Exam 1 (AA's, Proteins, Non-Protein Nitrogens) Flashcards
(165 cards)
1
Q
20 amino acids are divided into two groups:
A
Essential
Non-essential
2
Q
How are essential amino acid supplied:
A
through diet when we eat proteins
3
Q
How are non-essential amino acids supplied:
A
They are made from the essential amino acids, converted by liver enzymes
4
Q
This is the transfer of one amine group from 1 amino acid to another, done by liver enzymes to make new amino acids from recycled ones:
A
transamination
5
Q
The removal of an amino group from an amino acid; produces ammonia which is converted to urea and excreted in urine:
A
Deamination
6
Q
Amino acids consist of these parts:
A
Amino group
Carboxyl group
Hydrogen
R-group
7
Q
Formation of a peptide involves the ___terminal end of one amino acid reacting with the ___terminal end of another through this type of reaction:
A
C-terminal, N-terminal hydrolysis reaction (H2O is released)
8
Q
Define polypeptide:
A
chain of amino acids linked via peptide bonds
9
Q
Why are amino acids zwitterions:
A
Amino has + charge
Carboxyl group has - charge
*net charge = 0
*makes them good buffers
10
Q
Describe secondary peptide structure:
A
coiling into helix by h bonds of neighboring peptides
11
Q
Describe tertiary peptide stucture:
A
Folding of peptide chain by many forces
12
Q
The interaction of the polypeptides results in a :
A
protein
13
Q
Proteins have ___ main stages of assembly:
A
Primary, Secondary, Tertiary, Quaternary
14
Q
T/F All proteins contain all 20 amino acids:
A
False
15
Q
When errors in metabolism occur, these can build up in blood and urine and be detected by the lab:
A
amino acids
16
Q
T/F When certain amino acids accumulate in blood, they can be toxic and result in death:
A
True
17
Q
What are the two categories of aminoacidopathies:
A
Primary
Secondary
18
Q
Describe primary vs secondary aminoacidopathy:
A
- Primary: inherited defect in enzymatic pathway
* Secondary: disease of a specific organ where amino acid is synthesized (liver, kidney)
19
Q
List the 6 Primary (inherited) amioacidopathies:
A
Alkaptonuria Cystinuria ??? Homocystinuria Maple Syrup Urine Phenylketonuria Tyrosinemia
20
Q
In alkaptonuria, what enzyme is inhbitied, and what builds up:
A
- enzyme: homogentisic acid oxidase
* builds up: homogentisic acid
21
Q
Which aminoacidopathy creates a buildup of homogentisic acid, causing generalized pigmentation and arthritic-like degeneration:
A
Alkaptonuria
22
Q
In alkaptonuria, this will happen to urine up standing, and is caused by a buildup of what:
A
- urine will darken
* buildup of homogentisic acid
23
Q
Cystinuria is not an enzymatic defect, but a defect in _____ _____:
A
renal absorption
24
Q
Buildup of cysteine causes:
A
renal calculi (cysteine stones)
25
This aminoacidopathy is caused by a defect in Branched Chain Ketoacid Dehydrogenase:
Maple Syrup Urine Disease
| MSUD
26
What builds up in MSUD:
Ketoacids (leucine, isoleucine, valine)
27
What signs/symptoms result from MSUD:
* maple syrup smell in urine, skin, breath
* mental retardation
* convulsions
* acidosis
* death
28
What is the defect in MSUD:
the defect is in the Branched Chain Ketoacid Dehydrogenase
| ketoacids then buildup
29
What is the defect in Type 1 Tyrosinemia:
FAA hydrolase (most severe)
30
Which type of Tyrosinema is most severe?
Type 1
31
What is the defect in Type 2 Tyrosinemia:
Tyrosine aminotransferase
32
What builds up in both types of Tyrosinemia?
