AAB Chemistry Flashcards
(190 cards)
1
Q
Which of the four elements in proteins differentiates this class of substances from carbohydrates and lipids?
A
Nitrogen
2
Q
Which of the proteins is soluble in water?
A
Albumin
3
Q
How are amino acid joined together to form a chain like structure?
A
Peptide bonding
4
Q
Proteins may become denatured when subjected to mechanical agitation, heat, or chemical treatment. What does denaturation of proteins refer to?
A
Alteration in tertiary structure
5
Q
Which aminoacodopathy is not caused by an enzyme deficiency?
A
Cystinuria
6
Q
How many immunoglobulin classes are currently recognized?
A
Five
7
Q
Which reagent is employed in the serum protein determination?
A
Biuret
8
Q
Why should hemolyzed serum not be used for total protein analysis?
A
Hemoglobin is absorbed at the same wavelength as protein in the reagent
9
Q
Which of the following is not true of the biuret reaction?
A
Is relatively free from interference by lipids and hemoglobin
10
Q
Why is bromcresol purple the preferred indicator for albumin dye binding techniques?
A
There is less interference from pigment(s)
11
Q
What is the most anodic protein on electrophoresis at pH 8.6?
A
Albumin
12
Q
A serum protein electrophoretic pattern displaying a beta gamma bridge or broad gamma is seen in which disease state?
A
Active cirrhosis
13
Q
If an electrophoretic pattern shows 30% albumin, 4%-10% alpha-globulin, 4%-10% beta-globulin, and 45% gamma-globulin, then what condition may exist in the patient?
A
Monoclonal gammopathy
14
Q
Glycoproteins and mucoproteins are usually bound to which substance?
A
Carbohydrates
15
Q
All of the following are glycoproteins except?
A. Ceruloplasmin
B. Follicle-stimulating hormone
C. Fibrinogen
D. Cryoglobulin
A
Cryoglobulin
16
Q
Which one of the following applies to cryoglobulins?
A
They are temperature-sensitive proteins
17
Q
Which of the following statements is true of albumin?
A
It is produced in the liver and it is water soluble
18
Q
Decreased alpha-fetoprotein values are associated with which condition?
A
Down syndrome
19
Q
Which one of the following proteins transports iron?
A
Transferrin
20
Q
In acute renal failure, which nonprotein nitrogen rises the fastest?
A
Blood urea nitrogen
21
Q
By the urease method, urea is enzymatically converted to which end product?
A
Ammonia
22
Q
Why can untreated urine be used for the determination of ureaby the diacetyl monoxide method?
A
The method is not measuring ammonia
23
Q
An elevated creatinine value is most likely to be accompanied by which of these values?
A
A. Normal uric acid
B. Elevated uric acid, 10X creatinine value
C. Normal blood urea nitrogen
D. Elevated blood urea nitrogen, 10X creatinine value
24
Q
What is the classical method for creatinine reaction?
A
Jaffe
25
The measurement of creatinine is based on the formation of a yellow-red color and which reagent?
Alkaline picrate
26
The creatinine clearance test is based on which assumption?
Creatinine passes into the ultrafiltrate
27
What is the most common clearance test used to measure the glomerular filtration rate?
Creatinine
28
A creatinine clearance test is performed. The 24-hour urine volume is 770mL; serum creatinine is 2.0 mg/dL and urine creatinine is 240 mg/dL. What is the clearance, assuming average body surface area?
64 mL/ minute
29
Which disease state is associated with an elevation of serum uric acid?
Gout
30
Which reagent is employed in the alkaline oxidation of uric acid?
Phosphotungstic acid
31
What does the uricase method for uric acid depend on?
Ultraviolet absorption at 290 NM before/after uricase treatment
32
Which one of the following analytes is used as a prognostic indicator for the liver failure?
A. Blood urea nitrogen
B. Ammonia
C. Uric acid
D. Cortisol
Ammonia
33
Which disaccharide is composed of two glucose molecules?
Maltose
34
What term is used to describe the process of glycogen degradation?
