Exam 4

Question 1

Which of the following statement is/are incorrect?

a) Factor Xa catalyzes the conversion of prothrombin to thrombin.
b) Thrombin catalyzes the conversion of fibrinogen to fibrin.
c) Plasmin catalyzes the cross-linking of fibrin.
d) A & B

Answer 1

c) Plasmin catalyzes the cross-linking of fibrin.

Factor XIIIa catalyzes the cross-linking of fibrin clot

Question 2

Which of the following statements is/are incorrect?

a) The extrinsic pathway is activated by tissue thromboplastin.
b) Tissue thromboplastin is a sulfated glycosaminoglycan.
c) The intrinsic pathway is activated by contact with collagen
d) A & C

Answer 2

b) Tissue thromboplastin is a sulfated glycosaminoglycan.

The extrinsic pathway is activated by tissue thromboplastin, a lipoprotein released by damaged cells. The intrinsic pathway is activated by contact with collagen.

Question 3

Which of the following is/are incorrect?

a) Factors II, VII, IX, and X are all vitamin K independent coagulation factors
b) Functional vitamin K dependent coagulation factors all contain gamma-carboxygultamate
c) Vitamin K immediately reveres toxicity produced by warfarin
d) B & C

Answer 3

c) Vitamin K immediately reveres toxicity produced by warfarin

A should be false; Factors II, VII, IX, and X are vitamin K-dependent coagulation factors. Vitamin K allows for conversion of glutamate to gamma-carboxyglutamate in these factors. When treating warfarin toxicity, vitamin K restores capacity for synthesis of functional factors, but this will take time.

Question 4

Which of the following statements is/are incorrect?

a) A thrombus is formed in the intravascular space after death
b) Vitamin K deficiency predisposes to thrombus formation
c) Antithrombin deficiency predisposes to thrombus formation
d) A & B

Answer 4

d) A & B

A thrombus forms when coagulation factors are viable (i.e. during life). Vitamin K deficiency leads to ineffective vitamin K- dependent factors -> impaired clotting mechanism -> predisposed against thrombus formation. Antithrombin inhibits thrombus formation, thus deficiency = thrombus predisposition.

Question 5

Which of the following statements is/are incorrect?

a) Heparin is used clinically as a thrombolytic agent
b) Heparin intereferes with the final common pathway of coagulation
c) Cross-linking of fibrin renders thrombi more susceptible to thrombyolysis
d) A & C

Answer 5

d) A & C

Heparin is an anticoagulant, not a thrombolytic. Anticoagulants inhibit thrombus formation; thrombolytics dissolve the thrombus. Heparin binds plasma protein antithrombin, inducing conformational change that enhances inhibitory effect against thrombin and factor Xa. Cross-linking makes the fibrin network harder to break.

Question 6

Which of the following statements is/are incorrect?

a) The core function of the immune system is destruction of nonself molecules
b) Danger cells include cytoplasmic self proteins in the extracellular space
c) The immune system exhibits tolerance to both self and nonself molecules
d) B & C

Answer 6

a) The core function of the immune system is destruction of nonself molecules

Immune responses are directed against perceived danger. Intracellular self-molecules found in the extracellular space suggest leakage of cell contents resulting from cellular membrane damage. There is normal tolerance is toward self (i.e. self-tolerance) and some non-self (e.g. food, fetus).

Question 7

Which of the following is/are incorrect?

a) Antibodies are coded by unmodified germline DNA sequences
b) Heavy and light chains contribute to antibody class
c) Heavy and light chains contribute to binding
d) A & C

Answer 7

d) A & C

Adaptive immunity (which involves antibodies) is customized via changes in genome of lymphocytes. B should be incorrect; constant region of heavy chain determines antibody class. 
C is true; antigen-binding arm involves 1 light chain + part of 1 heavy chain.

