BCHEM LE9 (2025) Flashcards
1
Q
- Name the numbered parts of the immunoglobulin, choose from the given choices.
What is 1 on the immunoglobulin?
A. Fc
B. Fab
C. Ag Binding
D. Light Chain
A
B. Fab
2
Q
- What is no. 2 on the image above?
A. Fc
B. Fab
C. Ag binding
D. Light Chain
A
A. Fc
3
Q
- What is no. 3 on the image above?
A. Fc
B. Fab
C. Ag Binding
D. Light Chain
A
C. Ag Binding
4
Q
- What is no. 4 on the image above?
A. Fab
B. Ag binding
C. Light Chain
D. Hinge
A
C. Light Chain
5
Q
- What is no. 5 on the image above?
A. Fab
B. Fc
C. Light Chain
D. Hinge
A
D. Hinge
6
Q
- At which portion of the electrophoretic separation of serum proteins do most immunoglobulins found?
A. alpha 1
B. alpha 2
C. beta
D. gamma
A
D. gamma
7
Q
- Which is a characteristic feature of immunoglobulins?
A. bind specifically to closely related antigens
B. each actually binds to a specific antigenic determinant
C. Antigen binding by antibodies usually result in protection of the host
D. valency of antibody refers to the number of heavy & light chains
A
B. each actually binds to a specific antigenic determinant
8
Q
- Which is an effector function of immunoglobulins?
A. in maintenance of cells
B. release of biologically inactive molecules
C. bind red blood cells
D. transfer of the immunoglobulin across the placenta
A
D. transfer of the immunoglobulin
across the placenta
9
Q
- Which is a specific product of the action of papain on immunoglobulins?
A. Fc
B. Fab
C. F(ab’)2
D. Fc peptides
A
A. Fc
10
Q
- Which of the IgGs does not fix complement?
A. IgG1
B. IgG2
C. IgG3
D. IgG4
A
D. IgG4
11
Q
- When is the J chain conferred to the immunoglobulins?
A. while being synthesized thru genetic expression
B. while being processed inside the golgi complex
C. when inside the transport vesicles from the ER to the golgi
D. upon their secretion into their site of action
A
D. upon their secretion into their site of action
12
Q
- The immunoglobulin class which is the least abundant in the normal adult is:
A. IgG
B. IgA
C. IgD
D. IgE
A
D. IgE
13
Q
- Which is characteristic feature of the light chains?
A. specific for each class of antibody
B. not specific for each class of antibody
C. reactive with antigen
D. have only a constant region
A
B. not specific for each class of antibody
14
Q
- Which is the principal immunoglobulin found in secretions such as milk?
A. IgG
B. IgM
C. IgA
D. IgE
A
C. IgA
15
Q
- Which immunoglobulin interacts with Rh antibodies?
A. IgG
B. IgA
C. IgE
D. IgD
A
A. IgG
16
Q
- When is the secretory component of IgAs synthesized?
A. made by plasma cells that secrete dimeric IgA
B. added to dimeric IgA by the M cell
C. formed by cleavage of an epithelial cell receptor used to transport the dimeric IgA across the epithelial cell
D. made by T cells
A
C. formed by cleavage of an epithelial cell receptor used to transport the dimeric IgA across the epithelial cell
17
Q
- Which of the following is function/feature of Fc fragment of IgG?
A. determines metabolic rate
B. does not bind complement
C. related to passage of IgG across the placental barrier
D. valency may be one of more depending on the type of IgG
A
C. related to passage of IgG across the placental barrier
18
Q
- Which is NOT a function/feature of IgG?
A. Major antibody in serum
B. 1st antibody produced against an
antigen during the 1’ry antibody
response
C. Activates or fixes complement
D. Involved in opsonization
A
B. 1st antibody produced against an
antigen during the 1’ry antibody
response
19
Q
- Which immunoglobulin increase in number after the initial introduction of COVID 19 virus?
A. IgM
B. IgA
C. IgE
D. IgG
A
A. IgM
20
Q
- After the COVID 19 virus has infected the host, which antibody will be predominant in the serum?
A. IgM
B. IgA
C. IgE
D. IgG
A
D. IgG
21
Q
- Where is the antigen binding site of an immunoglobulin located?
A. light chain alone
B. heavy chain alone
C. Fc region of the antibody
D. Fab regions of the antibody
A
D. Fab regions of the antibody
22
Q
- Which antibody will increase when the host develop excessive sneezing after being exposed pollen?
A. IgE
B. IgG
C. IgM
D. IgD
A
A. IgE
23
Q
- Which of the following theory of antibody production is most widely accepted?