Glycogenolysis
35
What is the renal threshold for glucose?
160-180 mg/dL
36
Which hormone is produced by the beta cells of the islets of Langerhans?
Insulin
37
Which of the following hormones is considered a glucocorticoid?
A. Insulin
B. cortisol
C. Glucagon
D. Epinephrine
Cortisol
38
A 40 year old male has a random glucose of 470 mg/dL. This lab finding is consistent with which one of the following clinical conditions?
Diabetes mellitus
39
Which one of the following diseases is associated with hypoglycemia?
Von Gierke's disease
40
What is the specimen of choice for glucose determinations?
Fluorinated plasma
41
What is the most frequently employed automated method for glucose?
Coupled enzyme system consisting of glucose oxidase and peroxidase
42
Contamination of the glucose reagent with catalase is a problem with which glucose method?
Glucose oxidase
43
What is hexokinase methodology for glucose determination based on?
Reduced coenzyme read at 340nm
44
What is the normal fasting blood glucose reference range for adults?
70-110 mg/dL
45
Prenatal patients with borderline blood glucose levels are further evaluated by which test?
3-hour glucose tolerance test
46
Which test gives a 2- to 3- month picture of a diabetic's glucose levels?
Hemoglobin A1C
47
What does the presence of urinary ketones MOST likely indicate?
Storage lipids are being used as the primary energy source
48
Which one of the following tests is used to differentiate between inappropriate exogenous insulin administration and endogenous insulin production?
C-peptide
49
The "port wine" color of some urines can be attributed to which of the following?
Porphyrins
50
P-dimathylaminobenzaldehyde is a constituent of which reagent?
Ehrlich
51
Both porphonilinogen and urobilinogen from a red-colored compound with Ehrlich's reagent. How can they be differentiated?
Urobilinogen is soluble in chloroform
52
Prehepatic bilirubin ha which of the following for a protein carrier?
A. Albumin
B. Alpha-globulin
C. Beta-globulin
D. Gamma-globulin
Albumin
53
Direct-reacting bilirubin is also known as what substance?
Bilirubin diglucuronide
54
An increase in indirect- reacting bilirubin is suggestive of which condition?
Hemoglobin breakdown
55
Bilirubin is converted in the intestine to which of the following substances?
Urobilinogen
56
Which of the following will interfere with the Evelyn Malloy method for bilirubin?
A. Hemolysis
B. Methanol
C. Caffeine
D. Lipemia
Hemolysis
57
Which precaution should be followed in regard to specimen handling instructions for bilirubin determinations?
Protect from light
58
Which one of the following definitions best describes an enzyme?
A. Biological catalyst
B. Inorganic catalyst
C. Immunoglobulin
D. Antigenic hapten
Biological catalyst
59
Which of the following is true of an isoenzyme?
A. The rate of reaction is the same for each enzyme with is own substrate
B. The electrophoretic property is different for each isoenzyme
C. The isoenzymes react the same to chemical inhibitors
D. The substrate is different for each isoenzyme
The electrophoretic property is different for each isoenzyme
60
Why is a metal ion sometimes necessary in an enzymatic reaction?
Acts as an activator of the enzyme
61
The Michaelis-Menten constant in the rate of conversion of substrate to product is determined by what factor?
Substrate concentration and the rate of dissociation of the complex
62
In a zero-order reaction, there will be no further increase in velocity for to which one of the following?
A. There is excess enzyme
B. There is no excess substrate
C. The temperature is regulated
D. All enzyme is bound to substrate
All enzyme is bound to substrate
63
What is the reporting unit of measure for enzymes?
IU/L
64
Which enzyme catalyzes this reaction? Lactate + NAD --> pyruvate + NADH
Lactate dehydrogenase
65
Which of the following is true of the isoenzyme LD1?
It is present in the highest concentration in heart tissue
66
Which enzyme is most greatly affected by hemolysis?
Lactate dehydrogenase
67
An LD isoenzyme electrophoretic pattern that shows an increase in LD1, LD2, and LD3 is seen in which disease state?