Question 8

Which of the following is/are incorrect?

a) IgA crosses the placental barrier
b) IgG is the most abundant
c) IgM appears first
d) B & C

Answer 8

a) IgA crosses the placental barrier

IgM - 1st to appear during exposure
IgG - majority of circulating antibodies; can cross placental barrier
IgA - majority of secreted Ab in mucosal secretions and in colostrum
IgE - responds against parasitic worms; hypersensitivity and in some forms of allergy
IgD - no biological effector function yet; together with IgM, is the major membrane bound-Ig expressed by mature B-cells

Question 9

Which of the following statements is/are incorrect?

a) Lysoszymes serve to catalyse hydrolysis of bacterial cell walls
b) Cytokines and chemokines are (sorry can’t read it huhu)
c) Something about endotoxin
d) B & C

Answer 9

b) Cytokines and chemokines are (sorry can’t read it huhu)

Lysozymes catalyze hydrolysis of bacterial cell walls. Cytokines and chemokines are non-antibody proteins that regulate immune function.

Question 10

Which of the following statement/s is/are incorrect?

a) Phagocytes include neutrophils, macrophages, and monocytes
b) Activation of complement system contributes to opsonization
c) Decreased vascular permeability is a hallmark of inflammation
d) A & B

Answer 10

c) Decreased vascular permeability is a hallmark of inflammation

A and B are true. INCREASED vascular permeability is the hallmark of inflammation.

Question 11

Which of the following is/are incorrect?

a) Class I MHC molecules are normally expressed on mature human erythrocytes
b) Class I MHC molecules present fragments of endogenous antigens in most cell types
c) Class II MHC molecules typically enable recognition of antigens by T-cytotoxic cells
d) A & C

Answer 11

d) A & C

Class I MHC Molecules are found on most nucleated cells.
They enable recognition of antigens by T cytotoxic cells (e.g. for killing of virus-infected cells.
Class II MHC Molecules are found mainly on professional APCs (dendritic cell, macrophage, B cell).
They enable recognition of antigens by T helper cells.

Question 12

Which of the following is/are incorrect?

a) T-tytotoxic cells typically destroy their targets by inducing necrosis.
b) T-cytotoxic cells typically bear CD8 coreceptor for antigen recognition
c) T-helper cells typically serve to coordinate adaptive immune responses
d) B & C

Answer 12

a) T-tytotoxic cells typically destroy their targets by inducing necrosis.

T Cytotoxic Cells Typically CD8+ T cells (using CD8 as coreceptor for antigen recognition).
They may recognize and kill cells expressing specific antigens via apoptosis (induced through the action of perforins and granzymes).
T-Helper cells coordinate responses (e.g. helping B cells produce antibody).

Question 13

Which of the following is/are incorrect?

a) Active immunization entails exposure to the antigen.
b) Passive immunization is exemplified by classical vaccination
c) Passive immunization is exemplified by maternal antibody transfer
d) A & B

Answer 13

b) Passive immunization is exemplified by classical vaccination

A and C are true.
Active immunization is exemplified by classical vaccination.

Question 14

Which of the following statements is/are incorrect?

a) Blood-group antigens include MHC proteins.
b) Histocompatibility antigens include blood-group antigens.
c) Human leukocyte antigens (HLAs) are blood-group antigens.
d) A & C

Answer 14

d) A & C

Question 15

Which of the following statements is/are incorrect?

a) Th1 cells typically stimulate cell-mediated killing by T-cytotoxic cells and macrophages
b) Th2 cells typically stimulate antibody production by helping B cells
c) Th17 cells stimulates immune responses mainly against intracellular pathogens
d) B & C

Answer 15

c) Th17 cells stimulates immune responses mainly against intracellular pathogens

Should be: Th17 cells stimulates immune responses mainly against EXTRAcellular pathogens

Th1 cells secrete cytokines that stimulate cell-mediated killing by T cytotoxic cells and macrophages.
Th2 cells secrete cytokines that stimulate antibody production (by helping B cells) which tends to yield IgE (for immunity against helminthes, immediate hypersensitivity).
Th17 Cells secrete IL-17. They are involved in recruiting neutrophils and macrophages vs extracellular pathogens including bacteria and fungi especially at interface (e.g. skin, gut).