A. Side chain theory
B. Clonal selection theory
C. Direct template theory
D. Indirect template theory
A
B. Clonal selection theory
24
Q
- Which immunoglobulin has a tail piece used for anchoring to membranes associating with Ig-alpha and Ig-beta?
A. IgE
B. IgD
C. IgM
D. IgA
A
B. IgD
25
Q
- IgE is involved in allergic reactions as a consequence of its binding to which cells?
A. red blood cells
B. Th-cells
C. mast cells
D. neutrophils
A
C. mast cells
26
Q
- When a hormone is released in the bloodstream having receptor at distant from the source is:
A. Exocrine
B. Endocrine
C. Paracrine
D. None of the above
A
B. Endocrine
27
Q
- Which hormone requires more than one organ for its production?
A. Glucagon-like peptide
B. 1,25 (OH)2-D3
C. calcitonin
D. angiotensin II
A
B. 1,25 (OH)2-D3
28
Q
- The characteristic structure of hormones derived from cholesterol includes the following:
A. 3 cyclopentane and 1 cyclohexane
B. 4 cyclopentane and 1 cyclohexane
C. 3 cyclohexane and 1 cyclopentane
D. 4 cyclohexane and 1 cyclopentane
A
C. 3 cyclohexane and 1 cyclopentane
29
Q
- What amino acid is a chemical building block that acts like a protein and sometimes like a steroid?
A. Proline
B. Tryptophan
C. Tyrosine
D. Valine
A
C. Tyrosine
30
Q
- Insulin is a glycoprotein similar to follicle-stimulating hormone, luteinizing hormone and thyroid-stimulating hormone. Their similarity lies in the:
A. Alpha subunit
B. Beta subunit
C. Delta subunit
D. All of the above
A
A. Alpha subunit
31
Q
- T3 and T4 are examples of hormones derived from ___________.
A. Amino acid derivatives
B. Polypeptides
C. Steroids
D. All of the above
A
A. Amino acid derivatives
32
Q
- Glucagon and insulin are examples of hormones derived from ____________.
A. Amino acid derivatives
B. Polypeptides
C. Steroids
D. All of the above
A
B. Polypeptides
33
Q
- A hormone can be deactivated by the following EXCEPT:
A. Changing the conformation of the receptor, so it won’t recognize the hormone
B. Dissociate the hormone-receptor complex
C. Inactivate the messenger
D. Inactivate the enzyme
A
A. Changing the conformation of the receptor, so it won’t recognize the hormone
34
Q
- What hormone is synthesized by the alpha cells in the pancreas in response to decreased plasma glucose level?
A. Epinephrine
B. Glucagon
C. Insulin
D. TSH
A
B. Glucagon
35
Q
- What hormone is synthesized by the beta cells in the pancreas in response to increased plasma glucose level?
A. Epinephrine
B. Glucagon
C. Insulin
D. TSH
A
C. Insulin
36
Q
- What is the right order to produce insulin in pancreatic cells?
A. Mature insulin→ preproinsulin →
proinsulin
B. Preproinsulin →mature insulin →
proinsulin
C. Preproinsulin → proinsulin → mature insulin
D. Proinsulin → preproinsulin → mature insulin
A
C. Preproinsulin → proinsulin → mature insulin
37
Q
- What part of the proinsulin is a connecting polypeptide with no biologic activity but is used to determine the level of insulin produced by the pancreas?
A. Alpha chain
B. Beta chain
C. C peptide
D. Signal peptide
A
C. C peptide
38
Q
- Release of the hormones norepinephrine and epinephrine from the adrenal medulla are controlled mainly by what mechanism?
A. Neuronal
B. Humoral
C. Hormonal
D. All of the above
A
A. Neuronal
39
Q
- Release of the hormones by other substances (other than hormones itself)
such as increasing glucose or calcium levels are controlled mainly by what mechanism?
A. Neuronal
B. Humoral
C. Hormonal
D. All of the above
A
B. Humoral
40
Q
- What is the function of the alpha-subunit of G-protein formed after dissociation of Gs protein?
A. The receptor to the hormone
B. The energy source for target cell
C. Stimulator of adenylate cyclase
D. Inductor of transcription
A
C. Stimulator of adenylate cyclase
41
Q
- Which hormone stimulates the activity of adenylyl cyclase?
A. Adrenaline
B. Androgen
C. Estrogen
D. Calcitriol
A
A. Adrenaline
42
Q
- What is the product of adenylate cyclase reaction?
