Exam 1 (AA's, Proteins, Non-Protein Nitrogens) Flashcards Preview

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Flashcards in Exam 1 (AA's, Proteins, Non-Protein Nitrogens) Deck (165):
1

20 amino acids are divided into two groups:

Essential
Non-essential

2

How are essential amino acid supplied:

through diet when we eat proteins

3

How are non-essential amino acids supplied:

They are made from the essential amino acids, converted by liver enzymes

4

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:

transamination

5

The removal of an amino group from an amino acid; produces ammonia which is converted to urea and excreted in urine:

Deamination

6

Amino acids consist of these parts:

Amino group
Carboxyl group
Hydrogen
R-group

7

Formation of a peptide involves the ___terminal end of one amino acid reacting with the ___terminal end of another through this type of reaction:

C-terminal, N-terminal
hydrolysis reaction (H2O is released)

8

Define polypeptide:

chain of amino acids linked via peptide bonds

9

Why are amino acids zwitterions:

Amino has + charge
Carboxyl group has - charge
*net charge = 0
*makes them good buffers

10

Describe secondary peptide structure:

coiling into helix by h bonds of neighboring peptides

11

Describe tertiary peptide stucture:

Folding of peptide chain by many forces

12

The interaction of the polypeptides results in a :

protein

13

Proteins have ___ main stages of assembly:

Primary, Secondary, Tertiary, Quaternary

14

T/F All proteins contain all 20 amino acids:

False

15

When errors in metabolism occur, these can build up in blood and urine and be detected by the lab:

amino acids

16

T/F When certain amino acids accumulate in blood, they can be toxic and result in death:

True

17

What are the two categories of aminoacidopathies:

Primary
Secondary

18

Describe primary vs secondary aminoacidopathy:

*Primary: inherited defect in enzymatic pathway
*Secondary: disease of a specific organ where amino acid is synthesized (liver, kidney)

19

List the 6 Primary (inherited) amioacidopathies:

Alkaptonuria
Cystinuria ???
Homocystinuria
Maple Syrup Urine
Phenylketonuria
Tyrosinemia

20

In alkaptonuria, what enzyme is inhbitied, and what builds up:

*enzyme: homogentisic acid oxidase
*builds up: homogentisic acid

21

Which aminoacidopathy creates a buildup of homogentisic acid, causing generalized pigmentation and arthritic-like degeneration:

Alkaptonuria

22

In alkaptonuria, this will happen to urine up standing, and is caused by a buildup of what:

*urine will darken
*buildup of homogentisic acid

23

Cystinuria is not an enzymatic defect, but a defect in _____ _____:

renal absorption

24

Buildup of cysteine causes:

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