Question 16

Which of the following is/are incorrect?

a) Treg is associated with Foxp3
b) Treg typically increases during infection and decreases post infection
c) Excessive Treg suppresses protective immunity
d) A & B

Answer 16

b) Treg typically increases during infection and decreases post infection

Should be: Treg typically DECREASES during infection and INCREASES post infection

T regulatory cells (Treg) typically express Foxp3 transcriptional regulator. Their regulatory activity tends to decrease with infection and to increase after infection is cleared, avoiding excessive inflammation. They may suppress protective immunity to certain pathogens and cancer.

Question 17

Which of the following statements is/are incorrect?

a) Cross presentation enables T cytotoxic cell activation against tumors
b) Dendritic cells employ mainly class I MHC for cross-presentation
c) Endogenous antigens are recognized primarily via cross-presentation
d) A & C

Answer 17

c) Endogenous antigens are recognized primarily via cross-presentation

Should be: EXTRACELLULAR antigens are recognized primarily via cross-presentation

Cross-presentation involves presentation of epitope/s from extracellular antigen/s together with Class I MHC instead of Class I MHC. It is observed only in some APCs, especially dendritic cell (DC). It enables cytotoxic T cell activation vs virus when APC is uninfected and vs tumor/cancer.

Question 18

Which of the following statements is/are incorrect?

a) ABO blood groups are defined by the presence or absence of oligosaccharide molecules
b) Antibodies to A and B antigens are produced by persons of blood type O during normal development
c) Maternal blood type AB is a known risk factor for hemolytic anemia in fetuses of blood type O
d) B & C

Answer 18

c) Maternal blood type AB is a known risk factor for hemolytic anemia in fetuses of blood type O

Should be: Maternal blood type AB is a known risk factor for hemolytic anemia in fetuses of blood type AB

A and B are true.
In ABO hemolytic disease of the newborn, it is when the maternal blood type is O and the fetal blood type is AB that there is the risk.

Question 19

Which of the following statements is/are incorrect?

a) Degranulation is induced by crosslinking of receptor-bound IgE on mast cells.
b) Histamine is released during degranulation (exocytosis) of mast cells
c) Epinephrine acts mainly by blocking the binding of histamine to receptors
d) A & B

Answer 19

c) Epinephrine acts mainly by blocking the binding of histamine to receptors

Should be: Epinephrine acts mainly by ANTAGONIZING the binding of histamine to receptors

Epinephrine works by antagonizing the effect of histamine on its effector cells. It does not block it.

Question 20

Which of the following statements is/are incorrect?

a) Identical primary and secondary immune responses imply immunologic memory.
b) Passive immunization typically fails to induce immunologic memory.
c) Immunologic memory is typically due to proliferation of monocytes.
d) A & C

Answer 20

d) A & C

Immunological memory the ancient observation that someone who had recovered from the plague could safely care for those newly diseased.

Question 21

Which of the following changes occurs first?

a) Cessation of cell function
b) Ultrastructural changes
c) Light microscopic changes
d) Gross morphologic changes

Answer 21

a) Cessation of cell function

Question 22

Cyanide poisoning causes hypoxic cell damage through which of the following mechanisms?

a) Inability to pump out CO2 due to respiratory failure
b) Restriction of blood flow due to vasoconstriction
c) Blockage of cell enzyme action
d) Replacement of O2 from hemoglobin

Answer 22

c) Blockage of cell enzyme action

Causes of hypoxia include inadequate oxygenation due to cardiorespiratory failure, loss of blood supply or oxygen-carrying capacity of the blood due to anemia or carbon monoxide poisoning, blockage of cell enzymes as in cyanide toxicosis, and low oxygen.

Question 23

What happens in both ischemia and hypoxia?

a) Decreased blood supply due to reduced arterial flow
b) Compromised supply of glucose and other nutrients
c) Stasis of blood in compromised tissues
d) Inadequate oxygenation

Answer 23

d) Inadequate oxygenation

A to C (Decreased blood supply due to reduced arterial flow, Compromised supply of glucose and other nutrients, Stasis of blood in compromised tissues) happen only in ischemia.
D (Inadequate oxygenation) happens to BOTH ischemia and hypoxia.

