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Biochemistry I/II > Lecture 3 and 4 > Flashcards

Lecture 3 and 4 Flashcards

1
Q

To measure analyte levels, laboratory assays most commonly use ____

A

serum

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2
Q

___:the watery acellular portion of blood separated by centrifugation of whole blood in the presence of anticoagulant

A

Plasma

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3
Q

True or False: plasma is a non-physiologic solution while serum is a physiological solution

A

False
plasma = physiological
serum = non-physiological

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4
Q

What is a major advantage of serum?

A

There are NO additives required to prevent clotting

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5
Q

True or False: plasma contains plasminogen while serum does not

A

True

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6
Q

True or False: Most diagnostically important enzymes have intracellular functions and do not normally function in blood

A

True

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7
Q

What are two reasons that a healthy person may have enzymes in their blood?

A
  1. Active secretion (i.e., coagulation precursors such as prothrombin)
  2. Release from cells at LOW LEVELS during normal cell turnover.
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8
Q

Elevated blood enzyme concentrations result when
____are damaged and intracellular enzymes are released into the blood

A

cell membranes

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9
Q

Detection of elevated enzyme levels can help to:
1)
2)
3)

A
  1. Make or confirm a diagnosis.
  2. Develop a prognosis.
  3. Monitor response to a drug therapy
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10
Q

Two clinical reasons for elevated enzymes?

A

1) Normal cell turnover
2) Pathologies

-Cellular damage, disrupts cell membranes (hepatitis, MI)
-Enzyme induction (response to metabolism of drugs)
-Physical obstructions (i.e., tumors, stones)
-Cell proliferation

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11
Q

Creatine kinase (CK or CPK) is found in the ___ and ___

Lactate dehydrogenase (LDH or LD) is found in ____, ___, ___, and ___

A

muscle and brain

liver hepatocytes, muscle, RBCs, brain

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12
Q

True or False: Both ALT/AST are found in liver hepatocytes. However, AST is also found in muscle.

A

True

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13
Q

ALK or ALP is found in the ___ and bone

Gamma glutamyltransferase GGT or GGTP is found in ___ and ___

A

Liver (hepatobiliary) and bone

Liver (biliary tree), pancreas

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14
Q

Which of these enzymes is the most specific test?

Which of these enzymes is the least specific test?

A

Most specific = ALT
Least specific = LDH

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15
Q

How might you improve diagnostic specificity?

A

Panels/profiles; isoforms

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16
Q

What is found in BMP?

hint: SPOON CCCG

A

sodium
potassium
CO2
BUN
creatine
chloride
calcium
glucose

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17
Q

Which panel is best for identifying acute problems involving kidney, diabetic shock, respiratory
distress and congestive heart failure?
A. CMP
B. BMP
C. LDH

A

B. BMP

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18
Q

Which panel is also known as Chem 7? Which panels is also known as Chem 12?

A

BMP (Chem 7); CMP (Chem 12)

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19
Q

Which panel is common for
during physical exam or to monitor chronic conditions such as HTN, DM, or monitor response to a drug regimen
that may have kidney- or liver-related adverse reactions

A

CMP

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20
Q

In addition to the tests in the BMP, CMP’s look at what other 6 substances?

A

-Albumin
-ALK/ALP
-AST
-ALT
-Total Bilirubin
-Total Protein

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21
Q

Renal profile (4) ?

A

Blood urea nitrogen (BUN)
Creatinine
BUN/Creatinine ratio
Uric Acid

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22
Q

Liver profile?

A
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23
Q

Muscle profile?

A
  • AST
  • LDH
  • CK
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24
Q

The Comprehensive Metabolic Panel includes the
Basic Metabolic Panel tests and also assesses which
of the following organs?

A. Heart
B. Pancreas
C. Liver
D. Brain

A

C. Liver

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25
Q

Which blood-derived substance does not require the addition of an anticoagulant?

A. Plasma
B. Serum

A

B. Serum

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26
Q

___: urea is a waste product of protein digestion; indicates kidney dysfunction

____:waste product of muscle contraction cleared by
kidneys; indicates kidney dysfunction.

A

BUN; Creatine

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27
Q

_____: >10:1 to 20:1 indicates poor blood flow to kidneys (i.e., congestive heart failure)

A

BUN: Creatinine

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28
Q

____: waste product of purine breakdown cleared by the kidneys; indicates hyperuricemia/gout and kidney disease

A

Uric Acid

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29
Q

In the liver profile, what three tests assess hepatocellular damage?

A

ALT:
AST:
LDH*

*=non specific

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30
Q

Which liver profile test is used to assess chronic (decreased value) vs. acute (normal) liver damage?

A

Albumin

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31
Q

In the liver profile, ___, ___, and ___ are used to assess biliary tract damage - cholestasis

A

ALP/ALK; GGT; 5 NT

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32
Q

What tests are used to identify heme degradation product diagnostic for liver function, hemolytic anemias?

A

T, D, and I BIL

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33
Q

___ is expressed in sk. and cardiac muscle and liver

A

AST

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34
Q

____ is non-specific test for muscle and heart damage

A

LDH

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35
Q

____is required for muscle cell function; after heart attack, strenuous exercise, muscle injury

A

CK

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36
Q

What is a good screening test for prostate cancer?

A

Prostate-specific antigen (PSA)

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37
Q

What 4 tests evaluate pancreatic function?

A

-Amylase
-Lipase
-Lipase:Amylase ratio (possible differentiation of alcoholic vs. non-alcoholic acute pancreatitis)
-Trypsinogen/Trypsin

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38
Q

Which elevated serum test result paired with elevated
AST levels would be the most specific diagnostic for
liver disease?

A. LDH
B. ALT
C. ALK
D. BUN

A

B. ALT

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39
Q

Which analyte is most likely to be elevated in a
patient’s serum following a heart attack?

A. CK
B. BUN
C. Creatinine
D. Amylase

A

A. CK

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40
Q

Elevated CK following a heart attack will most likely
accompany elevated…
A. Albumin
B. BUN
C. AST
D. Lipase

A

C. AST

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41
Q

____: the ability of test to actually measure what it claims to measure

___: the ability to reproducibly obtain the same result on the same patient sample.

A

Accuracy
Precision

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42
Q

The reference range is the range of values within __ SD of the mean,
which covers __% of healthy
individuals

A

2; 95%

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43
Q
A

:D

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44
Q

All isozymes of an enzyme catalyze the same reaction but differ slightly in what three ways?

A

1) Amino acid composition (often different related gene products)
2) Cell- and tissue-type in which they function
3) Timing of expression

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45
Q

Which isozyme is a tetramer composed of various combinations of H-subunits (Heart) and M-subunits (muscle)?

A

LDH Isoenzymes

46
Q

If LDH-1:LDH-2 >1, what does this indicate?

If LDH-5:LDH-4 > 1, what does this indicate?

A

HEART damage
LIVER damage

47
Q

Where is LDH-1 predominately found? Where is LDH-5 predominately found?

A

LDH-1: Heart
LDH-5: Liver

48
Q

Which isoezyme is dimer composed of 2 B-monomers (Brain), 2 M-monomers (muscle) OR one of each?

A

CK

49
Q

CK-1, found in the brain, can help diagnose ____

A

CNS damage

50
Q

Found in the myocardium, CK-2 can help diagnose ___

A

an acute MI

51
Q

Located predominately in the skeletal muscle, CK-3 can help diagnose ____

A

skeletal muscle damage

52
Q

Combination of ___and LDH-1 isozymes, along with ____ and ____ are diagnostic for AMI (acute MI)

A

CK-MB ; Troponins ; Myoglobin

53
Q

True or False: There is a Troponin I, T, and C

A

True

54
Q

While TnI, TnT, and CK-MB become elevated within 3 to 12 hours, TnI and TnT take ~5-14 days to return to normal range while CK-MB takes ___ days

A

2-3 days

55
Q

Which LDH isozyme is the most specific diagnostic test for liver damage?

A. LDH-1
B. LDH-2
C. LDH-3
D. LDH-4
E. LDH-5

A

E. LDH-5

56
Q

Which specific diagnostic test for AMI would be least sensitive for
diagnosis after 2 days post-MI?

A. LDH-1
B. CK-MB
C. Troponins

A

B. CK-MB

57
Q

____forms upon binding of substrate to the enzyme and leads to a conformation change

A

Enzyme-substrate (ES) complex

58
Q

True or False: Enzymes have catalytic efficiency and specificity

A

True

59
Q

____: non-protein molecules that enhance
enzyme activity

A

Co-factors/co-enzymes

60
Q

Zinc is an example of a ___ while NAD is an example of a ___

A

Co-factor, Co-enzyme

61
Q

____: an active enzyme associated with its non-protein component
____: inactive enzyme without its non-protein component

A

Holoenzyme; Apoenzyme

62
Q

True or False: enzymes provide a more energetically favorable path from reactants to products by lowering the activation energy barrier

A

True

63
Q

The higher the energy barrier, the ____ the reaction

A

slower

64
Q

Another name for the activation energy barrier is ____

A

free energy of activation

65
Q

___: energy difference between reactants and transition state

A

Free energy of activation

66
Q

_____: high-energy intermediate formed
prior to product formation

A

Transition state (T*)

67
Q

True or False: Enzymes ↓ free energy of activation required to reach T*

A

True

68
Q

A reaction occurs if molecules contain enough energy to overcome the energy
barrier to achieve __

A

T*

69
Q

_____ is determined by # of molecules that have sufficient
energy to overcome the barrier

A

Reaction rate or velocity

70
Q

True or False: If free energy of activation is low: more molecules have sufficient energy to reach T* AND reaction proceeds more rapidly

A

True

71
Q

The active site contains ____ groups, which contain
amino acid residues
that _____ protons

A

catalytic
donates/accepts

72
Q

True or False: hydrogen bonding promotes T state formation

A

True

73
Q

Factors influencing enzymatic reaction velocity?

A

-**substrate concentration [S]
-Temperature
-pH

74
Q

With constant [E], reaction rate increases with ↑[S] until reaching ___

A

Vmax (maximum
velocity)

75
Q

True or False: nce Vmax reached, reaction rate does increase with addition
of more substrate

A

False - NOT

76
Q

What type of curve do allosteric enzymes show?

A

Sigmoidal

77
Q

There is a ____ curve for most
enzymatic reactions

A

Hyperbolic

78
Q

MM assumptions?

A
  • [S]&raquo_space; [E]
  • rate of ES formation = rate of ES breakdown
79
Q

Km = ___ at ½ Vmax

A

[S]

80
Q

Small Km means ___ [S] needed to reach Vmax

A

Low

81
Q
A
82
Q

What type of inhibitor covalent binds to enzyme, prevents enzyme from interacting with substrate, and leads to “loss” of enzyme activity (i.e., lead poisoning)?

A

Irreversible inhibitor

83
Q

____: noncovalent binding with enzyme

A

Reversible Inhibitor

84
Q

True or False: There are competitive and non-competitive irreversible inhibitors

A

False

85
Q

What type of inhibitors compete with S to bind enzyme’s active site?

A

Competitive (reversible) Inhibitors

86
Q

What effect does a competitive inhibitor have on Vmax and Km?

A
87
Q

Statin (Pravastin) drugs inhibit rate-limiting step
in cholesterol biosynthesis and are an example of what type of inhibitor?

A

Competitive Inhibitor

88
Q

What drug competes with substrate HMG-CoA for
binding to HMG CoA-reductase?

A

Pravastin (competitive inhibitor)

89
Q

____: bind to different site than the substrate and prevent reaction from occurring –
does NOT compete with S for binding.

A

Non-competitive Inhibitors

90
Q

What two places can non-competitive inhibitors bind to?

A

Can bind to either:
1. free enzyme
2. ES complex

91
Q
A
92
Q

Penicillin, Amoxicillin inhibit bacterial cell wall synthesis and are irreversible/reversible?

A

Irreversible

93
Q

True or False: ACE inhibitors are reversible competitive inhibitors

A

True

94
Q

True or False: COX inhibitors are competitive inhibitors

A

Tru

95
Q

Aspirin is a ____inhibitor while Advil/Motron are ___, ___ inhibitor

A

irreversible ; reversible competitive

96
Q

What type of enzymes frequently catalyze the committed, rate-limiting step in a pathway?

A

Allosteric Enzymes

97
Q

What type of molecules regulate allosteric enzymes?

A

Effector molecules (bind non-cov at site other than active)

98
Q

____ effector: reduce or inhibit enzyme activity

____ effector: stimulates or increase enzyme activity

A

Negative
Positive

99
Q

True or False: Effectors can modify Vmax only

A

False - Vmax, K 0.5 or both

100
Q

Homotropic effectors are usually ___ effectors

A

positive

101
Q

Binding of substrate at allosteric site enhances activity at substrate-
binding site = ____

A

cooperativity

102
Q

Why do allosteric effectors show sigmoidal curve?

A

Sigmoidal curve because higher [S] initially
needed for reaction to proceed

103
Q

True or False: For a homotropic effector, the substrate = effector, but this is not the case with heterotropic effectors.

A

True

104
Q

An example of covalent modifications is phosphorylation of specific ___, ___, or __residues:

A

Ser, Thr, Tyr

105
Q

True or False: Phosphorylation may activate or inhibit its target enzyme

A

True

106
Q

True or False: allosteric and covalent modifications are more rapid (seconds to minutes)

A

True

107
Q

In the case of enzyme inhibition by a competitive
inhibitor, the Km will…?
A. Increase
B. Decrease
C. Not change

A

A. Increase

108
Q

In the case of enzyme inhibition by a non-competitive
inhibitor, the Vmax will…?
A. Increase
B. Decrease
C. Not change

A

B. Decrease

109
Q

Which of the following is most likely to decrease the
velocity of an enzymatic reaction?
A. Moderate rise in temperature
B. Increase in [S]
C. Binding of a positive homotropic effector
D. Extremely high or low pH

A

D. Extremely high or low pH

110
Q

Which of the following directly interferes with binding
of a substrate to an enzyme’s active site?
A. A non-competitive inhibitor
B. Binding of a heterotropic allosteric effector
C. A competitive inhibitor

A

C. A competitive inhibitor

111
Q

Which of the following is defined by the x-intercept in
a Lineweaver-Burke plot for an enzyme?
A. 1/Vmax
B. vo
C. -1/Km
D. [S]

A

C. -1/Km

Biochemistry I/II (23 decks)

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