Unit 2 - Amino Acids Flashcards
1
Q
What are carbohydrates used for?
A
Energy
Some storage
Structure
2
Q
What are lipids used for?
A
Energy
Storage
Structure
3
Q
What are proteins used for?
A
Energy when caloric intake low
NO STORAGE
Structure
4
Q
What chemicals are used for energy?
A
Carbs
Lipids
Some Proteins (low calories)
5
Q
What chemicals are used for storage?
A
Some Carbohydrates
Lipids
6
Q
What chemicals are used for structure?
A
Carbs
Lipids
Proteins
7
Q
What chemicals are used for regulation?
A
Proteins
8
Q
What are proteins made up of?
A
20 amino acid combinations
9
Q
How many acids are “essential”
A
9
10
Q
What are “essential” amino acids?
A
Not synthesized
From diet
11
Q
How many amino acids are synthesized?
A
11
12
Q
What organ synthesizes amino acids?
A
Liver and kidney
13
Q
How do the liver and kidney synthesize amino acids?
A
Transamination
Deamination
14
Q
What is transamination?
A
Converting one amino acid group into another
15
Q
What is deamination?
A
Degrading amino acid to change it
16
Q
What organs conserve amino acids?
A
Kidney
GI
17
Q
What is the LAST CHOICE for energy use?
A
Amino Acids
18
Q
Which organ reabsorbs amino acids?
A
Kidney
19
Q
Which organ absorbs amino acids? How?
A
GI tract
Digested proteins
20
Q
What is the basic structure of an amino acid?
A
Carboxyl Group
Amino Group
Alpha Carbon
R Group
Hydrogen
21
Q
Why are amino acids named such?
A
Amino (NH2)
Acid (COOH)
22
Q
What is the pH of the carboxyl group?
A
Weakly acidic
23
Q
Alpha Carbon
A
Carbon at center of amino acid
24
Q
Amino Group (Basic structure)
A
NH2
25
Carboxyl Group (Basic structure)
COOH
26
R group
Variable, changes with each a.a.
27
Amino acids contain both...
NH2 (Amino group)
COOH (Carboxyl group)
28
In an acid environment, what is in excess?
H+
29
What happens to the amino and carboxyl groups in an amino acid in Low pH environment?
Both protonated
- COOH retains H+
-NH2 gains H+ --> NH3+
30
Under acid conditions, how does the entire amino acid behave? (Why?)
As a cation, Net pos. charge
NH2 gains H+ = NH3+
31
What is physiological pH?
7.37 to 7.47
32
How does the structure of amino acid in physiological pH differ from the basic structure?
Carboxyl group has no H (COO-)
Amino group has extra H (NH3+)
is an Ampholyte
33
Ampholyte
Both Pos and Neg charges
34
What is another word for Ampholyte?
Dipolar ion
35
What is the charge on amino acid groups in physiological pH?
No Net Charge
36
What is the charge on amino acid groups in acidic pH?
Net Positive Charge
37
Amphoteric definition
Able to act as acid and base
Is a buffer
38
Why are amino acids at physiological groups good buffers?
They can accept or donate H+
(COO- and NH3+)
39
What is in excess in a high pH environment?
OH-
40
What happens to the basic structure of an amino acid in alkaline conditions?
COOH loses H (COO-)
NH2 loses H (NH2)
DEprotonated
41
What is the charge of the amino acid in acidic conditions?
Net NEGATIVE charge
Anion
42
What is a peptide bond
Bond between AMINO end of one a.a. and CARBOXYL end of one a.a.
43
Use "polymer" to describe protein formation
Proteins are polymers of a.a. joined at alpha carbon
44
Protein synthesis
DNA --> Gene --> m-RNA --> Ribosomes --> Protein
45
What is the Isoelectric point? (or PI)
the pH at which a.a. has net neutral charge
46
What determines an a.a. isoelectric point?
R group
47
How does R group determine an a.a. shape and behavior?
R group can be polar (hydrophilic, outside) or non polar (hydrophobic, inside)
48
What happens when amino acids bind?
Peptide bond forms
Water released
49
Why does a peptide bond form water?
OH released from carboxyl group
H released from Amino group
H2O
50
Dipeptides
2 a.a.
1 peptide bond
51
Tripeptides
3 a.a.
2 peptide bond
52
Oligopeptides
UP TO 5 a.a.
53
Oligo- definition
Few
54
Polypeptides
6 to 30 a.a.
55
How many a.a. constitutes a protein?
<40 a.a.
with complex organic compounds (C, H, O, N, S)
56
Proteome
All the proteins an organism can make depending on their genetics
57
Most a.a. diseases are due to..?
Genetic defects
58
Renal aminoaciduria
Normal blood/plasma levels
Kidney CAN't reabsorb a.a.
59
Overflow aminoaciduria
Transport system overwhelmed
High blood/plasma levels
Renal threshold exceeded, reabsorption threshold exceeded
60
Aminoacidopathies
Defect in handling parent a.a.
Parent a.a. in excess
61
Organic acidemias
Issue in catabolic pathway of a.a. (transamination/deamination)
organic acid metabolites in excess
(parent a.a. may or may not accumulate)
62
What is the main treatment of Inborn errors of metabolism?
