Brainscape's Knowledge GenomeTM

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


See full index

BCM210 > Topic 8 - Carbohydrates > Flashcards

Topic 8 - Carbohydrates Flashcards

1
Q

Describe the structure and chemical reactivity of alcohol functional group

A

Is an -OH group attached to a saturated C atom. -due to -OH group, can H bond -are polar -

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

Describe the structure and chemical reactivity of the aldehyde & ketone functional groups

A

carbonyl functional group is a carbon double bonded to an oxygen
-can undergo oxidation reactions

-can undergo keto-enol tautomerism. This refers to the equilibrium between the two possible tautomers. The interconversion of the two forms involves the movement of a proton and the shifting of bonding electrons. This equilibrium affords the compounds more reactivity

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

Describe the structure and function of ether functional group

A
  • inability to form H bonds w/ each other
  • slightly polar
  • subject to reacting w/ strong acids due to two lone pairs of electrons on O atom
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the structure and chemical reactivity of the anhydride functional group

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

List the major functions of Carbohydrates

A

Energy storage e.g. starch (plants) glycogen (animals)

Structural e.g. cellulose, chitin

Extenders of protein function e.g. when combined w/ proteins, CHD increase H2O binding capacity

**Informational molecules **e.g. bar codes on proteins, secind messengers in signal transduction

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

Define Carbohydrates and give their formula

A

A CHD is a compound w/ 3 or more C atoms which as an aldehyde or keto functional group & two or more hydroxyl groups

Cn(H2O)n

  • Produced from CO2 and H2O during photosynthesis in plants
  • Can be covalently linked w/ proteins to form glycoproteins & proteoglycans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a mono/di/trisaccharide?

A

Mono: A simple CHD; consists of only one sugar unit. Cannot be hydrolysed to smaller CHD molecule

Di: complex CHD; 2 sugar units

Tri: complex CHD; 3 sugar units

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

What is a oligosaccharide?

A

A complex CHD

consists or two or more sugar units

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

What is a polysaccharide?

A

consists of many sugar units (more than 20); it is a CHD polymer (complex)

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

(monosaccharides)

How many carbons does a….
triose have?

tetrose?

pentose?

hexose?

A

triose =3

tetrose =4

pentose =5

hexose =6

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

What two groups can monosaccharides be divided into?

A

aldehydes and ketones

  • name beginning w/ “aldo” =terminal carbonyl group is aldehyde
  • name beginning w/ “keto” =NON-terminal carbonyl group is ketone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

(monosaccharides)

Trioses are either aldo trioses or ketotrioses and so on up to aldohexoses and ketohexoses

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

What are stereoisomers?

A

are different compounds that have the same structure, but differ only in the arrangement of the atoms in 3D space.

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

All monosaccharides, except dihydroxyacetone, contain at least 1 chiral C and therefore occur as stereoisomers.
T or F?

A

True

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

Molecules w/ one chiral C have 1 type of stereoisomer. Name and describe this stereoisomer.

A

Enantiomers (pair)

-is one of two stereoisomers that are mirror images of each other that are “non-superposable”

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

How do we know if a monosaccharide is a D series or L series

A
  • A monosaccharide is a member of the D-series, if the hydroxyl group on the chiral carbon farthest from carbon 1 is on the right.
  • A monosaccharide is a member of the L-series, if the hydroxyl group on the chiral carbon farthest from carbon 1 is on the left.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are diastereomers?

A

Any pair of stereoisomers that are NOT enantiomers (not mirror images) and differ in 1 or more chiral centres

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

What are epimers?

A

Non mirror image isomers that differ only in the configuration around one chiral atom

**not epimers if they differ by more than one chiral atom

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

Stereoisomer nomenclatural summary

A
20
Q

What is the formula used to determine the number of isomers of aldo and keto sugar families?

A

2n
where n is the number of chiral centres

e.g. Aldotetroses (with 4C) have two chiral centres.
Thus 22 equals 4 stereoisomers.

21
Q

What kind of pentose is Ribose?

A

aldo-pentose

22
Q

What kind of hexose is glucose?

A

aldo-hexose

23
Q

What kind of hexose is fructose?