Pernicious anemia
68
Creatine kinase is clinically significant in diseases of which organ?
Muscle
69
Creatine kinase is frequently elevated in acute myocardial infarction and which other disorder?
Duchenne's muscular dystrophy
70
Which serum enzyme begins to rise 2 to 4 hours, has peak activity occuring 12 to 36 hours, and returns to normal 2 to 4 days after an acute myocardial infarction?
Creatine kinase
71
Aspartate transaminase is elevated in all of the following conditions EXCEPT which one?
A. Myocardial infarction
B. Muscular dystrophy
C. Acute pancreatitis
D. Liver disease
Acute pancreatitis
72
Which enzyme is liver specific?
Alanine transaminase
73
Which enzyme is the most sensitive indicator of obstructive jaundice?
Alkaline dehydrogenase
74
A high alkaline phosphatase level in the presence of other negative liver function tests is indicative of which disorder?
Bone disorder
75
What is the optimum pH for acid phosphatase?
5.0
76
What is the clinical significance of an elevated acid phosphatase?
Prostatic disease
77
Which enzyme may be monitored in recovering alcoholics?
Gamma-glutamyl transferase
78
Which enzyme is characteristically elevated in mumps?
Amylase
79
Lipase catalyzes the hydrolysis of which substrate?
Triglycerides
80
What is the substrate for the cherry-crandall lipase method?
Olive oil
81
In which disease state are the highest levels of aldolase seen?
Muscular dystrophy
82
Because ionized calcium can be changed without affecting the total calcium level, what other parameter(s) must be known to properly evaluate calcium?
pH and protein
83
All of the following regulate calcium levels EXCEPT which one?
A. Vitamin D
B. Calcitonin
C. Aldosterone
D. Parathyroid hormone
Aldosterone
84
Which one of the following specimens is acceptable for the determination of total calcium?
A. EDTA plasma
B. Fluorinated plasma
C. Oxalated plasma
D. Heparinized plasma
Heparinized plasma
85
In the complexometric titration (EDTA) method for calcium, the pH must be adjusted to prevent what occurrence?
Interference by magnesium
86
The classic Clark-Collip method for calcium is based on which assumption?
Calcium will be precipitated as an oxalate
87
What is the purpose of lanthanum in the atomic absorption determination of calcium?
It will bind phosphate
88
At a pH of 7.4, most of the phosphorus in the body is in which form?
Bone
89
Inorganic phosphate can be determined from a colorimetric method involving which reagent?
Molybdate
90
A labor and delivery patient with preeclampsia is being treated for premature contractions. Which one of the following is the most likely laboratory finding?
Hypermagnesemia
91
The colorimetric method for magnesium employs which reagent?
Titan yellow
92
What is the most abundant iron-containing compound in the body?
Ferritin
93
Why should serum iron be drawn at the same time on consecutive days?
To avoid diurnal variation
94
Which protein transports the majority of copper in the bloodstream?
Ceruloplasmin
95
Increased serum copper is seen in which disease?
Wilson's disease
96
Which analytes is an early indicator of tissue hypoxia?
Lactic acid
97
What is the major extracellular cation?
Sodium
98
Which hormone acts on the distal convoluted tubule to increase sodium reabsorption?
Aldosterone
99
What is the most common method for measuring sodium?
Ion-selective electrode
100
Which one of the following is the major intracellular cation?
A. Magnesium
B. Potassium
C. Chloride
D. Sodium
Potassium
101
A potassium result of 6.8 mmol/L is obtained from a dialysis patient. Before reporting this result, what is the most appropriate action?
Check for hemolysis
102
Valinomycin can enhance the selectivity of which ISE electrode?
Potassium
103
Which of these potassium values would be termed hypokalemia?
3.0 mmol/L
104
All of the following can cause low chloride levels EXCEPT?
A. Diabetic acidosis
B. Renal failure
C. Prolonged vomiting
D. Dehydration
A. Diabetic acidosis
D. Dehydration
105
Sweat is an appropriate type of specimen for which electrolyte?
Chloride
106
In the coulometric-amperometric method for chloride, how is the amount of chloride measured?
