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MCAT Biological Sciences > Organic Chemistry > Flashcards

Organic Chemistry Flashcards

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1
Q

What is a functional group?

A

The part of a molecule where most of its chemical reactions occur. It is the part that effectively determines a compound’s chemical properties in addition to many physical properties.

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2
Q

What is an alkyl group?

A

A general, non-aromatic, hydrocarbon obtained by removing a hydrocarbon atom from an alkane.

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3
Q

What does R represent?

A

A general alkyl group

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4
Q

What is the structure of a general primary alcohol?

A
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5
Q

What is an aryl group?

A

Aromatic hydrocarbon group from an arene with a H atom removed.

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6
Q

What is a carboxylic acid? (R group is an Aryl group)

A
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7
Q

What is a phenyl group?

A
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8
Q

What is an alkanoyl (acyl group) group?

A
  • Alkanoyl (alkyl + carbonyl)
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9
Q

What is an acetyl (ethanoyl) group?

A
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10
Q

What is a benzoyl group?

A
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11
Q

What is a nucleophile?

A
  • Nucleophiles are literally “things that love nuclei”. (Nuclei are positively-charged.)
  • Nucleophiles are either negatively-charged, or at least have a negatively-polarized part that is reactive.
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12
Q

What is an electrophile?

A
  • Electrophiles “love electrons”.
  • They are either positively-charged or have a positively-polarized part.
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13
Q

IR spectrum of C=O shows a strong, sharp band between ____ cm-1.

A

IR spectrum of C=O shows a strong, sharp band at **1650-1800 **cm-1​.

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14
Q

IR spectrum of -OH and -NH groups has bands at ____ cm-1.

A

-OH and -NH have intermolecular bonding, causing IR bands to be broad, extanding over a wide region (3600-2700 cm-1)

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15
Q

Alkene

A
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16
Q

Alkane

A
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17
Q

Alkyne

A
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18
Q

Ammonia

A

NH3

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19
Q

Primary, secondary, tertiary, quaternary amine

A
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20
Q

Amide

A
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21
Q

Imine

A
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22
Q

Hydrazone

A
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23
Q

Oxime

A
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24
Q

Nitro

A
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25
Q

Diazo

A
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26
Q

Nitrile/Cyanide

A
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27
Q

Azide

A
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28
Q

Alcohol

A
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29
Q

Ether

A
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30
Q

Aldehyde and Ketone

A
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31
Q

Carboxylic Acid

A
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32
Q

Acyl Halide

A
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33
Q

Anhydride

A
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34
Q

Ester

A
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35
Q

Thiol

A
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36
Q

Sulfide

A
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37
Q

Sulfate

A
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38
Q

Sulfite

A
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39
Q

PBr3

A
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40
Q

Phosphate

A
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41
Q

Phosphite

A
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42
Q

Silane

A
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43
Q

Silicon Dioxide

A
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44
Q

Hypochlorite

Chlorite

Chlorate

Perchlorate

A
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45
Q

Conjugated double bond

A
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46
Q

Multiple bonding:

Increases/decreases bond length

Increases/decreases bond energy

A

Decreases bond length

Increases bond energy

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47
Q

What is an isomer?

A

Same molecular formula, different structural formula

Same in writing, different in drawing

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48
Q
  1. Structural/Constitutional Isomers
  2. Positional Isomers
  3. Functional Isomers
A
  1. Structural Isomers: same molecular formula, different connectivity
    1. Positional Isomers: Structural Isomers that have the same functional groups positioned differently
    2. Functional Isomers: Structural Isomers that have different functional groups
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49
Q

What are geometric isomers?

A

Same molecular formula, same connectivity, but different orientation across a double bond.

  • Cis = same side, Trans = opposite side
  • E/Z when different groups are attached to either side
    • Z = high priority groups on same side
    • E = high priority groups on opposite side
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50
Q

What are stereoisomers?

A

Same molecular formula, same connectivity, but different 3D arrangements across one or more chiral centers

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51
Q

different stereoisomers?

A

2#chiral- (#meso)

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52
Q

What are enantiomers?

A

Mirror images. ALL chiral centers are reversed

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53
Q

What are diastereomers?

A

More than one chiral center, but not all chiral centers are inverted

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54
Q

Are meso compounds optically active?

A

They have chiral centers, but as a molecule they are achiral and optically inactive

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55
Q

Answer with the same or different

  1. Stereoisomers have ___ chemical properties.
  2. Enantiomers have ___ physical properties
  3. Diastereomers have ___ physical properties
A
  1. the same
  2. the same
  3. different
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56
Q

Syn-periplanar

A
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57
Q

Anticlinal eclipsed

A
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58
Q

Gauche vs Anti Staggered Conformational Isomers

A
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59
Q

What are conformational isomers?

A
  • Same molecular formula
  • Same connectivity
  • Same stereochemistry
  • Can rotate about a single bond
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60
Q

Conformers about a single bond (Eclipsed and Staggered)

A
  • Eclipsed
    • Syn-periplanar: highest torsional strain, unstable, bulky groups eclipse eachother
    • Anticlinal eclipsed: high torsional strain, unstable, bulky groups eclipse hydrogens
  • Staggered
    • Gauche: low torsional strain, stable, bulky groups 60° staggered
    • Anti: lowest torsional strain, most stable, bulky groups 180° staggered
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61
Q

Different conformations of cyclohexose?

A
  • Chair: most stable, everything staggered
  • Twist boat: less stable, things not completely eclipsed
  • Boat: least stable, everything is eclipsed
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62
Q

What is polarized light?

A

EM fields in one direction

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63
Q

What is specific rotation?

Left rotation vs Right rotation?

A
  • Specific rotation: chiral molecules containing a single enantiomer will rotate polarized light (“optically active”)
  • l = levorotatory
  • d = dextrorotatory
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64
Q

Assigning R and S

A
  1. Assign priorities
  2. Turn molecule so lowest priority group is at the back
  3. Order 1st, 2nd, and 3rd priority groups
  4. go right- R, go left- L
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65
Q

How to assign priority?

(Cahn-Ingold-Prelog rules)

A
  • Start with atoms directly bonded to chiral carbon
    • Atom with the higher MW has greater priority
    • If atoms are the same, look at the next shell
    • Atom with higher MW on second shell has greater priority
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66
Q

What are racemic mixtures?

A

Mixtures that contain equal amounts of both enantiomers. (Racemate)

Racemic mixtures do not rotate polarized light- optically inactive

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67
Q

How to separate enantiomers?

A
  • Convers enantiomers to diastereomers
  • Separation of diastereomers
  • Convert diastereomers back to enantiomers
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68
Q

In nature, are proteins made of L or D amino acids?

A

Proteins are made of L-amino acids

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69
Q

Phsical properties of hydrocarbons

A
  • hydrophobic
  • LD forces present only
  • lower BP than compounds the same size with functional groups
  • Heptane has same BP as water
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70
Q

Complete combustion

A

Alkane + O2 → CO2 + H2O

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71
Q

What are substitution reactions with halogens?

A

Alkane + halogen + free radical initiator → alkyl halide

  • UV light and peroxides are free radical initiators
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72
Q

Ring strain in cyclic compounds

A
  • Cyclopropane has the highest ring strain
  • Cyclobutane has the second highest ring strain
  • Cyclohexane has the lowest ring strain
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73
Q

What is Angle (Baeyer) and Torsional strain?

A
  • Angle: caused by deviation from the ideal sp3 tetrahedral bond angle of 109.5°
  • Torsional: molecule aving eclipsed conformations rather than staggered
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74
Q

Do bicyclic or monocyclic molecules have more ring strain?

A
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75
Q

Prefix and suffix for alcohols

A

Prefix: hydroxyl, hydroxy

Suffix: -ol, alcohol

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76
Q

Physical properties of alcohols?

A
  • Hydrogen bonding
  • Higher boiling point than the same compound without the alcohol group
  • water soluble
  • IR: 3300 cm-1 and broad due to hydrogen bonding
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77
Q

Substitution reactions (What favors SN1 and SN2)

A

R-OH + HX <–> R-X + H2O

  • SN1: stable carbocation, 3° carbon center, protic solvent
  • SN2: unstable carbocation, primary carbon center, aprotic (but polar) solvent
  • need good LG
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78
Q

SN1

A
  • unimolecular, intermediate carbocation formed
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79
Q

SN2

A
  • bimolecular, passes through transition state
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80
Q

Oxidation of alcohols

A
  • Primary: Oxidized to carboxylic acids by KMnO4 and CrO3, Oxidized to aldehyde by PCC
  • Secondary: always oxidized to ketone
  • Tertiary: do not oxidize
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81
Q

Pinacol rearrangement in polyhydroxyalcohols?

A
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82
Q

How do you protect alcohols? deprotect?

A
  • Protect by adding Cl-SiMe3 to R-OH
  • Alcohol is “capped” into R-O-SiMe3
  • Deprotect: add F-
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83
Q

React Alcohol with SOCl2 and PBr3?

A

R-OH + SOCl2 –> R-Cl (by products: SO2 + HCl)

R-OH + PBr3 –> R-Br (by products: H3PO3, R3PO3, HBr)

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84
Q

Sulfonates

A

R-SO3- (good leaving groups)

  • R = Methane : methanesulfonate
  • R = Toluene : tosylate
  • R = trifluoromethane: triflate
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85
Q

What is esterification?

A

Acid + Alcohol = Ester

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86
Q

What are inorganic esters?

A

Replace C of esters with a different atom

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87
Q

Lower pKa means more or less acidic?

A

more acidic

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88
Q

What effect does branching of hydrocarbons have on physical properties?

A

More branching = higher freezing/melting point, lower boiling point

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89
Q

pKa of:

  1. COOH (carboxylic acids)
  2. ArOH (Phenols)
  3. H2O
  4. ROH (alcohols)
  5. -CH2(CO)-R
  6. -CH2(CO)-OR
A
  1. COOH 5
  2. ArOH 10
  3. H2O 16
  4. ROH 16
  5. -CH2(CO)-R 20
  6. -CH2(CO)-OR 25
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90
Q

Aldehyde suffix?

A

-al, -aldehyde

91
Q

Ketone prefix and suffix?

A
  • Prefix: keto- , oxo-
  • Suffix: -one , ketone
92
Q

Physical properties of ketones

A
  • Polar C=O bond
  • Dipole-dipole interactions give high boiling points (higher than alkanes, lower than alcohols and carboxylic acids)
93
Q

Nucleophilic addition with ketone to form hemiacetal/acetal

A
94
Q

How do make a hemiacetal? an acetal?

A

Aldehydes and ketones react with 1 equivalent of alcohol to make a hemiacetal.

They react w/ 2 equivalents of alcohol to make acetals

95
Q

What is a hemiketal and ketal?

A

Like hemiacetal and acetal but ketone is starting reactant

96
Q

Primary amine + aldehyde or ketone = ?

Secondary amine + aldehyde or ketone = ?

A

Primary amine + aldehyde or ketone = imine

Secondary amine + aldehyde or ketone = enamine

97
Q

Make an imine

A
98
Q

How to make an enamine?

A
99
Q

Haloform reaction of ketone

A
100
Q
  1. Ketone + halogen = ?
  2. Methyl ketone + halogen = ?
  3. Trihalogenated methyl is a good ___ ?
A
  1. Ketone + halogen = **halogenation of alpha C **(adjacent to C=O)
  2. Methyl ketone + halogen = haloform + carboxylate
  3. Trihalogenated methyl is a good leaving group
101
Q

Aldol condensation

A

occurs because of acidic alpha proton

102
Q

Aldehydes oxidize to ____.

What about ketones?

A

Aldehydes oxidize to carboxylic acids.

Ketones do not oxidize further.

103
Q

1,3 dicarbonyls: internal H-bonding

A
104
Q

What is tautomerization?

A

Enol has alcohol, keto has ketone (keto is more stable and predominates)

105
Q

What do organometallic compounds do?

A
  • make R-, which attacks C=O to make R-C-OH
  • Make C-C bonds
  • R-X + Li → R-Li
  • R-X + BuLi → R-Li
  • R-Li + C=O → R-C-OH
106
Q

Organometallic reaction

A
107
Q

Wolff-Kishner reaction?

A

Reduces C=O to -CH2-

C=O + NH2NH2 → -CH2- + N2

108
Q

Wolff-Kishner reaction mechanism

A
109
Q

Grignard reaction

A
  • Grignard reagents produce R-
  • R-X + Mg → R-Mg-X
  • R-Mg-X + C=O → R-C-OH
110
Q

What is the effect of bulky groups on either side of C=O?

A

Steric hinderance- blocks access to electrophilic carbon- reactivity goes down

111
Q

Why is alpha proton of carbonyl group acidic?

A

Alpha proton is acidic because resulting carbanion is stabilized by resonance

112
Q

Resonance structures of beta unsaturated carbonyl

A
113
Q

α,β-unsaturated carbonyl + nucleophile → ?

A

α,β-unsaturated carbonyl + nucleophile → addition of the nucleophile at the β position

  • Nucleophiles attack the β H
114
Q

Suffix for Carboxylic Acids

A

-oic acid, carboxylic acid, -dioic acid

115
Q

Physical properties and solubility of carboxylic acids?

A

High BP due to hydrogen bonding

soluble in water

116
Q
A
117
Q

Nucleophilic attack on COOH

A

Occurs on electrophilic C of C=O

118
Q

Nucleophilic attack on SOCl2 by COOH

A

Nucleophilic attack occurs by nucleophilic O of COOH

119
Q

How do you reduce a carboxylic acid?

A

LiAlH4: COOH → alcohol

120
Q

Decarboxylation reaction of beta-keto acid

A
121
Q

Esterification reaction

A

COOH + ROH under acidic conditions = ester

122
Q

Halogenation of carboxylic acid at the alpha carbon

RCOOH + X2→ halogenation at the alpha carbon

A
  1. Convert to enolizable form (w/ PBr3, make an acyl halide)
  2. Acyl halide enolizes
  3. Halogenate the enol w/ Br2
  4. Revert back to carboxylic acid (or hydrolysis)
123
Q

Substitution reaction

RCOOH + E+ → substitution at the alpha carbon

A
  1. Carboxylic acid converted to acyl halide, which can enolize
  2. Acyl halide tautomerizes to its enol form by abstractino of acidic alpha hydrogen
  3. Halogen (or some other E+) gets attacked by the alpha position
  4. Revert back to a carboxylic acid. The net effect is that the alpha H gets substituted by an electrophile
124
Q

Dimerization?

A

H bonding causes dimerization of carboxylic acids

125
Q

pKa of COOH?

pKa of H+ ?

pKa of water?

A

pKa of COOH = 5

pKa of H+ = 0

pKa of water = 16

(COOH is a weak acid)

126
Q

Inductive effect of substituents at alpha carbon of carboxylic acid

A

EWG makes the acid stronger (helps distribute charge of COO- and stabilize it)

127
Q

Why is COOH a good acid?

A

Conjugate base (carboxylate ion) is stabilized by resonance

128
Q

Acid chloride

  • suffix
  • structure
A
  • suffix = -oyl chloride
129
Q

Anhydride suffix and structure

A

-oic anhydride

130
Q

Amide suffix and structure

A

-amide

131
Q

Ester suffix and structure

A

-oate

132
Q

Can amides hydrogen bond?

A

Yes- amides can hydrogen bond because of the N-H group.

Hydrogen bonding involving the amide backbone of polypeptides form the secondary structure of proteins.

133
Q

What is IR absorption of acid chloride?

A

C=O shows up greater than 1700 cm-1, close to 1800 cm-1

134
Q

How many bands on IR spectrum show up for an anhydride?

A

2 bands between 1700-1800 cm-1

135
Q

Ester IR bands

A

C=O shows up at 1700 cm-1

C-O ether stretch shows up at 1200 cm-1

136
Q

Carboxylic acid + SOCl2 = ?

A

Acid Chloride

137
Q

Carboxylic acid + carboxylic acid + heat = ?

A

Anhydride

138
Q

Acid chloride + carboxylic acid + base =

A

Anhydride

139
Q

Acid chloride + alcohol + base

A

Ester

140
Q

Acid chloride + amine =

A

Amide

141
Q

Acid chloride + water

A

Carboxylic Acid

142
Q

Nucleophilic substitution of acid derivative

A

Nucleophile attacks C of C=O

143
Q

What is the Hoffman rearrangement?

A

Takes away the C=O of an amide.

144
Q

What is transesterification?

A

Ester + alcohol → new ester

145
Q

What is saponification?

A

Hydrolysis of fats and glycerides (esters) to a base

146
Q

Hydrolysis of Amides

A

LG is a neutral amine

147
Q

Relative reactivity of acid derivatives

A

Acid chloride > anhydride > ester > amide

  • Acid halides are the most reactive because halides are good LGs
  • Amides are the most stable derivatives because NR2- is a bad LG. The C-N also has partial double bond character (stable)
148
Q

LG of anhydride

A

carboxylate ion (COO- can redistribute the negative charge via resonance and thus stabilize)

149
Q

Can the C-N bond of an amide rotate?

A

No- it has double bond character

Rings with amides have higher strain

beta-lactam: 4-membered ring with 1 amide

150
Q

What is the beta-lactam?

A

4-membered ring with 1 amide

Has higher ring strain (double bond character of amide)

151
Q

Structures of:

  • alpha-keto acid
  • beta-keto acid
  • beta-keto ester
A
152
Q

What is decarboxylation?

A

beta-keto esters → beta-keto acids → enols → ketos

153
Q

Acetoacetic ester synthesis

(Acetoacetic ester condensation)

A
154
Q

Acetate Structure

Acetoacetate structure

A
155
Q

Process of acetoacetic ester synthesis

A
  1. acidic alpha proton comes off, resulting carbanion attacks new R group
  2. Hydrolysis of ester turns it into a β-keto carboxylic acid.
  3. β-keto acids undergo decarboxylation because β-keto group stabilizes the resulting carbanion via enol formation.
  4. Net effect: R group is made to attach to the alpha carbon of acetone
156
Q

Acidity of alpha H and beta-keto ester

A

H alpha to a carbonyl group is more acidic than a regular H

157
Q

Keto-enol tautomerism

A
158
Q

Extraction technique

A
  • Solutes are distributed between two immiscible solvents
  • Organic phase usually less dense than aqueous phase. EXCEPT chloroform, which is more dense.
159
Q

Distillation

  • separates liquids based on ___.
  • Simple distillation
  • Fractional Distillation
  • Vacuum Distillation
A
  • Separates liquids based on boiling point
  • Simple distillation: done with a normal column, separates 2 liquids with large difference in BP
  • Fractional distillation: done w/ fractionating column, separates liquids with smaller differences in BP
  • Vacuum distillation: under low pressure, lowers BP for all components, doesn’t require increasing T as much
160
Q

General chromatography

A
  • Molecules move slower if more attracted to stationary phase and repelled by mobile phase
  • Molecules move faster if attracted to the mobile phase and repelled by stationary phase
161
Q

What is gas chromatography?

A
  • stationary phase is a liquid coated on inside of a column
  • Mobile phase is gas
  • Substrate equilibrates between mobile (gas) and stationary (liquid coat) phase
  • Substances w/ greater affinity for stationary phase come out of column slower.
  • Polar substrate has more affinity for polar stationary phase, hydrophobic substrate has more affinity for hydrophobic stationary phase
162
Q

Paper chromatography

A
  • solvent = mobile phase, paper = stationary phase
  • Separate pigment in dyes
  • Pigments stick to paper
  • Rf value = dpigment/dsolvent front
    • Rf=0 : pigment has not moved
    • Rf=1 : pigment moved as far as solvent
163
Q

Thin-layer chromatography?

A
  • Like paper chromatography
  • Instead of paper, use a plate coated with a specific stationary phase of your choosing
164
Q

Recrystalization

A
  • Barely dissolve compound, let it recrystalize out of solution, compound ends up more pure
  • Use just enough solvent to make a warm saturated solution
  • As solution cools, solubility decreases, compound comes out of solution
  • Choose a solvent that your compound is soluble in at a warm temp, but not at a cool temp
  • Impurities should be highly soluble in solvent at all temperatures
165
Q

IR Spec: vibrations and rotations

A
  • Vibrations: bonds can stretch, compress, and bend like a spring
  • Rotations: molecules rotate, most produce waves in microwave region, which overlaps with vibration spectra
166
Q

What is on IR Plot?

A
  • Transmittance vs. decreasing wavenumber
167
Q

What groups have bands around 3000 cm-1 on IR spectrum?

A

Anything with a H atom (O-H, N-H, C-H)

168
Q

Anything 2000 cm-1 and below does not involve ___. Some examples are…

A

Does not involve H.

C=O, C=C, C-C, C-O

169
Q

Where does the carbonyl group absorb on the IR spectrum?

A

1700 cm-1

170
Q

What is at 3300 cm-1 on IR spectrum?

A

O-H, N-H, or alkyne C-H

  • O-H is the broadest, N-H is slightly sharper, alkyne C-H is very sharp
  • Broad peaks are due to H-Bonding in O-H and N-H
171
Q

Primary colors of pigments vs. light?

A

Primary colors of pigments (yellow, magenta, cyan) is exactly the complementary colors of the primary colors of light

172
Q

___ absorbs blue light and reflects the others into your eyes. The absence of blue produces yellow.

A

Carotene

173
Q

Colors of universal indicator

A

Red - very acidic

Orange - acidic

Yellow - weakly acidic

Green - neutral

Blue - basic

Purple - very basic

174
Q

Conjugated systems ____ the energy of electromagnetic radiation that is absorbed.