Tyrosine
| it needs to be broken down for complete amino acid metabolism
33
What does Type 1 tyrosinemia cause:
severe liver disease
| death in infants
34
What does Type 2 Tyrosinemia cause:
eye involvement and skin lesions
35
What amino acid is not metabolized in Homocysteinuria:
Methionine
36
The enzyme Cystathionine B-synthase is blocked in _______, causing a buildup of this amino acid:
* Homocysteinuria
| * Methionine
37
This aminoacidopathy is similar to Marfan's Syndrome:
Homocysteinuria
38
List some signs and symptoms of Homocysteinuria:
* mild to severe cases
* mental retardation
* lens dislocation in eye= nearsightedness
* chest deformities
* long, spindly limbs
* scoliosis
* thrombosis (Increased homocysteine levels can lead to CVA)
39
Increased levels of this amino acid can lead to CVA:
Homocysteine
40
This causes a buildup of phenylalanine and causes severe mental retardation if not treated:
PKU
41
For mandated amino acid testing, is it required that an effective treatment must be available:
yes
42
List the requirements for state mandated amino acid testing:
1) high incidence disorder
2) must have effective treatment available
3) inexpensive screening for high volume
4) test has high sensitivity/specificity
43
T/F Blood sample for amino acid testing must be drawn after 6-8 hour fast and avoiding absorbed dietary proteins:
True
44
Why must you be careful to avoid WBC and PLT when aliquotting specimen for amino acid testing:
they contain amino acids
45
What do you do with an aliquotted blood specimen for amino acid testing:
de-proteinize (aliquot) and freeze immediately
46
T/F Random urine can be used for amino acid test screening:
True
47
When using urine to test for amino acids, this is required for confirmation:
24 hour urine
48
What is the card test used to screen newborns for aminoacidopathies/PKU:
Guthrie test
49
Describe the Guthrie test:
1) start with culture of Bacillus subtilis (requires phenylalanine to grow)
2) add inhibitor to media to prevent bacteria from growing
3) add blood sample
* positive = bacteria will grow (still need confirmation)
* negative = no bacterial growth
50
Why will the Bacillus subtilis grow in the Guthrie test if the patient has PKU:
If defect exists, blood will contain much phenylalanine, feeding B. subtilis
51
Amino acid testing requires ___-____ filtrate:
protein free
52
What other methods can be used to test for amino acids:
* TLC
* Ninhydrin (stains aa's blue)
* HPLC
* Capillary electrophoresis
* MS/MS
53
PKU is caused by a defect in the gene that helps create the enzyme _____:
phenylalanine hydroxylase
54
What type of test of albumin is run for short term blood sugars:
glycosylated albumins
55
Albumin is this type of reactant:
Negative phase reactant
56
Which blood sample has highest protein concentration:
plasma (contains the protein fibrinogen)
57
Which is preferred for protein testing, serum or plasma:
serum (does not contain the protein fibrinogen)
58
T/F Urine and CSF have protein in them:
True, but smaller quantities so need to concentrate samples if quantitating
59
Are proteins too large to pass through vessels?
Yes
60
The presence of protein draws water; distributing extracellular fluid between vascular bed and interstitial space, keeps water out of tissues, maintaining this:
oncotic pressure
61
The presence of ___ differentiates proteins from carbohydrates and lipids:
Nitrogen
62
Proteins denature when ____ and ____ structure bonds break:
Tertiary and Quaternary
63
List methods of denaturing proteins:
* heat
* pH
* Enzymatic action
* heave metals
* urea exposure
* UV light
64
The function of albumin:
maintain osmotic pressure
| keep fluid in vessels and out of tissues
65
T/F Proteins can act as pH buffers:
True. They are amphiprotic zwitterions.
66
These can act as hormones/hormone receptors:
Proteins
67
List some functions of proteins:
* Aid in coagulation
* Transport mechanism (carries things insoluble in fluid- bili, lipids,etc)
* Antibodies
68
Proteins are classified into these two groups:
* Simple proteins
| * Conjugated proteins
69
Albumin, immunoglobulins, hemoglobin are examples of this type of protein group:
Simple proteins
70
Define conjugated proteins:
Protein + non-protein group
71
Metalloproteins, lipoproteins, glycoproteins, mucoproteins, and nucleoproteins are examples of:
Conjugated proteins
72
Give an example of the following:
* metalloprotein:
* lipoprotein:
* glycoprotein:
* nucleoprotein:
* Ferritin
* Cholesterol, Triglycerides
* Haptoglobin, Alpha-1-Antitrypsin
* Cellular chromatin
73
_____ + _____ = Total Protein
Albumin + Globulin
74
Total Protein ref. range:
6-9 g/dL
75
_____ makes up 60% of the total proteins
Albumin
76
Which are measured directly in lab, which are calculated values-
* Albumin:
* Total Protein:
* Globulins:
* Alb= direct
* TP= direct
* Globulins= calculated (TP-ALB= globulins)
77
Ref range for Globulins:
2.5 - 4 g/dL
78
How do you calculate Globulins:
TP - Alb = globulins
79
There are how many main globulins:
4
| alpha-1, alpha-22, beta, gamma
80
Disruption of the A/G ratio can indicate this:
disease
81
TP < 3.0 g/dL, decrease on oncotic pressure:
Transudate
82
TP > 3.0 g/dL, excreted by cells:
Exudate
83
T/F Individual Fractionation of proteins often more important than Total Protein alone:
True
84
This test can replace the HgA1C:
Glycosylated Albumin
85
This protein has many functions, including transporting bilirubin, steroids, thyroid hormones, fatty acids, iron:
Albumin
86
Albumin testing is quantitated by this method:
dye binding directly to albumin
| color of dye changes once bound, color difference proportional to amount of albumin
87
What dyes are used for albumin quantitation:
1) Bromcresol green (HgB binds well, must avoid hemolysis)
| 2) Bromcresol purple (bilirubin will bind)
88
Which dye in Albumin quantitation will bind hemoglobin, and which will bind bilirubin:
* bromcresol green: binds Hgb
| * bromcresol purple: binds bilirubin
89
Increased albumin levels indicate:
not typically significant. Can be seen in temporary dehydration.
