

Answer 5

via common intermediates

Question 6

what can coupled reactions do to an energetically unfavorable process?

Answer 6

make it favorable (lower delta G)

Question 7

what are the 2 kinds of simple sugars?

Answer 7

1. monosaccharides
2. disaccharides

Question 8

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

Answer 8

in equilibirum with each other

Question 9

what are the 3 ways to draw a simple sugar?

Answer 9

1. fischer projection
2. haworth projection
3. chair projection

Question 10

what is the sweet taste of sugar due to?

Answer 10

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

Question 11

what determines sweetness?

Answer 11

affinity of the sugar to the receptor protein

Question 12

describe how kd is related to sweetness

Answer 12

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

Question 13

describe aldoses

Answer 13

have aldehyde at C1

Question 14

describe ketoses

Answer 14

have ketone at C2

Question 15

what are 2 types of monosaccharides?

Answer 15

1. aldoses
2. ketoses

Question 16

describe the middle carbons of monosaccharides

Answer 16

chiral with OH and H attached

Question 17

what is on the end of every monosaccharide?

Answer 17

CH2OH

Question 18

how are monosaccharides characterized? give 4 examples

Answer 18

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

Question 19

what are enantiomers?

Answer 19

mirror images that are not superimposable, optical isomers

Question 20

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

Answer 20

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

Question 21

describe the chiral centers in enantiomers

Answer 21

all chiral centers differ

Question 22

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

Answer 22

the chiral carbon furthest away from the carbonyl

Question 23

what are sugar epimers?

Answer 23

sugars that differ by the stereochemistry of one chiral carbon

Question 24

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

Answer 24

as cyclic structures

Question 25

how do rings of 5-7 carbon monosaccharides for?

Answer 25

spontaneously by linking carbonyl with hydroxyl

Question 26

what does the hexose aldose form when it cyclizes?

Answer 26

hemiacetals

Question 27

what is a hemiacetal?

Answer 27

aldehyde + alcohol

Question 28

what is a 6-membered ring called?

Answer 28

pyranose

Question 29

what do ketoses form when they cyclize?

Answer 29

hemiketals

Question 30

what is a hemiketal?

Answer 30

ketone + alcohol

Question 31

what is a 5-membered ring called?

Answer 31

furanose

Question 32

what is the anomeric carbon of a sugar?

Answer 32

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

Question 33

describe sugar anomers

Answer 33

only differ by anomeric carbon

Question 34

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

Answer 34

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

Question 35

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

Answer 35

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

Question 36

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

Answer 36

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

Question 37

what do reducing sugars have?

Answer 37

at least on reducing end

Question 38

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

Answer 38

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

Question 39

what is used as a reductant in reducing sugars?

Answer 39

aldehyde, or ketone converted to aldehyde

Question 40

what form is required for reduction?

Answer 40

open chain form

Question 41

describe nonreducing sugars (3)

Answer 41

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

Question 42

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

Answer 42

a reducing sugar

Question 43

what do reducing ends have?

Answer 43

free anomeric carbon

Question 44

what do nonreducing ends have?

Answer 44

anomeric carbon in a glycosidic bond

Question 45

what are the 6 steps for naming disaccharides?

Answer 45

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

Question 46

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

Answer 46

GO DRAW THEM NOW!!