Question 24

Which of the following mechanisms does not cause oxygen free radical cellular damage?

a) Direct inhibition of ATP production
b) Lipid peroxidation of membranes
c) Damage to cell proteins and enzymes
d) Fragmentation of DNA

Answer 24

a) Direct inhibition of ATP production

Main Sites of Damage in Free Radicals are lipid peroxidation of membranes, damage to proteins (peptide fragmentation), and damage to DNA (DNA fragmentation).

Question 25

Which of the following changes does not occur in cells deprived of oxygen supply? a) Shift from aerobic to anaerobic ATP production b) Increase in production of lactic acid and inorganic phosphates c) Decreased cell pH d) NOTA

Answer 25

d) NOTA All occur on cells deprived of oxygen supply. Also see the figure below.

Question 26

Which of the following is not a functional and morphologic consequence of decreased intracellular ATP during cell injury? a) Cellular swelling b) Loss of microvilli c) Clumping of nuclear chromatin d) NOTA

Answer 26

d) NOTA ER swelling, cellular swelling, loss of microvilli, blebs, clumping of nuclear chromatin, lipid deposition

Question 27

Which of the following functional and morphologic changes result from inhibition of the NaK-ATPase pump which occurs during cellular hypoxia? a) Influx and accumulation of sodium and calcium ions inside the cell b) Increased permeability to and efflux of potassium ions c) Cellular swelling d) Hyperpolarization of the cell membrane

Answer 27

d) Hyperpolarization of the cell membrane From the responses to clarifications: “The question should be NOT a result from inhibition of NaK-ATPase pump”

Question 28

Which of the following does not result from ischemia? a) Increased glycogen inside the cell b) Decreased oxidative phosphorylation c) Increased anaerobic glycolysis d) Decreased ATP

Answer 28

a) Increased glycogen inside the cell decrease O2, decrease ATP, increase cytosolic Ca++ (Cell response to stress ppt slide 34)

Question 29

Which of the following are possible targets of cell damage? a) Cell membrane integrity b) Mitochondrial function c) Genetic integrity d) Functional and structural protein e) AOTA

Answer 29

e) AOTA

Question 30

Which of the following statements is not true with regards to cell injury? a) Because of the interdependent nature of cellular systems, damage to one part may result to secondary injury to other systems b) Cell injury results from functional and biochemical abnormalities in one or more essential cellular functions c) Biochemical and morphological manifestations of injury are usually seen first before loss of cellular function occurs d) NOTA

Answer 30

c) Biochemical and morphological manifestations of injury are usually seen first before loss of cellular function occurs

Question 31

Which term refers to the cell’s ability, under physiological stresses or pathological stimuli to achieve a new steady state that would be compatible with their viability in the new environment? a) Homeostasis b) Adaptation c) Cellular Integrity d) Apoptosis

Answer 31

b) Adaptation

Question 32

Which of the following is not a major mechanism for electrical injury? a) Disruption of cell membranes and alteration of conformation of biomolecules b) Alteration of cell membrane resting potential and eliciting of muscle tetany c) Conversion of electrical energy into thermal energy d) Mechanical injury with direct trauma due to falls or violent muscle contraction e) NOTA

Answer 32

e) NOTA Major mechanisms of electricity-induced injury include direct tissue damage, disruption of cell membranes and alteration of conformation of biomolecules, alteration of cell membrane resting potential and eliciting of muscle tetany, conversion of electrical energy into thermal energy leading to massive tissue destruction and coagulation necrosis, and mechanical injury with direct trauma due to falls or violent muscle contraction.

Question 33

Injury from ionizing radiation is cause by which of the following? a) Damage to genetic material/chromosome b) Mechanical injury with direct trauma due to falls or violent muscle contraction c) Formation of crystals that puncture walls d) Direct injury to cellular structure

Answer 33

a) Damage to genetic material/chromosome a) Damage to genetic material/chromosome-> is caused by ionizing radiation. b) Mechanical injury with direct trauma due to falls or violent muscle contraction-> is electricity-induced. c) Formation of crystals that puncture walls-> is cold-induced. d) Direct injury to cellular structure-> is mechanical-induced.