Time needed to reach the titration end point
107
In the classes Schales-Schales (mercurimetric titration) method for chloride, what substance reacts with the indicator to form a violet color?
Excess Hg++
108
Most of the carbon dioxide in the blood is presenting which form?
Bicarbonate ion
109
All of the following specimens can be analyzed for carbon dioxide EXCEPT?
A. Urine
B. Serum
C. Plasma
D. Whole blood
Urine
110
What term describes a substance that minimizes any change in hydrogen ion concentration?
Buffer
111
Which organ primarily regulates the level of carbon dioxide?
Lung
112
What will happen if blood is exposed to air during specimen collection for pH and blood gases?
pCO2 decreases
113
Which of the following is the Henderson-Hasselbalch equation?
pH = pKa+ log (salt/acid)
114
What is the ratio of bicarbonate: carbonic acid in normal plasma?
20:1
115
Lab results on a known diabetic patient revealed a decreased bicarbonate and decreased pH. Which acid-based disorder would most likely cause these lab values?
Metabolic acidosis
116
What is the normal range for pH of blood?
7.35 - 7.45
117
Which statement concerning optical density according to Beer's law is true?
It is directly proportional to the concentration
118
For the ultraviolet range, which of these must be employed in the spectrophotometer?
Quartz cuvette
119
When performing spectrophotometer quality checks, what is the holmium oxide glass filter used to assess?
Wavelength accuracy
120
What is the principle of flame photometry?
Emission of color when an element is burned
121
What is the principle of atomic absorption spectrophotometry?
It measures light absorption of electromagnetic radiation
122
What is the light source in atomic absorption instrumentation?
Cathode lamp
123
Quenching is a disadvantage in which type of instrumentation?
Fluorometry
124
Which analytical method measures the amount of light scattered by the particles in solution?
Nephelometry
125
Which of the following is true of the pCO2 electrode?
The actual pH of the sample has no effect
126
Which one of the following statements is true concerning a protein at its isoelectric point?
A. pH of 7.0
B. Net zero charge
C. Net positive charge
D. Net negative charge
Net zero charge
127
Which statement is true concerning immuno electrophoresis?
There must be excess antibody present and constant trough distance between antibody and antigen
128
To achieve the best levels of sensitivity and specificity, a gas chromatograph may be coupled with which of the following?
Mass spectrophotometer
129
Which colligative property is most commonly used in osmometry?
Freezing point
130
The Porter-Silber reaction employs phenylhydrazine to detect which analyte?
Corticosteroids
131
The Zimmerman reaction is used to detect which analyte?
17-ketosteroids
132
Overproduction of which hormone results in acromegaly?
Growth hormone
133
Which hormone appears to function solely in the initiation and maintenance of lactation?
Prolactin
134
Which hormone acts on the renal tubules to increase water reabsorption?
Antidiuretic hormone
135
Which hormone stimulates contraction of the gravid uterus at term and also results in contraction of myoepithelial cells in the breast, causing ejection of milk?
Oxytocin
136
What is the major binding protein for thyroxine?
Thyroid-binding globulin
137
What is the T3 uptake measuring?
Thyroid-binding globulin
138
All of the following tests are good indicators of hypothyroidism EXCEPT?
T3 uptake
139
Which hormone is important in bone and calcium metabolism?
Calcitonin
140
Which hormone stimulates the renal production of vitamin D?
Parathyroid hormone
141
A low parathyroid hormone level will cause which of the following?
Low serum calcium
142
What is the hormone that controls the reabsorption of the sodium in the kidney?
Aldosterone
143
Which hormone exhibits diurnal variation?
Cortisol
144
Catecholamines are secreted by what?
Adrenal medulla
145
Which of the following is a metabolite of epinephrine?
A. Vanillylmandelic acid
B. Adrenaline
C. Dopamine
D. Serotonin
Vanillylmandelic acid
146
Which hormone is responsible for the reduction of blood sugar levels?
Insulin
147
Human chorionic gonadotropin is secreted by what?