A. cGMP
B. protein kinase A
C. cAMP
D. diacylglycerol
A
C. cAMP
43
Q
- What is the product of phospholipase C reaction?
A. diacyglycerol
B. inositol 1,4,5 triphosphate
C. CAMP
D. A and B only
A
B. inositol 1,4,5 triphosphate
44
Q
- Where is the location of the receptor for steroid hormone in a target cell?
A. Plasma Membrane
B. Cytoplasm
C. Mitochondria
D. Ribosome
A
A. Plasma Membrane
45
Q
- Where is the location of the receptor for Epinephrine in a target cell?
A. Plasma Membrane
B. Cytoplasm
C. Mitochondria
D. Ribosome
A
A. Plasma Membrane
46
Q
- What amino acid residue is considered as precursor for thyroid gland hormone formation?
A. Glycine
B. Proline
C. Tyrosine
D. Valine
A
C. Tyrosine
47
Q
- The family of steroid hormones are chemically derived from cholesterol and includes which of the following?
A. Thyroxine and triiodothyronine
B. Corticosteroids, sex hormones and vitamin D
C. Gonadotrophin-releasing hormone, growth-hormone releasing hormone
D. Growth hormone and adrenocorticotrophic hormone
A
B. Corticosteroids, sex hormones and vitamin D
48
Q
- Hormones communicate with intracellular metabolic processes through intermediary molecules called:
A. Primary messengers
B. Secondary messengers
C. Tertiary messengers
D. All of the above
A
B. Secondary messengers
49
Q
- Most hormones travel from the gland where they were produced to the tissues and cells in which they act
A. Along nerve fibers
B. Via synapses
C. In the bloodstream
D. In ducts
A
C. In the bloodstream
50
Q
- Which of the following hormones in the body would be stored and is available at week’s supply?
A. Steroids
B. Parathyroid hormone
C. Insulin
D. Thyroid hormones
A
D. Thyroid hormones
51
Q
- Inadequate intake of iodine may cause the following, EXCEPT:
A. Goiter
B. Hypothyroidism
C. Cretinism
D. Wilson’s disease
A
D. Wilson’s disease
52
Q
- Principal cation in the intracellular fluid compartment:
A. Potassium
B. Sodium
C. Copper
D. Phosphorus
A
A. Potassium
53
Q
- True of vitamin D, EXCEPT:
A. D2 is the form which is vegetable in origin
B. D3 is the form which is animal in origin
C. Rickets manifests as brittle bones due to demineralization
D. Induces intestinal and renal absorption of phosphates
A
C. Rickets manifests as brittle bones due to demineralization
54
Q
- Pernicious anemia is the classic consequence of:
A. Thiamine deficiency
B. Cobalamin deficiency
C. Pantothenic acid deficiency
D. Folic acid deficiency
A
B. Cobalamin deficiency
A. Thiamine deficiency : B1
B. Cobalamin deficiency : B12
C. Pantothenic acid deficiency : B5
D. Folic acid deficiency : B9 (macrocytic)
55
Q
- Which of the following is a biochemical indicator of pyridoxine deficiency?
A. Increased urinary excretion of cystathionine
B. Decreased urinary excretion of pyridoxic acid
C. Increased excretion of xanthurenic acid following tryptophan load
D. Decreased pyridoxal phosphate levels in the blood
E. All of the above
A
E. All of the above
56
Q
Which of the following is NOT true of
Biotin?
A. It is used as a prosthetic group in enzymatic reactions
B. Biotinidase is the enzyme that links the free carboxyl group of biotin to an enzyme
C. Prolonged intake of antibiotics decreases source of biotin
D. Avidin prevents biotin absorption because of its high affinity with biotin
A
B. Biotinidase is the enzyme that links the free carboxyl group of biotin to an enzyme
57
Q
- Which of the following is a precursor in the synthesis of CoA?
A. Niacin
B. Biotin
C. Thiamine
D. Pantothenic acid
A
D. Pantothenic acid
58
Q
- Which is NOT true of niacin?