Question 34

Extreme cold can cause cell damage by which of the following? a) Free radical formation and breaking of chemical bonds b) Mechanical injury with direct trauma due to falls or violent muscle contraction c) Formation of crystals that puncture cells d) Direct injury to cellular structure

Answer 34

c) Formation of crystals that puncture cells A-> is caused by ionizing radiation. B-> is electricity-induced. C-> is cold-induced. D-> is mechanical-induced.

Question 35

Mechanical trauma causes what kind of injury? a) Free radical formation and breaking of chemical bonds b) Mechanical injury with direct trauma due to falls or violent muscle contraction c) Formation of crystals that puncture cells d) Direct injury to cellular structure

Answer 35

d) Direct injury to cellular structure A-> is caused by ionizing radiation. B-> is electricity-induced. C-> is cold-induced. D-> is mechanical-induced.

Question 36

How does rheumatic fever cause cellular damage? a) Production of toxin that is harmful to cardiac cells b) Triggering an inflammatory or immune response that inadvertently injures cardiac cells c) Replication of the pneumococcal bacteria inside the myocardial cells disrupting the integrity of the cell d) Abnormal suppression of immune response to bacteria increasing vulnerability to infection

Answer 36

b) Triggering an inflammatory or immune response that inadvertently injures cardiac cells Disease from pathogenic organisms are caused by replicating inside host cell and disrupting structural integrity of cell (direct cytopathic activity, e.g. herpes virus), production of toxin harmful to host cell (e.g. clostridia and diphtheria), and triggering an inflammatory or immune response that inadvertently injures host cells (e.g. rheumatic fever, tuberculosis).

Question 37

Which of the following is an example of physiological atrophy? a) Atrophy of the thymus in adulthood b) Disuse atrophy c) Duchenne’s muscle atrophy d) Denervation atrophy

Answer 37

a) Atrophy of the thymus in adulthood Physiological atrophy is a genetically programmed “normal” decrease in size. Examples include involution of thymus gland in childhood, cessation of ova production in menopause, and aging = reduced activity.

Question 38

Which statement regarding hypertrophy is incorrect? a) It usually occurs in tissue with cells that cannot divide like muscle b) Allows the cell to achieve equilibrium between demand and function. c) Increase in cell size resulting into increase function tissue mass d) Changes are usually permanent at some point in time

Answer 38

d) Changes are usually permanent at some point in time Hypertrophy occurs in cells that cannot divide (e.g. cardiac and skeletal muscle). The number of cells remains the same, but the mass increases due to an increase in size. The 2 Causes of Hypertrophy are increased functional demand (allows the cell to achieve equilibrium between demand and function) and hormonal stimulation (e.g. estrogenic stimulation of uterine smooth muscle during pregnancy). Hypertrophy is reversible.

Question 39

Which of the following is not an example of physiologic hypertrophy? a) Muscular hypertrophy in weight lifters b) Uterine hypertrophy in pregnancy c) Left ventricular hypertrophy in hypertension d) Hypertrophy of breast tissue in lactating women

Answer 39

c) Left ventricular hypertrophy in hypertension C is pathologic.

Question 40

A person who broke his ankle had his leg in a cast for 2 months. Upon removal of the cast, his leg was noticeably smaller than his normal leg. What type of atrophy is seen in this example? a) Denervation atrophy b) Ischemic atrophy c) Disuse atrophy d) Duschenne muscle atrophy

Answer 40

c) Disuse atrophy Placement in a cast decreases workload -> disuse atrophy.

Question 41

Which of the following situations produces an example of an autoregulatory response? a) Increase in frequency and strength of uterine contractions during labor b) Decrease in heart rate as BP increases c) Contraction of urinary bladder muscle as it fills up with urine d) Vasoconstriction of the cerebral blood vessels when blood pressure rises

Answer 41

d) Vasoconstriction of the cerebral blood vessels when blood pressure rises A is due to chemical regulation. B and C are due to nervous regulation. D is autoregulation.