90
Decreased albumin levels indicated:
* malnutrition
* liver disease
* nephrotic syndrome
* chronic inflammation
91
What are two methods for albumin quantitation:
1) Kjedahl
| 2) Biuret (most current)
92
What is being tested for in Kjedalh method vs Biuret method for albumin quatitation:
* Kjedahl: determining Nitrogen content (must denature protein first to release N)
* Biuret: testing for peptide bonds in protein (no need to denature)
93
This describes what method:
* denature protein to release Nitrogen
* N converted to NH4
* NH4 reacts w/ Nessler's reagent= color change
* color product is measured via spectra
Kjedahl method for albumin quantitation
94
These steps describe what method:
* Copper sulfate solution binds to peptide bonds in alkaline solution = color change
* intensity of color is proportional to protein concentration
* must avoid hemolyzed blood, cannot use for urine or CSF
Biuret method for albumin quantitation
95
Increased Total Protein indicates:
* dehydration
* multiple myelom
* chronic inflammation
96
Decreased Total Protein can indicate:
* malnutrition/starvation
* hepatic insufficiency
* nephrotic syndrome
97
Total Protein < 4.5 indicates what:
```
peripheral edema
(less protein to control oncotic pressure; fluid gets into tissues)
```
98
T/F The Biuret method can be used on urine and CSF:
False. Can only be used on blood.
| Not enough protein in CSF for method to work
99
Reasons for increased protein in CSF:
* infection/inflammation of meninges
* trauma
* MS
* bloody sample
100
Reasons for decreased protein in CSF:
hyperthyroidism
101
Is protein found in urine?
Only trace amounts, most is reabsorbed by kidneys
102
Reasons for increased protein in urine:
* Nephrotic syndrome
* Multiple Myeloma
* some benign conditions
103
Normal value for globulins:
2.5 - 4.0 g/dL
104
Normal value for A/G ratio:
1.0 - 2.5
105
Globulins are divided into these 4 groups:
Alpha-1
Alpha-2
beta
gamma
106
Normal protein value for CSF:
15 - 45 mg/dL
107
What type of acute phase reactant is albumin:
negative
108
Albumin migrates the farthest and toward the ____:
anode
109
This is seen before albumin, is measured directly in lab, and can be used to monitor nutritional status:
Prealbumin
110
List the proteins associated with Alpha-1:
* antitrypsin
* fetoprotein
* lipoproteins
* acid glycoprotein
111
Increases in the Alpha-1 band are caused by:
* acute phase reaction
| * pregnancy
112
Decreases in the Alpha-1 band are caused by:
* Alpha-1 antitrypin deficiency
| * lung disease (emphysema)
113
Alpha-1 and Alpha-2 are ____ acute phase reactants:
positive
114
Albumin and Beta are ___ acute phase reactants:
Negative
115
A decrease in the Beta region can be caused by:
* acute phase reactions (negative)
* liver or renal disease
* malabsorption/malnutrition
116
List some examples of acute phase reactants:
* Alpha-1 antitrypsin
* Alpha-1 glycoprotein
* ceruloplasmin
* haptoglobin
* fibrinogen
* CRP
* Transferrin
* Albumin
117
Proteins associated with Alpha-2:
* haptolobin
* alpha-2 macroglubulin
* ceruloplasmin
118
Proteins associated with Beta:
* transferrin
* beta lipoprotein
* C3 complement
119
List the 4 non-protein Nitrogens:
Urea
Creatinine
Uric Acid
Ammonia
120
Non-protein nitrogens are products of:
protein catabolism
121
Why can we measure Urea in the blood if it is excreted in the urine:
A small amount is reabsorbed
122
Plasma concentration of urea is dependent on these two factors:
1) Diet and rate of catabolism
| 2) Renal function/profusion
123
Do we measure BUN or urea in the lab:
BUN
124
How do you convert BUN to urea:
Bun x 2.14 = Urea
125
This is defined as elevated plasma urea accompanied by renal failure:
Uremia
126
_____= elevated concentration of plasma urea:
Azotemia
127
Cause(s) of prerenal azotemia:
* CHF
* shock, hemorrhage
* dehydration
* increased protein intake
128
Cause(s) of renal azotemia:
* acute and chronic renal failure
* renal disease
* Glomerulonephritis
* Tubular necrosis
129
Cause(s) of postrenal azotemia:
*urinary tract obstruction
130
Cause(s) of decreased Urea:
* Low protein intake
* severe V/D
* Liver disease
* Pregancy
131
What are the two enzymes used in the enzymatic reacted testing for Urea:
*Urease
*GLDH
(measures change in absorbance of NADH and NAD at 340nm)
132
_____is filtered by the glomerulus, and 90-95% is excreted in urine:
Creatinine
133
This is used to asses GFR and kidney function:
Creatinine
134
Creatinine and GFR are _____ related:
Inversely
(Plasma creatinine not cleared by kidney= low GFR, high plasma creatine= creatinine not being excreted, and plasma levels will rise
135
_____is produced at a constant rate under normal conditions, in relation to muscle mass, making it an ideal measurement for GFR and renal function:
Creatinine
136
If you GFR is low, what would you expect to see in plasma creatinine level:
Increased
| creatinine is not being cleared/excreted by kidney, causing plasma levels to rise
137
Describe the Jaffe reaction, and what is it used to measure:
*Measures creatinine
*creatinine + picric acid in akaline solution= red/orange chromagen
(but many interferences)
138
How does the Kinetic Jaffe method differ from the classic Jaffe reaction:
Same as Jaffe method, but is measured in time intervals to look for change in absorbance
(accounts for interferences)
139
What can interfere with creatinine sample testing:
* ascorbic acid
* glucose
* alpha-ketoacids
* ammonia exposure
140
What is the formula for estimating GFR:
Cockcroft-Gault
(140-age) x mass
----------------------------
72 x serum creatinine
141
When would the Cockcroft-Gault formula be used:
In situations where 24 hour urine is not collected, doctor may request this
142
This can be used to determine cause of elevated BUN:
BUN/Creatinine ratio
143
Normal ratio of BUN/creatinine:
10:1 - 20:1
144
If BUN/creatinine ratio is >20:1:
* BUN is elevated, crea is normal
* Prob is is not renal or post renal, crea is being cleared
* problem would be pre-renal
145
If BUN/creatinine ratio is <10:1:
*The BUN is low, crea is normal
146
If there is a problem with the kidney itself, what will the BUN and creatinine be:
Both elevated
147
Uric acid is a product of:
purine catabolism
148
What happens when uric acid levels build up in the blood:
it will precipitate out and form crystals, which accumulate in the joints (GOUT)
149
Is high uric acid alone diagnostic of gout:
No. Other problems can cause high uric acid.
150
What is diagnostic of Gout:
Identification of Monosodium Urate crystals
151
Causes of hyperuricemia:
* Gout
* cytotoxic drugs
* renal disease
* Purine-rich diet
152
Causes of hypouricemia:
* liver disease
| * over treatment with gout and kidney stone treatment
153
What is the test methodology used for Uric Acid:
Caraway Method
| *uricase enzyme, converts uric acid to allantoin
154
What is it called when the liver converts the ammonia to urea (it is then soluble):
Ornithine cycle
155
For urea (BUN), which occurs first, transamination or deamination:
transamination
156
Which method does the Vitros use for Urea:
?
157
T/F Test samples for Urea must avoid Sodium Fluoride and ammonia:
True
158
Ammonia is a product of _____ in the liver:
deamination
159
Ammonia is found in ____ concentrations in plasma:
low
160
If liver is damaged, conversion of _____ to _____ can not occur:
ammonia
| urea
161
List the 4 steps of conversion of amino acids to urea:
1) transamination of AA's
2) deamination, forms Ammonia
3) Ornithine cycle converts ammonia to urea
4) urea to blood to kidney, most excreted, some reabsorbed (why we can measure in blood)
162
Test samples for ammonia must be handled carefully, such as:
* collect on ice
* avoid cigarette smoke
* avoid ammonia cleaning products (floor wax)
* avoid hemolysis (ammonia is still generated after draw)
163
Which method for measuring ammonia is most common on automated instruments:
GLDH enzymatic
| difference between NADH and NAD
164
Why is it important to be aware of increased ammonia levels in children under 18:
Reye's syndrome
165
T/F Reye's syndrome may occur after acute viral infections, ingestion of salicylates by children, and can lead to encephalopathy:
True