A. Essential factor in biosynthesis of
NAD+ and NADP+
B. Has a plasma cholesterol-lowering effect
C. Deficiency of niacin causes beri-beri
D. Derived from the catabolism of tryptophan
A
C. Deficiency of niacin causes beri-beri
59
Q
- The following are macrominerals, EXCEPT:
A. Phosphorus
B. Potassium
C. Fluoride
D. Magnesium
A
C. Fluoride
60
Q
- Which of the following tend to lower both
HDL and LDL:
A. Polyunsaturated fatty acids
B. Saturated fatty acids
C. Monounsaturated fatty acids
D. Aand C only
A
A. Polyunsaturated fatty acids
61
Q
- Uses of carbohydrates in nutrition, EXCEPT:
A. Enhances fatty acid metabolism by way of the citric acid cycle
B. Dietary lactose increases the absorption of calcium
C. Decreases catabolism of amino acids
D. It decreases the use of proteins for tissue formation
A
D. It decreases the use of proteins for tissue formation
62
Q
- Factor/s increasing basal metabolic rate:
A. 2,4-dinitrophenol
B. Thyroid hormones
C. Obesity
D. Infancy
E. All of the above
A
E. All of the above
63
Q
- Specific dynamic action of food:
A. Energy used during during digestion, absorption and metabolism of food
B. Energy needed to maintain basic physiologic functions under standard conditions
C. Energy used during movement and muscle contraction
D. None of the above
A
A. Energy used during during digestion, absorption and metabolism of food
64
Q
- Basal metabolic rate:
A. Energy used during digestion, absorption and metabolism of food
B. Energy needed to maintain basic physiologic functions under standard conditions
C. Energy used for muscles and growth of body organs
D. None of the above
A
B. Energy needed to maintain basic physiologic functions under standard conditions
65
Q
- Wernicke - korsakoff syndrome:
A. Defective transketolase enzyme
B. Seen primarily in alcoholics
C. Masked chronic thiamine deficiency
D. All of the above
E. B & C only
A
D. All of the above
66
Q
- TRUE of triglycerides, EXCEPT:
A. Has a high satiety value
B. Supply essential unsaturated fatty acids
C. Serve as carriers of fat soluble vitamins
D. Provide 7 kcal/gram of energy
E. Supply body energy in the absence of other major food groups
A
D. Provide 7 kcal/gram of energy
67
Q
- Defined as the minimum daily intake of protein needed to meet the needs for normal maintenance:
A. Recommended daily dietary allowance
B. Biologic value of proteins
C. Protein requirement
D. Protein balance
E. None of the above
A
C. Protein requirement
68
Q
- Example of conditions exhibiting negative nitrogen balance, EXCEPT:
A. Pregnancy
B. Fasting
C. Debilitating diseases
D. Kwashiorkor
A
A. Pregnancy
69
Q
- Biotin is involved in which of the following types of reactions?
A. Hydroxylations
B. Carboxylations
C. Decarboxylations
D. Dehydrations
A
B. Carboxylations
70
Q
- A 3 month old boy presents with poor feeding and growth, hypotonia, lactic acidemia and mild acidosis. The pyruvate to lactate ratio is high and there is decreased conversion of pyruvate to Acetyl CoA. Which of the following may be considered for therapy?
A. Thiamine
B. FFA
C. Biotin
D. Vitamin C
A
A. Thiamine
71
Q
- Which of the following conditions would primarily produce a functional deficiency of Vitamin K?
A. Coumadin therapy
B. Broad spectrum antibiotic
C. Premature birth
D. Lack of red meat in the diet
A
A. Coumadin therapy
72
Q
- The following is/are true of dietary fiber, except:
A. Dietary fiber consists of cellulose, lignin and pectin
B. Provides approximately 7 kcal of energy from the diet
C. Adds bulk to stool
D. Can absorb 10 - 15 times its own weight in water
A
B. Provides approximately 7 kcal of energy from the diet
73
Q
- A deficiency of vitamin B12 causes:
A. Cheilosis
B. Beriberi
C. Pernicious anemia
D. Scurvy
A
C. Pernicious anemia
74
Q
- Which of the following vitamins would most likely become deficient in a person who develops a completely carnivorous lifestyle?
A. Thiamine
B. Niacin
C. Cobalamin
D. Vitamin C
A
D. Vitamin C
75
Q
- If there is a dysfunction in the oxidase enzyme system (like cytochrome oxidase, ascorbic acid oxidase), which mineral is most likely affected?
A. Zinc
B. Chloride
C. Selenium
D. Copper
A
D. Copper
76
Q
- The term used for any abnormal new growth of tissue which may be benign or malignant in nature
A. Cancer
B. Neoplasm
C. Malignancy
D. Disease
A
B. Neoplasm
77
Q
- The ability of cancer to invade and spread to other tissues
A. Metastasis
B. Angiogenesis
C. Apoptosis
D. Uncontrolled growth
A
A. Metastasis
78
Q
- These carcinogens act by introducing novel genes into normal cells
A. Radiant energy
B. Chemicals
C. Oncogenic viruses
D. None of the above
A
C. Oncogenic viruses
79
Q
- Which statement is not associated with an enhanced risk of developing skin cancer?