Question 42

Which type of body regulation responds slowly but the effect lasts for a long time? a) Neuronal regulation b) Autoregulation c) Hormonal regulation d) Renal regulation

Answer 42

c) Hormonal regulation The statement characterizes hormonal regulation (a chemical regulation). In contrast, nervous regulation is characterized by a fast response, a short duration of effect, and acts exactly or locally. Autoregulation acts independently from the other two. It has a small extent and amplitude of regulation compared to the other two types. Renal regulation is autoregulation.

Question 43

Which of the following would need an intact CNS to produce an effector response? a) Increase in HR as BP falls b) Constant blood flow to the brain over a certain range of BP c) Increase in thyroid stimulating hormone levels when thyroid hormone levels decrease d) Vasoconstriction of the afferent arteriole during exercise

Answer 43

a) Increase in HR as BP falls A is governed by nervous regulation. B and D are governed by autoregulation. C is governed by chemical regulation.

Question 44

Which of the following is a part of the negative feedback loop? a) Liver stores glucose as glycogen in the presence of hyperglycemia b) Uterine contractions become more frequent and stronger near childbirth c) Inhibition of micturition despite the conscious desire to void d) Decrease in heart rate causing a syncopal attack

Answer 44

a) Liver stores glucose as glycogen in the presence of hyperglycemia

Question 45

Which of the following has a low-pressure baroreceptor? a) Cardiac atrium b) Aortic sinus c) Carotid sinus d) Renal Artery

Answer 45

a) Cardiac atrium B and C are high pressure baroreceptors. D has an internal baroreceptor mechanism.

Question 46

How many liters is the appropriate plasma volume for a 70kg male? a) 40.0 b) 10.5 c) 7.5 d) 3.5

Answer 46

d) 3.5 70 kg x 0.05 = 3.5 Intracellular Fluid is 40% of body weight Extracellular Fluid: Interstitial fluid is 15% of body weight plasma volume is 5% of body weight(kg).

Question 47

To preserve intravascular volume, the kidneys will preserve which of the following? a) Water b) Urea c) Sodium d) Potassium

Answer 47

c) Sodium

Question 48

Which of the following is an/are absolute requirement(s) for osmosis? a) Presence of permeant solutes b) Aquaporins or H2O channels c) Presence of transmembrane osmotic gradient d) Semipermeable membrane

Answer 48

c) Presence of transmembrane osmotic gradient A and B are not necessary. Between C and D, C is the absolute requirement.

Question 49

What happens when a cell is placed in a solution containing permeant solute? a) The cell initially shrinks then swells b) The cell initially swells then shrinks c) The cell initially shrinks then returns to original volume d) The cell initially swells then returns to its original volume

Answer 49

c) The cell initially shrinks then returns to original volume

Question 50

Which of the following changes happens when one drinks sea water? a) Increase in intravascular volume b) Decrease in interstitial volume c) Increase in intracellular volume d) Decrease in intravascular volume

Answer 50

a) Increase in intravascular volume Seawater introduces higher salt levels to the bloodstream. Water rushes into the blood stream, leading to an increase in intravascular volume, an increase in interstitial volume, and a decrease in intracellular volume.

Question 51

You have heard of stories how a person lose in the wilderness without access to water survives because he drank his urine. What is the possible explanation? a) There is an increase in blood pressure because of an increase in intravascular volume b) Drinking will make the kidneys conserve water c) Plasma osmolarity decreases as one drinks his own urine and fluid is redistributed throughout the body compartment d) Substances in the urine can increase peripheral vascular resistance, which can improve the blood pressure

Answer 51

a) There is an increase in blood pressure because of an increase in intravascular volume

Question 52

What will be the results of an osmolarity study of a 36-year old male who just donated 500 mL of blood? a) Serum: 285 mosm/L, urine: 100 mosm/L b) Serum: 250 mosm/L, urine: 100 mosm/L c) Serum: 285 mosm/L, urine: 600 mosm/L d) Serum: 310 mosm/L, urine: 600 mosm/L

Answer 52

c) Serum: 285 mosm/L, urine: 600 mosm/L Blood loss -> increased osmolarity of blood and urine.

