Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOC 4331 > Ch 7.1-7.2Carbohydrates > Flashcards

Ch 7.1-7.2Carbohydrates Flashcards

1
Q

What is the most abundant biomolecule in the known universe?

A

D-Glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the general formula for carbohydrates?

A

(CH2O)n, where n > 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Some roles of carbohydrates in cells

A

precursors for almost all other biomolecules, used to produce energy, linked to other molecules (ex: glycolipid, glycoprotein)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe the classification and naming of carbohydrates

A

1) whether it is an aldehyde (aldose, aldo-) (more common in carbohydrates ) or a ketone (ketose, keto-)
2) number of carbon atoms:

3 (triose), 4 (tetrose), 5 (pentose), 6 (hexose), 7 (heptose)

ex: aldohexose or ketopentose
4) A monosaccharide is given D configuration if the -OH group of the penultimate carbon (that forms the hemiketal or hemiacetal) is on the same side as D-Glyceraldehyde.
5) A cyclic monosaccharide is given the α (alpha) designation if the -OH group of the anomeric carbon is on the same side as the oxygen atom on the highest numbered asymmetric carbon in the ring with a hydroxyl group (one below the penultimate carbon that forms the hemiketal or hemiacetal), β (beta) if it is on the opposite side.

.

Note: Designation of D or L relates the configuration of a given molecule and does not specify the sign (+ or -) of rotation of plane-polarized light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the classification of D-Glucose?

A

aldohexose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the classification of D-Fructose?

A

ketohexose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the cutoff points for monosaccharides, oligosaccharides and polysaccharides?

A

Monosaccharide:

1 residue

Oligosaccharides:

2-10 residues

disaccharide - 2

trisaccharide - 3

tetrasaccharide - 4

Polysaccharide:

many residues (up to thousands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

monosaccharide

A

a sugar with one residue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

oligosaccharide

A

a sugar with 2-10 residues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

polysaccharide

A

a sugar with more than 10 residues (up to thousands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

enantiomer

A

stereoisomers that are a mirror images of each other.

ex: D-Glyceraldehyde and L-Glyceraldehyde

enantiomers rotate polarised light in opposite directions and DO NOT interact with the same binding sites on enzymes or proteins (lock-and-key hypothesis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

epimer

A

stereoisomers (specifically diastereomers) that differ in stereochemistry at only one chiral carbon, aside from

ex: D-Erythrose and D-Threose are 2-epimers of each other.
ex: D-Glucose and D-Galactose are 4-epimers of each other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the numbering convention of carbohydrates?

A

For aldoses, C1 is the most oxidised carbon (the carbonyl carbon).

For ketoses, the carbonyl carbon is C2.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the simplest chiral carbohydrate?

A

Glyceraldehyde. Carbohydrates have three or more carbons: the ketotriose (dihydroxyacetone) is not chiral, but the aldotriose (glyceraldehyde) is.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is a cyclic sugar with a five membered ring called?

A

furanose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is a cyclic sugar with a six membered ring called?

A

pyranose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

pyran

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

furan

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

pyranose

A

pyranose: a sugar with a six membered ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

furanose

A

furanose: a sugar with a five membered ring

21
Q

hemiacetal

A

covalent bond between a hydroxyl group and an aldehyde

22
Q

hemiketal

A

covalent bond between a hydroxyl group and a ketone

23
Q

when a carbohydrate cyclises, which oxygen is responsible for the intracyclic oxygen?

A

the oxygen from the alcohol functional group of the hemiketal/hemiacetyl

24
Q

when converting from a linear Fisher projection to a cyclised Haworth projection, what is the convention?

A

The intracyclic oxygen is at the top or upper-right of the ring in the Haworth projection. All subsituents on the left in the Fisher projection point up in the Haworth projection, conversely all substituents on the right point down. If the carbonyl oxygen (that is now a hydroxyl) points the opposite direction of the -OH group in the highest numbered chiral carbon with a hydroxyl, the new cyclic structure is said to be β (beta). If it points the same direction as that group it is said to be α (alpha).

25
Q

When a cyclised carbohydrate interconverts from alpha to beta form it is called what?

A

mutarotation

26
Q

what is the predominate anomer of glucose?

A

β (beta) anomer, due to steric hinderence. Most bulky groups can be placed on the equatorial positions of the ring in chair conformation using this mutarotation.

27
Q

anomer

A

Two stereoisomers that differ only in their configuration about the anomeric carbon atom (the central carbon of an acetal or a hemiacetal)

28
Q

describe the energy diagram of a pyranose in its various forms

A

45.2kJ/mol (10.8kcal/mol) from chair to half-chair

23kJ/mol (5.5kcal/mol) from chair to twist-boat

30kJ/mol (72kcal/mol) from chair to boat

29
Q
A

D-Ribose

30
Q
A

D-Glucose

31
Q
A

D-Galactose

32
Q

What is the structure of:

D-Ribose

A

D-Ribose

33
Q

What is the structure of:

D-Glucose

A

D-Glucose

34
Q

What is the structure of:

D-Galactose

A

D-Galactose

35
Q

where is the intracyclic oxygen in the two chair forms of a pyranose?

A
36
Q

describe the two chair forms of β-D-Glucopyranose

A
37
Q

what is the difference between fructose and glucose?

A

fructose is the ketose form of glucose, which is an aldose (the carbonyl is on C2 in fructose and C1 in glucose)

38
Q
A

D-Fructose

39
Q

What is the structure of:

D-Fructose

A
40
Q
A

glycerol

41
Q

What is the structure of:

glycerol

A
42
Q
A

2-Deoxy-β-D-ribofuranose

43
Q

What is the structure of:

2-Deoxy-β-D-ribofuranose

A
44
Q
A

N-acetyl-D-glucosamine

45
Q

What is the structure of:

N-acetyl-D-glucosamine

A
46
Q

what is the ketotriose called?

A

dihydroxyacetone

47
Q

What is the aldotriose called?

A

glyceraldehyde (chiral!)

48
Q

What is the difference between the ketotriose and the aldotriose besides the location of the carbonyl?

A

The ketotriose is achiral while the aldotriose is chiral

BIOC 4331 (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions