Amino acids Flashcards

1
Q

What are the complex polymers that amino acids called?

A

Proteins

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2
Q

What are the 5 components of an amino acid?

A
Chiral carbon centre 
Hydrogen 
Carboxylic acid group 
Amino group 
Variable 'R' group
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3
Q

How many basic amino acids are there?

A

20

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4
Q

What causes the amino acids to be different?

A

Variable ‘R’ chain

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5
Q

What does chiral mean?

A

The central carbon has 4 different groups of atoms attached

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6
Q

Because amino acids are chiral, what does this mean they form?

A

Enantiomers

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7
Q

What are enantiomers?

A

Non-superimposable mirror images

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8
Q

What are the two names for the enantiomers?

A

L

D

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9
Q

What does D stand for?

A

Dextro

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10
Q

What does the D enantiomer do?

A

Rotate plane polarised light clockwise (+)

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11
Q

What does the L stand for?

A

Laevo

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12
Q

What does the L enantiomer do?

A

Rotate plane polarised light anticlockwise (-)

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13
Q

What type of enantiomer are proteins made from?

A

L enantiomers

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14
Q

What two labels can be used for the stereochemistry of amino acids?

A

R and S

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15
Q

How many amino acids have S stereochemistry?

A

18

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16
Q

What stereochemistry do natural protein forming amino acids have?

A

the same L-stereochemistry

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17
Q

What happens to the amino acids in a neutral pH solution?

A

They are ionised to a zwitterion

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18
Q

What is a zwitterion?

A

Dipolar molecule

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19
Q

What becomes charged in an amino acid in a zwitterion?

A

NH2 becomes NH3+

COOH becomes COO-

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20
Q

What is an acidic pKa?

A

2

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21
Q

What is an amides pKa?

A

9-10

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22
Q

When does NH3+ form? Why?

A

In pH = 1 (acidic)

Extra protons in acidic solution so protonates to compensate

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23
Q

When does COO- form? Why?

A

In pH = 11 (basic)

There arent many protons so it de-protonates to make up for it

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24
Q

What is the neutral point called?

A

Isoelectric point

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25
Q

What is an acid?

A

Proton donor

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26
Q

What is a base?

A

Proton acceptor

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27
Q

What is the equation for the equilibrium constant?

A

K = [H+][A-] / [HA]

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28
Q

What is the equation to work out pH?

A

pH = - log K = log 1/K

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29
Q

Which amino acids are natural amino acids? (5)

A
Glycine 
Alanine 
Valine 
Leucine 
Isoleucine
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30
Q

Gly?

A

Glycerine

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31
Q

What side chain does Gly have?

A

H

32
Q

Ala?

A

Alanine

33
Q

What side chain does Ala have?

A

CH3

34
Q

Val?

A

Valine

35
Q

What side chain does Val have?

A

CH(CH3)2

36
Q

Leu?

A

Leucine

37
Q

What side chain does Leu have?

A

CH2-CH(CH3)2

38
Q

Ile?

A

Isoleucine

39
Q

What side chain does Ile have?

A

CH(CH3)CH2CH3

40
Q

Which amino acids have aromatic side chains?

A

Phenylalanine
Tyrosine
Tryptophan

41
Q

Phe?

A

Phenylalanine

42
Q

What side chain does Phe have?

A

CH2-Benzene ring

43
Q

Tyr?

A

Tyrosine

44
Q

What side chain does Tyr have?

A

CH2-benzene-OH

45
Q

Trp?

A

Tryptophan

46
Q

What side chain does Trp have?

A

CH2-Pentagon with one NH substiuted-Benzene

47
Q

Which amino acids contain sulfur atoms?

A

Cysteine

Methionine

48
Q

Cys?

A

Cysteine

49
Q

Met?

A

Methionine

50
Q

What side chain does cysteine have?

A

CH2-SH

51
Q

What side chain does methionine have?

A

CH2-CH-S-CH3

52
Q

Which amino acids have basic side chains?

A

Lysine
Arginine
Histidine

53
Q

Lys?

A

Lysine

54
Q

Arg?

A

Arginine

55
Q

His?

A

Histidine

56
Q

What side chain does Lys have?

A

CH2-CH2-CH2-CH2-NH3+

57
Q

What side chain does Arg have?

A

CH2-CH2-CH2-NH-C(=NH)- NH3+

58
Q

What side chain does histidine have?

A

CH2-Pentagon with 2 substituted N atoms

59
Q

Which amino acids have acid side chains?

A

Aspartate
Glutamate
Asparagine
Glutamine

60
Q

Asp?

A

Aspartate

61
Q

Glu?

A

Glutamate

62
Q

Asn?

A

Asparagine

63
Q

Gln?

A

Glutamine

64
Q

What side chain does aspartate have?

A

CH2-COO-

65
Q

What side chain does glutamate have?

A

CH2-CH2-COO-

66
Q

What side chain does asparagine have?

A

CH2-CONH2

67
Q

What side chain does glutamine have?

A

CH2-CH2-CONH2

68
Q

Which amino acids have a hydroxyl side chain?

A

Serine

Threonine

69
Q

Ser?

A

Serine

70
Q

Thr?

A

Threonine

71
Q

What side chain does Ser have?

A

CH2-OH

72
Q

What side chain does Thr have?

A

CH(OH)-CH3

73
Q

What type of amino acid is proline?

A

Imino acid

74
Q

Which amino acids can be phosphorylated? Which part?

A

Ser
Thr
Lys
OH group

75
Q

Which amino acid can be acetylated?

A

Lys

76
Q

Which amino acid can be hydroxylated?

A

Proline

Ring of proline

77
Q

How do amino acids form proteins?

A

Condensation reaction causes water to be lost and peptide bond to form