Question 53

What will be the osmolarity study of a 17 year old after drinking 2 liters of water for an ultrasound? a) Serum 275, urine 50 mosm/L b) Serum 285, urine 285 mosm/L c) Serum 220, urine 600 mosm/L d) Serum 255, urine 300 mosm/L

Answer 53

a) Serum 275, urine 50 mosm/L Drinking water -> decreased osmolarity of blood and urine.

Question 54

What will be the results of an osmolarity study of an 18 year old male who had just finished a military drill? a) Serum: 285 mmosm/L, urine: 100 mosm/L b) Serume: 250; Urine: 100 c) Serum: 290; Urine: 600 d) Serume: 315; Urine; 600

Answer 54

c) Serum: 290; Urine: 600 Exercise -> water loss -> increased osmolarity of blood and urine.

Question 55

What happens to the intracellular fluid after blood donation? a) Increase b) Decrease c) NO change d) Any of the above changes can happen

Answer 55

c) NO change

Question 56

Function of intermediate filaments? a) Provide tracks for cell movement b) Allow cell crawling c) Withstand mechanical stress due to stretch d) Position organelles

Answer 56

c) Withstand mechanical stress due to stretch A, B and D are functions of microtubules.

Question 57

Which is the toughest and most durable of the three types of cytoskeletal filaments? a) Intermediate filaments b) Microtubules c) Actin filaments d) All are tough and durable

Answer 57

a) Intermediate filaments Intermediate filaments serve to withstand mechanical stress.

Question 58

Intermediate filaments are found in what structures? a) The mitotic spindles b) Centromeres c) Desmosomes (Not sure if this is what the answer key says) d) Cilia

Answer 58

c) Desmosomes (Not sure if this is what the answer key says) A, B and D contain microtubules.

Question 59

Which of the following cytoskeletal structures provides tracks for guiding intracellular transport? a) Intermediate filaments b) Microtubules c) Actin Filaments d) Neurofilaments

Answer 59

b) Microtubules - Provide tracks for cell movement - Allow cell crawling - Position organelles

Question 60

Kinesin and Dynein both each use the energy of ____ to power movement ___ along microtubules. a) ATP Hydrolysis; in a single direction b) ATP Hydrolysis; in both directions c) GTP Hydrolysis; in a single direction d) GTP Hydrolysis; in both directions

Answer 60

a) ATP Hydrolysis; in a single direction There is use the energy of ATP hydrolysis to move along microtubules and actin. Along microtubules, vesicles with plus-end-directed kinesin attached move outward, and vesicles with minus-end directed dynein attached move inward. +end kinesin -> outward -end kinesin -> inward

Question 61

In a eukaryotic flagellum, which of the following drives the bending of microtubules? a) Basal Body b) Motor protein ciliary dynein c) Fluid that surrounds the flagellum d) Actin and Myosin

Answer 61

b) Motor protein ciliary dynein The basal body holds the flagellum in place. Actin and myosin are not involved in microtubule bending.

Question 62

Cell crawling depends on which of the following processes? a) Actin polymerization b) Microtubule assembly c) Hydrolysis of ADP by motor proteins d) Intermediate filaments

Answer 62

a) Actin polymerization Cell crawling depends on microtubules.

Question 63

In which of the following cell/cells is Myosin-I present? a) Nerve cells only b) Muscle cells only c) Epithelial cells only d) All types of cells

Answer 63

d) All types of cells

Question 64

Myosins are motor proteins that use the energy of ATP hydrolysis to move along actin filaments? a) False b) True

Answer 64

b) True

Question 65

Which does not contin actin and myosin? a) Muscle cell sarcomere b) The contractile ring that carries out cytokinesis c) The filopodium at the leading edge of a crawling cell d) A contractile bundle in a non-muscle cell

Answer 65

c) The filopodium at the leading edge of a crawling cell Cellular crawling involves mictrotubules which contain tubulin.

Question 66

Which of the following is true of necrosis? a) Cellular swelling b) Nuclear shrinkage c) Require ATP d) Involvement of cytochrome c

Answer 66

a) Cellular swelling B, C & D are characteristic of apoptosis.