A. Increases with increased frequency of exposure
B. Increases with increased intensity of exposure
C. Increases with increased melanin content of skin
D. Increases depending on the time of exposure to the sun
A
C. Increases with increased melanin content of skin
80
Q
- It is estimated that 80% of human cancers are caused by these carcinogens
A. Radiant energy
B. Chemicals
C. Oncogenic viruses
D. None
A
B. Chemicals
81
Q
- Chemical carcinogens can be identified by their mutagenicity by the following assay/s
A. Ames assay
B. Lincoln assay
C. Burkitt’s assay
D. All are correct
A
A. Ames assay
82
Q
- Epstein-Barr virus is known to cause which malignancy?
A. Hepatocellular carcinoma
B. Kaposi’s sarcoma
C. Cervical carcinoma
D. Burkitt’s lymphoma
A
B. Kaposi’s sarcoma
83
Q
- These encode various proteins that drive the growth of cancer cells
A. Procarcinogen
B. Proto-oncogenes
C. Tumor suppressor genes
D. Oncogenes
A
D. Oncogenes
84
Q
- These encode proteins that normally suppress cell growth but inactivated when altered by mutations
A. Procarcinogen
B. Proto-oncogenes
C. Tumor suppressor genes
D. Oncogenes
A
C. Tumor suppressor genes
85
Q
- Also named as the “guardian of genome” and it is noted to be mutated in some 50% of human tumors
A. MYC
B. P53
C. RAS
D. RB
A
B. P53
86
Q
- Procarcinogens need to be activated by an enzyme to become which of the following?
A. True carcinogens
B. Ultimate carcinogens
C. Pre-carcinogens
D. All of the above
A
B. Ultimate carcinogens
87
Q
- A mechanism of oncogene activation where in a piece of one chromosome is split off and joined to another like in
Burkitt’s lymphoma
A. Promoter insertion
B. Chromosomal translocation
C. Gene amplification
D. Enhancer insertion
A
B. Chromosomal translocation
88
Q
- Abnormal multiplication of a gene resulting in many copies
A. Promoter insertion
B. Chromosomal translocation
C. Gene amplification
D. Enhancer insertion
A
C. Gene amplification
89
Q
- Which is not a feature of oncogenes?
A. Mutations in one of the two alleles is sufficient
B. Gain of function of a protein that signals cell division
C. Often with strong tissue preference
D. All are correct
A
C. Often with strong tissue preference
90
Q
- A family of oncogenes encoding small GTPases and they were initially identified in certain murine sarcoma viruses
A. MYC
B. P53
C. RAS
D. RB
A
C. RAS
91
Q
- A chromosomal instability wherein the chromosomal number of a cell is not a multiple of the haploid number
A. Microsatellite instability
B. Aneuploidy
C. Telomerase defect
D. Spindle assembly defect
A
B. Aneuploidy
92
Q
- A pathologic form of cell death that is not generally programmed
A. Apoptosis
B. Mutation
C. Necrosis
D. None of the above
A
C. Necrosis
93
Q
- This is the effector that digests important structural proteins and is common in both the extrinsic and intrinsic pathway of apoptosis
A. Caspase-9
B. Caspase-3
C. Caspase-8
D. APAF-1
A
B. Caspase-3
94
Q
- The stimulant of angiogenesis
A. HIF-1
B. EGF
C. VEGF
D. PDGF
A
C. VEGF
95
Q
- Calcitonin is a tumor biomarker that is associated with
A. Hepatocellular carcinoma
B. Myeloma
C. Medullary carcinoma of thyroid
D. Germ cell tumor
A
C. Medullary carcinoma of thyroid
96
Q
- Imatinib, a tyrosine kinase inhibitor, belongs to which if the following classes of drugs?
A. Inhibitors of signal transduction
B. Monoclonal antibodies
C. Inhibitors of hormone receptors
D. Anti-angiogenesis agents
A
A. Inhibitors of signal transduction
97
Q
- Cells show diminished control of growth
A. Malignant Tumors
B. Benign Tumors
C. Both
D. None
A
C. Both
98
Q
- These do not invade the local tissue nor spread to other parts of the body
A. Malignant Tumors
B. Benign Tumors
C. Both
D. None
A
B. Benign Tumors
99
Q
- Metastasis is generally responsible for the death of patients
A. Malignant Tumors
B. Benign Tumors
C. Both
D. None
A
A. Malignant Tumors
100
Q
- Proliferate rapidly and display diminished growth control
A. Malignant Tumors
B. Benign Tumors
C. Both
D. None
A
A. Malignant Tumors
