Brainscape's Knowledge GenomeTM

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


See full index

BIOCHEM*2580 > Second Half I F24: Lecture Slides 34 - 57 > Flashcards

Second Half I F24: Lecture Slides 34 - 57 Flashcards

1
Q

What are sugars considered to be?

A

The most abundant biomolecule on earth.

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

What are sugars important in?

A

Energy Metabolism

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

What are sugars essential components of?

A

Nucleic Acids

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

What are Monosaccharides?

A

Consist of a single sugar unit (Glucose)

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

What are Oligosaccharides?

A

Short chains of Monosaccharide Units (Sucrose)

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

What are Polysaccharides?

A

Polymers of 20 or more sugar units (Glycogen, cellulose)

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

What are the 4 chemical properties of Monosaccharides?

A
  • Very water soluble
  • Poorly soluble or insoluble in organic solvents such as ether or hexane.
  • Colourless
  • Sweet to Taste
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the approx. chemical formula of Monosaccharides?

A

(CH2O)n

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

What are the two organic functional groups that combine to make a monosaccharide?

A

A carbonyl (C = O) group , which can either be an aldehyde or ketone and at least two carbons bearing hydroxyl (alcohol) C - OH groups

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

What do the simplest carbon atoms contain?

A

Three carbon atoms (Trioses)

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

What do each of the trioses have?

A

They have aldoses and ketoses: aldotriose and ketotriose

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

What is glycerol considered to be?

A

An aldose

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

What is acetone considered to be?

A

A ketoses

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

What did Emil Fischer study?

A

He studied the analysis, synthesis and stereochemistry of simple sugars, and he introduced much of the terminology and notation that we use today

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

What is the Fischer projection formula?

A

To represent three dimensional sugar structures on paper

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

In the Fisher projection formula, how are vertical bonds represented?

A

Behind the plane

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

In the Fisher projection formula, how are horizontal bonds represented?

A

Project out of the planar

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

What is the Perspective Formula?

A

Solid Wedge-Shaped Bonds Project in front

Dashed bonds point away

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

What are the carbon atoms in Monosaccharides?

A

Asymmetric (4 different substituents)

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

What do all monosaccharides except dihydroxyacetone contain?

A

One or more chiral carbon atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does chiral carbon atoms give rise to?

A

The occurrence of optically active isomeric forms (a type of stereoisomer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are D Glyceraldehyde and L Glyceraldehyde?

A

Enantiomers (mirror images)

23
Q

What are mirror images?

A

Differ in Configuration at every chiral carbon atom (can’t be superimposed)

24
Q

What are the chemical properties of Mirror images

A

Identical (melting point, water-solubility)

25
Q

What do mirror images differ in?

A

Optical activity

26
Q

What is Optical Activity?

A

The plane of polarization of polarized light is bent in opposite directions when passing through solutions of the two enantiomers

27
Q

What are Diastereomers?

A

More then one chiral carbon atoms that have stereoisomers that differ in hardness at some carbon atoms but not others (not mirror images)

28
Q

Do diastereomers have identical chemical properties?

A

They do not have identical chemical properties, because the spatial relationships among the atoms making up the molecules are different

29
Q

When would a sugar be called a “D” sugar?

A

If the chiral carbon atom furthest away from the carbonyl group has the same configuration as D-glyceraldehyde.

30
Q

What are “L” sugars?

A

Those with a configuration similar to L-glyceraldehyde

31
Q

What configuration are most naturally occurring sugars in?

A

D-sugars

32
Q

What are Epimers?

A

A pair of sugars that are identical expect for one configuration at one carbon atom (at the chiral centre they have one identical structure at one carbon)

33
Q

What are epimers a special case of?

A

Diastereomers

34
Q

What is the formula for figuring out the number of stereoisomers?

A

2^n (the power is the # of chiral centres)

35
Q

What is an example of the number of stereoisomers for n chiral centres of aldose?

A

An aldose have 5 carbons with 3 chiral centres

2^3 = 8 stereoisomers.

36
Q

What happens to D-ketoses every time a C atom is added?

A

The number of isomers doubles

37
Q

What is the general trend with D-Aldoses?

A

A aldose has one more chiral centre than a ketone, so the number doubles.

38
Q

What do Aldehydes and Ketones produce when they react with alcohols?

A

Hemiacetals and Hemiketals

39
Q

What happens to the original carbonyl carbon upon the formation of hemiacetals and hemiketals?

A

It becomes chiral

40
Q

What is the hemiacetal and hemiketal formation?

A

Intramolecular: the alcohol and the aldehyde (or ketone) are present in the same molecule

41
Q

What does hemiacetal and hemiketal formation turn sugars into?

A

Ring structures

42
Q

What does the OH group at C-5 react with?

A

The carbonyl carbon of the aldehyde group to form a stable six-membered ring.

43
Q

What does the OH group reaction render?

A

A C-1 asymmetric giving rise to two stereoisomers (a and b)

44
Q

What do these isomeric forms differ in?

A

Only in their configuration around the hemiacetal or hemiketal carbon

45
Q

What is the difference in the configuration around the hemiacetal or hemiketal carbon called?

A

An anomer

46
Q

What does the electrophilic carbonyl carbon atom react with?

A

The nucleophilic O of an OH group

47
Q

What is solid glucose found in?

A

Either in the alpha or the beta form of the hemiacetal

48
Q

What happens as it dissolves in water?

A

It slowly converts into an equilibrium mixture of the alpha, beta and linear forma.

49
Q

What is the process of it converting into the equilibrium mixture called?

A

Mutarotation

50
Q

What happens with time?

A

A solution of a-D-glucose and b-D-glucose form identical equilibrium mixtures with identical optical properties

51
Q

What is the approximate composition?

A

1/3 a-D-Glucose, 2/3 B-D-Glucose, and trace amounts of linear form.

52
Q

What are the two rings formed when sugars cyclize?

A

Pyranose (6-membered) or Furanose (5 membered)

53
Q

What does the size of the ring formed by a particular sugar depend on?

A

The relative thermodynamic stabilities of the various possible ring structures, and this depends on the particular geometry of the molecule.

BIOCHEM*2580 (21 decks)

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