Dietary avoidance of amino acid
63
When do primary aminoacidopathies appear and why?
Early in life because its genetic
64
When do secondary aminoacidopathies appear and why?
Later in life because acquired
65
Liver disease causes...
a.a. overflow due to accumulation
66
Phenylalanine levels that constitute phenylketonuria
>2mg/dL
phenylalanine:tyrosine ratio high
(inc phenylalanine, dec tyrosine)
67
How is tyrosine produced?
Adding OH to phenylalanine
68
phenylketonuria has a deficiency of what enzyme
phenylalanine hydroxylate`
69
What is formed in place of tyrosine in phenylketonuria?
Toxic phenylpyruvate
70
Enzyme levels in classic PKU
Virtually absent
71
End products and where they build up in Classic PKU
Phenylpyruvate/Phenylketoacids
Builds up in blood, urine, csf
72
How to manage classic PKU?
Diet
no milk, dairy products or aspartame
73
When is newborn screening done for classic PKU?
After sufficient milk feedings
74
What is important to know about pregnant women with PKU?
Toxic products can cross the placenta
75
PKU signs/symptoms
Normal at birth
Failure to thrive, babies
Urine has musty/mousy odor
Phenylalanine inc in blood, urine, CSF
76
PKU Urine
Smells mousy/musty
Turns blue/green with ferric chloride (no longer done in US because genetic screening at birth)
77
What does high levels of phenylalanine do?
Toxic to brain tissue
Irreversible mental retardation
78
Why are PKU patients normally fair skinned?
Tyrosine needed to form melanin
79
Inborn errors of metabolism
Aminoacidopathies
Organic acidemias
80
What is the proportion of inborn errors seen between boys and girls?
Affect them both equally because autosomal recessive
81
Aminoacidopathies are a defect in what?
The handling of parent amino acid
Increase a.a.
82
Organic acidemias are a defect in what?
The catabolic pathway of an amino acid
83
What accumulates in an organic acidemias?
Organic acid metabolites
84
What amino acid becomes an essentiatal a.a. in PKU patients?
Tyrosine
85
Difference between PKU and Tyrosnemia?
PKU can't form tyrosine
Tyrosinemia can't convert tyrosine
86
What is tyrosine a precursor for?
Thyroxine/Thyroid hormones
Melanin
Adrenal hormones
87
Which form of tyrosinemia is more severe?
1
88
What is the enzyme that is deficient in tyrosinemia 1?
Fumarylactoacetate hydrolase at end of pathway
89
What is the enzyme that is deficient in tyrosinemia 2?
Tyrosine aminotransferase at the beginning of pathway
90
How to manage tyrosinemia?
Minimize phenylalanine and tyrosine in diet
91
Why is Tyrosinemia 1 so detrimental?
Because at the end of the pathway, increase of tyrosine and its metabolic products
92
Why is Tyrosinemia 2 less severe?
Because at the start of pathway, only tyrosine is increased, not metabolic products
93
Diseases of Tyrosinemia 1
Cirrhosis
Acute hepatic failure
94
S/S of Tyrosine 1
Hepatosplenomegaly
Photophobia
Ricketts
Tyrosine crystals in urine
95
Diseases of Tyrosinemia 2
Eyes, skin, mental development problems
96
Mousy urine
PKU
97
What enzyme is deficient in Alkaptonuria?
Homogentisic Acid (HGA)
98
What is alkaptonuria?
Dark urine caused by increase of HGA
99
What is the clinical presentation of alkaptonuria?
Dark urine
Arthritis
Pigment cahnges
100
What is a quick way to test for alkaptonuria?
Adding a base to fresh urine
101
What is melanuria?
Malignant melanoma that increases melanogen that is present in urine and causes a dark color upon oxidation
102
Types of Branched Chain Amino Acid Disorders?
Maple syrup urine disease
Organic Acidemia
103
Burnt sugar urine smell
Maple syrup urine disease
104
Sweaty feet urine smell
Organic acidemia
105
What is in accumulation in maple syrup urine disease
Leucine
Isoleucine
Valine
106
What are branched cahin a.a. disorders
Methyl group branches of a.a. chain
107
What a.a. disorder is seen later in life?
Alkaptonuria
108
What is not an amino acid disorder taht affects urine color?
Melanuria
109
Why are branched chain a.a. disorders seen early in life?
Acute ketoacidosis episodes
- Failure to thrive
- Mental retardation and death
110
Diagnostic findings for branched chain a.a. disorder
Inc ketones
Smells
111
What is the most common inborn error of metabolism
Cystinuria
112
What causes cystinuria
Cystine not reabsorbed by the kidney tubule because of lack of enzyme
113
What is elevated in cystinuria?
Cystine
Lysine
Arginine
Ornithine
IN URINE
114
What is the treatment for cystinuria?
Keep urine in alkaline pH to prevent crystal formation
115
What is the best practice for detecting a.a. disorder?
High performance liquid chromatography tandem mass spectrometry (HPLC-MS-MS)
116
Guthrie Test