Placenta
148
Which hormone consists of two non-identical, noncovalently bound subunits?
Human chorionic gonadotropin
149
When does the highest level of human chorionic gonadotropin occur?
First trimester
150
Which hormone is synthesized from cholesterol?
Testosterone
151
What is the urinary metabolite of serotonin?
5-hydroxyindoleacetic acid
152
Turbidity in seeing is associated with the presence of?
Chylomicrons
153
Which of these lipids had the lowest density?
Chylomicrons
154
What is the migration sequence, from the origin, of lipoproteins during electrophoresis?
Chylomicrons, beta, pre-beta, alpha
155
In which of these clinical conditions may blood cholesterol be increased?
Hypothyroidism
156
What are the regents used for color development in the Liebermann-Burchard reaction for cholesterol?
Acetic anhydride/ sulfuric acid
157
What is the purpose of the saponification step in cholesterol methods?
Convert cholesterol esters to free cholesterol
158
The enzymatic hydrolysis of triglyceride may be accomplished by what enzyme?
Lipase
159
Most triglyceride procedures involve the measurement of which end product?
Glycerol
160
Friedewald formula by which low-density lipoprotein cholesterol can be calculated.
LDL cholesterol=cholesterol - (triglycerides/5 + HDL cholesterol)
161
When calculating a coronary risk index for a patient, one must know the total cholesterol and which other parameter?
HDL cholesterol
162
Diseases of which system are associated with elevated beta lipoprotein values?
Cardiovascular
163
Which statement is true for the owl route of drug administration?
Patient compliance is not always reliable
164
Major disadvantage of drug detection by immunoassay.
Inability to simultaneously assay multiple drugs in one specimen
165
What is the method of choice for confirming drugs detected by screening methods?
Gas chromatography-mass spectrophotometry
166
THC is a metabolite of what?
Marijuana
167
Which condition is associated with a decreased CSF glucose level?
Bacterial meningitis
168
What condition is not associated with an elevated CSF total protein?
Diabetes
169
An increased CSF IgG index is characteristically seen in which condition?
Multiple sclerosis
170
Oligoclonal banding during CSF electrophoresis is characteristically seen in what condition?
Multiple sclerosis
171
When a urine specimen is allowed to stand at room temperature, which of the following does NOT occur?
A. Disappearance of formed elements
B. Elevation in pH
C. False positive glucose
D. False positive protein
False positive glucose
172
Why is the first morning specimen of urine preferred?
It contains the most formed elements
173
What plasma substance is not normally filtered through the glomerulus in significant amounts?
Protein
174
A smokey red-brown urine should be suspected of containing what?
Erythrocytes
175
A urine that turns brown-black young standing may contain?
Homogentisic acid
176
Which one of the following causes cloudiness in a freshly voided urine?
A. Protein
B. Glucose
C. White blood cells
D. Hemoglobin
White blood cells
177
What is a refractometer used to measure?
Specific gravity
178
What systems may be used to determine the specific gravity of urine
Refractometer, reagent strip test, and harmonic oscillation
179
What is the best single indicator of renal disease?
Proteinuria
180
Which of the following is true of the detection of urinary glucose?
Any reducing substance can give a glass positive reaction with the copper reduction method for Glucose
181
The prime dipstick test for occult blood depends on which fact?
Hemoglobin can act as a peroxidase
182
What type of white blood cell is seen most frequently in the urine sediment?
Neutrophil
183
A glitter cell is a term used to describe a specific type of what?
Leukocyte
184
Vaginal contamination may be responsible for the appearance of which element in the urine from a female patient?
Squamous epithelial cells
185
The matrix of urinary casts has been identified as which protein?
Tamm-Horsfall mucoprotein
186
Casts are formed primarily in which portion of the kidney?
Distal convoluted tubule
187
Which cast may appear in urine in the absence of renal disease?
Hyaline
188
A granular car is thought to represent the decomposition of which casts?
Cellular
189
What cast is seen in acute glomerulonephritis?
Red blood cell
190
Which crystal can be identified by its characteristic concentric circles?
Leucine
