Brainscape's Knowledge GenomeTM

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


See full index

BIOL1026/28 Chemistry of Life > stereoisomerism (2) > Flashcards

stereoisomerism (2) Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

enantiomers

A

pair of isomers - mirror images are not superimposable

molecules have chirality

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

example - ethanol

A

mirror able to rotate and is same as original therefore not enantiomers
and are achiral

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

example - lactic acid

A

rotate 180 - different to original as OH is above the plane while original is OH is below the plane
enantiomer - mirror image is not superimposable - chiral

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

example - erythrose

A

mirror image differ - enantiomer

chiral but have 2 stereogenic centres on both - opposite chirality in mirror image

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

chiral

A

not superimposable with mirror images

can derive from other sources and doesn’t always contain stereogenic centres

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

optical rotation

A

all physical properties of enantiomers are identical except optical rotation

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

chiral molecules in optical rotation

A

plane polarised light pass through solution and remains

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

achiral molecules in optical rotation

A

plane polarised light pass through solution - rotation in light

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

angle of rotation in polarimeter

A

angle alpha depend on concentration of solution (c), path length (l) and specific rotation [a] - characteristics of molecules

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

equation of characteristics of molecules

A

a = [a].D.c.l

temperature and wavelength dependent

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

racemic mixture

A

1:1 mixture of enantiomers

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

enantioenriched

A

ratio not 1:1 mixture

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

enantiopure/homochirality

A

no other enantiomer

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

Diastereomers

A

pair of stereoisomers - don’t bear mirror images relation

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

examples of diastereomers

A

threose and erythrose
glucose and galactose
they have same constitution but different arrangement of atoms and not mirror image

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

having >1 stereogenic centre in diastereomers

A

need at least one stereogenic centre that is different

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

epimer

A

diastereomer where only one out of some stereogenic centre is different

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

example of epimer

A

glucose and galactose - 5 SC and 1 is different

19
Q

example of each diastereomer having corresponding enantiomer

A

D-erythrose and L-erythrose

20
Q

mesoform

A

structure has SC but are achiral

21
Q

example of mesoform - 2-tartaric acid diastereomer

A

rotate 180 horizontally and will be same

superimposable but one chiral and other is achiral

22
Q

geometric isomers

A

stable entities and can’t easily interconvert

compounds with different chemical and physical properties

23
Q

geometric isomers in alkene

A

focus on relative positions of substituents of C=C - cis/trans (same or opposite side horizontally respectively)

24
Q

geometric isomer in ring structure

A

cis and trans - same and opposite side of ring plane

used to describe different substituent - 2 different on same side - cis

25
Q

Fischer representation

A

uses horizontal and vertical lines

using highest priority at apical position located at top end

26
Q

horizontal lines in fischer

A

located in front of plane

27
Q

vertical lines in fischer

A

located behind plane - carbon chain

28
Q

relation of sawhorse and fischer

A

substituent located on same side in Fischer = different sides in sawhorse

29
Q

which representation used for carbohydrates and amino acids

A

Fischer representation

30
Q

CIP nomenclature used:

A

alkene geometric isomer - E/Z

SC(differentiate enantiomers/diastereomer - R/S

31
Q

CIP

A

Catin Ingold Prelog
absolute configuration
differentiated by unambiguous nomenclature

32
Q

How CIP nomenclature works

A
  • identify substituent C=C or SC
  • assign priority sequence based on atomic mass
  • from priority assign E/Z or R/S
33
Q

E

A

entgergen - across

34
Q

Z

A

zusammen - together

35
Q

Nomenclature in SC - process

A
  • see 4 atoms directly bonded to SC
  • priority sequence based on atomic mass
  • assign R/S - by placing lowest priority at back of plane and go from highest to lowest to see if it is going clockwise (R) or anticlockwise (S)
36
Q

if 2 atoms are identical when looking at the nomenclature

A

look at next atom - what they are bonded to

37
Q

atoms with double or triple bonds in Nomenclature

A

given single bond equivalences

38
Q

phantom atom

A

new carbon representing double of triple bonds

39
Q

when having 2 SC

A

2 enantiomers having S,S and R,R

40
Q

R,R and R,S

S,R and S,S

A

diastereomer pair of compounds - determining absolute configuration of SC - compare molecules and see if they’re enantiomers/diastereomer/ just equal to each other

41
Q

example of 2SC in 2 enantiomers

A

L/D-erythrose and L/D-threose

42
Q

why this is important

A

most biological isomers - amino acids, nucleic acids, FA, cholesterol to proteins and other polymers
increase in complexity

43
Q

example of important biological isomer

A

thalidomide - R - nausea-treatment but S- cause birth defects

44
Q

absolute configuration

A

spatial arrangement of atoms of chiral molecule

BIOL1026/28 Chemistry of Life (20 decks)

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