The more conjugated double bonds there are the ___ the wavelengths of absorbed radiation.

A

Conjugated systems decrease the energy of electromagnetic radiation that is absorbed.

The more conjugated double bonds there are the longer the wavelengths of absorbed radiation.

175
Q

What is mass spectroscopy?

A
  • bombard a molecule into electrons- it is fragmented into ions
  • faster electrons produce more fragmentation and smaller molecular ion peaks
  • relative abundance vs. m/z (mass to charge ratio)
  • Magnetic field resolves the different ions
  • Peaks clustered close together are isotopes
  • parent peak = molecular ion peak (depicts the ion without fragmentation)
  • Base peak is the tallest (most abundant)
176
Q

What is mass spec useful for?

A
  • measuring molecular weight of a molecule
  • identify the molecule by fragmentation patters
  • identify heteroatoms by their characteristic isotope ratios
177
Q

NMR values in ppm

  1. carboxylic acid
  2. aldehyde
  3. Ph-H, Ph-OH, amide
  4. -CH=
  5. -CHX-
  6. alkyne H, R-OH, R-NH2
  7. alkane H
A
178
Q

NMR

  • What does it measure?
  • What is H sheilded by?
  • What is H desheilded by?
A
  • Measures chemical shift relative to a standard called TMS (tetramethylsilane) in ppm
  • The more “different” two protons are, the farther their chemical shifts
  • H is shielded by C, because C is not so electronegative
  • H is deshielded by O, because O is electronegative
179
Q

NMR

  • More shielded protons appear ___
  • More deshielded protons appear ___
A
  • More shielded protons appear upfield (to the right)
  • More deshielded protons appear downfield (to the left)
180
Q

NMR signals by n equivalent protons add up to produce…

A

One signal the height n times the signal for a single proton

181
Q

Spin-spin splitting

A
  • Produced by neighboring protons (Attached to adjacent atoms)
  • Split into n+1 peaks
  • J value defines how far apart things get split
  • Protons across single and aromatic bonds get split approximately the same
  • Protons across double bonds get split farther apart
182
Q

Amines

  • Prefix
  • Suffix
A
  • Prefix: amino-
  • Suffix: -amine
183
Q

Are 3° amines chiral? are 4°?

A
  • 3° amines can be chiral, but the proton comes on and off. Always racemic because of spontaneous inversions.
  • 4° amines can be chiral and stay chiral
184
Q

IR absorption of 1°, 2°, and 3° amines.

A
  • Primary amines (R-NH2) - 2 peaks around 3300 cm-1
  • Secondary amines (R2-NH) - 1 peak around 3300 cm-1
  • Tertiary amines (R3-N) - 0 peaks (no N-H bonds)
185
Q

Amide formation?

A

Amine + Acid derivative → amide

186
Q

Important biological amide formation?

A

Peptide bond formation in protein synthesis (amine + carboxylic acid = amide)

187
Q

Amine reaction with Nitrous Acid

(How is N in nitrous acid attacked?)

A

Ar-NH2 + HONO → Ar-N2+ + H2O + OH-

  • Nitrous acid = HNO2 = HONO
  • HONO → NO+ + OH-
188
Q

Alkylation of Amine

A
189
Q

Hoffman Elimination

A

Amine + Methyl Iodide → exhaustive methylation of amine → elimination w/ methylated amine as LG

  • Unlike E1 reactions where more substituted double bond is formed (Zaitsev), Hoffman Elimination uses less substituted double bond (Hoffman)
190
Q

Are amines basic or acidic?

A

Amines are basic. They like to gain a proton.

R-NH2 → R-NH3+

  • Difficult for neutral amines to lose a proton
  • An amide can lose a proton more easily
191
Q

Is an amine an EWG or EDG?

A

EDG

192
Q

Electron ___ groups increase the basicity of aromatic amines.

Electron ___ groups decrease the basicity of aromatic amines.

Anything ortho to the amine will ___ the basicity.

A

Electron donating groups increase the basicity of aromatic amines.

Electron withdrawing groups decrease the basicity of aromatic amines.

Anything ortho to the amine will decrease the basicity.

193
Q

What is a carbohydrate?

Prefix?

Suffix?