A

keto-hexose of glucose

24
Q

Please read over practice (clicker) Q’s in lecture
:)

A

do it!!!!!!!!!

25
Q

Monosaccharides with a 5+ C atoms occur predominantly as what?

How is this formed?

A

cyclic structures

-formed by aldehyde or ketone groups reacts w/ a hydroxyl group along the chain, forming a covalent bond

26
Q

Describe how to ID alpha and beta forms of simple CHD’s

A

The middle step where the OH migrates down

=>this can cause rotation, so the molecule either becomes stuck as
alpha (OH below ring)
beta (OH above ring)

27
Q

What is an anomer?

A

Compounds that differ in configuration only aroun the C atom that may yield a carbonyl group (ketone or aldehyde) on rearrangement.

28
Q

Number of cyclic stereoisomers

(see answer)

A
  • Therefore, from the 16 (24) aldohexose stereoisomers, there are an additional 32 cyclic isomers
  • i.e. 16 pairs of anomers
  • Plus 16 LINEAR isomers
  • = 48 total aldohexose isomers
29
Q

What are conformers?

How do they differ from configurational isomers? (enantiomers, diastereomers, anomers)

A

Molecules w/ the same stereochemical configuration, but differ in 3D conformation

-differ from configurational as they can interconvert w/out breaking & reforming bonds

30
Q

What is mutarotation?

A

alpha and beta anomers interconvert in solution

31
Q

Monosaccharides are reducing agents.
-read description in answer

A

•Because of rapid interconversion between 99% ring form and 1% linear form, 100% of glucose molecules in solution can be rapidly oxidised in the reactive (aldehyde) linear form

32
Q

For info on Disaccharides (glycosidic bonds) see lecture.

A
33
Q

What do dissacharides consist of?

How is the bond formed?

A

two monosaccharides joinded covalently by an O-glycosidic bond.

a glycosidic bond can form b/w the hemiacetal group of one monosaccharide and the alcohol group of another

34
Q

What does Maltose consist of?

A

Two D-glucose units joined by a alpha 1-4 glycosidic bond.

-wavy lines indicate it can Beta OG group can freely interconvert with alpha-D-glucose via mutarotation

35
Q

What does Lactose consist of?

A

Composed of D-galactose and D-glucose

-Beta-lactose, contains a beta1-4 glycosidic bond

36
Q

What does Sucrose consist of?

A

Disaccharide of glucose & fructose

NON REDUCING SUGAR

glycosidic bond forms b/w C1 of glucose and C2 of fructose

-bond involves the anomeric C of both monosaccharides =locked configuration, no mutarotation (interconversion) or reducing end (will not oxidise)

37
Q

Are there alpha or beta isomers of sucrose? explain.

A

No.
All the anomeric carbons are involved in bond formation

38
Q

What is a homopolysaccharide?

Name the 3 most important ones and give a brief description of their role

A

Contain only one single type of monosaccharide

  • starch (energy store in plants)
  • glycogen (energy store in animals)
  • cellulose (structural role in plants)
39
Q

What is a heteropolysaccharide?

A

Contain two or more different monosaccharides

40
Q

Which two kinds of homopolysaccharides does starch contain?

A

Amylose (water soluble, simpler structure)

Amylopection (water insoluble, complex structure)

41
Q

Describe Amylose

A
  • linear polymer of D-glucose residues
  • glucose monomers are linked by an alpha1-4 glycosidic bond
  • vary in length, form coiled helical structures
42
Q

Describe Amylopectin

A

branched polysaccharide, consisting of glucose residues joined by:

-alpha1-4 linkages

-alpha1-6 linkages

Branches occur every 24-30 residues

43
Q

Describe Glycogen

A

Glucose homopolysaccharide
-a1-4linkage

-a1-6 linkages

Is similar to amylopectin, but more highly branched. Branches occur every 8-12 glucose residues

44
Q

Describe Cellulose

A

structural homopolysaccharide

water insoluble

similar to amylose, though cellulose is unbranched & linear

BETA1-4 linkages (amylose alpha)

parallel cellulose chains linked together by H bonding

45
Q

SUMMARY OF STRUCTURES AND BOND LINKAGES

(amylose, amylopectin, glycogen, cellulose)

A
46
Q
A

BCM210 (18 decks)

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