A
  • Carb is a sugar, monosaccharide, disaccharide, polysaccharide
  • Prefix: deoxy
  • Suffix: -ose
194
Q

Classification of carbs

  1. Aldose
  2. Ketose
  3. Pyranose
  4. Furanose
  5. # ose
A
  1. Aldose: sugars with aldehyde group
  2. Ketose: sugars with ketone group
  3. Pyranose: sugars in 6-membered ring
  4. Furanose: sugars in 5-membered ring
  5. # ose: sugar with # carbon atoms
195
Q

To be a carb, a molecule must have:

A
  • At least a 3-Carbon backbone
  • an aldehyde or ketone group
  • At least 2 hydroxyl groups
196
Q

What are the smallest carbohydrates?

A
197
Q

3 most common monosaccharides

A

glucose, fructose, galactose

198
Q

Structure of Glucose

A
199
Q

Structures of Fructose and galactose

A
200
Q

Sugar that makes up RNA? DNA?

A

Ribose makes up DNA. Deoxyribose makes up DNA.

201
Q

What is sucrose?

A

disaccharide made from α-glucose and β-fructose joined at the hydroxyl groups on the anomeric carbons (making acetals)

202
Q

What is lactose?

A

Disaccharide made from β-galactose and α/β-glucose joined by a 1-4 linkage.

203
Q

What is starch?

A

Glucose molecules joined by α1-4 linkage.

204
Q

What is glycogen?

A

Same as starch. Glucose molecules joined by α1-4 linkage, but with additional α1-6 linkage for branching.

205
Q

L and D glucose

A
206
Q

Glucose ring formation

A

Glucose forms a pyranose when C5 attacks the carbonyl carbon

207
Q

How to convert a Fischer projection to cyclic form

A
  • -OH groups on the Left become Up
  • -OH groups on the Right become Down
  • -OH group on the anomeric carbon is up (beta) or down (alpha)
  • CH2OH group on C5 points up for D, down for L
208
Q

Epimer?

Anomer?

A
  • Epimer: different configuration in just one chiral carbon
  • Anomer: different configuration in the chiral, anomeric C when the molecule is in cyclic form
  • Anomers are special types of epimers
209
Q

What is a glycoside linkage? How is it hydrolized?

A
  • Acetal linkage involving the hydroxyl group of the anomeric carbon
  • Glycoside linkage can also mean the linkage between the sugar and the base in nucleotides
  • Hydrolized same way as acetal bond is hydrolyzed
  • glycoside + H2O + catalyst → hydrolysis.
    • Amylase is catalyst for starch
    • Glycosylase for nucleotide
210
Q

L and D amino Acids

A

L are more common in nature

211
Q

At low and high pH, amino acids exist in what forms?

A
  • low pH: cationic
  • high pH: anionic
  • pH=pI : neutral zwitterion
212
Q

Acidic amino acids

A

Aspartic acid, glutamic acid

(R contains carboxylic acid)

213
Q

Basic Amino Acids

A

Lysine, Arginine, Histidine

(R contains amine)

214
Q

How is peptide bond formed? (amide linkage)

A
215
Q

How are peptide bonds hydrolyzed?

A

Requires a strong base or a biological enzyme

216
Q

Primary and Secondary structure of proteins

A
  • Primary structure: sequence (N terminus to C terminus)
  • Secondary structure:
    • repetitive motifs from backbone interactions
    • H-Bonding between NH and C=O
    • alpha helices and beta sheets
    • alpha helix is right handed (R groups stick out)
    • Beta sheets: R groups stick out above and below sheet
217
Q

What are steroids?

A

Made from the cyclization of squalene (a terpene)

  • Cholesterol
  • Testosterone
  • Estrogen
218
Q

What is a terpene?

A
  • Polymerization of isoprene
  • Squalene has 6 isoprene units
219
Q

How to form triacyl glycerol?

A

Glycerol + 3 Fatty acids → Triacyl Glycerol.

220
Q

Structure of phosphoric acid

A

H3PO4

221
Q

Pyrophosphate?

A

Simplest phosphoric acid anhydride

222
Q

Where are phosphodiester bonds found? Phosphoester bonds?

A

Phosphodiester bonds link together the DNA and RNA backbone.

Phosphoester bonds link the phosphates to sugar in ATP.

223
Q

Wittig reaction

A

Carbonyl + Phosphorus Ylide → Alkene

224
Q
A

MCAT Biological Sciences (2 decks)

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