Question 67

Which of the following is true about apoptosis? a) Presence of inflammation b) Cause by chemical injury c) Cleared by phagocytosis d) Cellular leakage

Answer 67

c) Cleared by phagocytosis A, B & D are characteristic of necrosis.

Question 68

Which of the following is not a means of controlling CDKs? a) Phosphorylation b) DNAse activation c) Binding by inhibitors d) Amount of cyclins

Answer 68

b) DNAse activation CDK’s are proteins and are not directly affected by DNAases.

Question 69

Which of the following is not a cell cycle checkpoint? a) G1 to S transition b) S phase c) G2 to M transition d) Anaphase to Telophase transition

Answer 69

d) Anaphase to Telophase transition Based on the figure below, all seem to be cell cycle checkpoints. However, based on the lecture, the cell cycle checkpoints are G1, G2, and the spindle assembly checkpoint. The answer should be B.

Question 70

Which of the following is the S phase cyclin? a) Cyclin A b) Cyclin B c) Cyclin D d) Cyclin E

Answer 70

a) Cyclin A According to Dr. Medina "Generally starts or increases in G1 or S-phase but never in G2."

Question 71

Which of the following binds to CDK to form MPF? a) Cycling A b) Cyclin B c) Cyclin D d) Cyclin E

Answer 71

b) Cyclin B Cyclin B is the mitotic cyclin which functions in entry to M-phase. It binds CDK1 to make MPF (maturation promoting factor).

Question 72

Which of the following is an effector of apoptosis? a) Bcl-2 family b) Cytochrome C c) Caspase d) p53

Answer 72

c) Caspase

Question 73

Which of the following signals does not promote apoptosis? a) Fas Ligand b) TNF alpha c) TNF beta d) Interleukin-2 (IL-2)

Answer 73

d) Interleukin-2 (IL-2) Withdrawal of ppositive signals: - growth factors for neurons - Interleukin-2 (IL-2) Death activators: - tumor necrosis factor alpha (TNF-alpha) - lymphotoxin (TNF-beta) - fas ligand (FasL)

Question 74

Which of the following doesn’t occur in apoptosis? a) Restore mitochondrial membrane b) Post-transcriptional cleave of procaspases c) Mitochondrial release of stored cytochrome c d) Breakdown of brain proteins

Answer 74

a) Restore mitochondrial membrane In apoptosis, these activities take place: occupation of death receptors, dimerization of Bcl-2 family members, release of cytochrome c, activation of caspases, activation of DNase. Mitochondrial permeability transition (not restoration) leads to release of cytochrome c; breakdown of brain proteins occurs due to caspases.

Question 75

Which of the following molecular event bridges the extrinsic and intrinsic pathways of apoptosis? a) Formation of the apoptoisome b) Truncation of Bid to tBid c) Association of the Bad protein with the Bcl-2 members d) Activation of Caspase 9

Answer 75

b) Truncation of Bid to tBid

Question 76

Which is least likely to result in uncontrolled cell division? a) Mutation in both tumor suppressor alleles b) Oncogene that is always active c) Deletion of a proto-concogene gene d) An inhibition-resistant tumor suppressor protein

Answer 76

c) Deletion of a proto-concogene gene A, B, and D will lead to uncontrolled cell division.

Question 77

Which cell stage is most sensitive to oncogene activity? a) G1 b) S c) G2 d) M

Answer 77

a) G1 It is the stage which determines commitment to go through the cell cycle.

Question 78

Which cell cycle stage determines commitment to go through the cell cycle? (R Point) a) G1 b) S c) G2 d) M

Answer 78

a) G1 G1 is the restriction point. It is largely dependent on nutrient availability and often cell size (cells wont divide if too small).

Question 79

Which of the following will result from non-polyubiquitination of cyclin B? a) Uncontrolled continuous nuclear division b) Non-entry to the M phase c) Exit out of the cell cycle to G0 d) Arrest of nuclear division

Answer 79

d) Arrest of nuclear division Non-polyubiquitination will cause high MPF levels to remain. Since MPF’s promote entrance into mitosis, isn’t the answer A?

Question 80

Which of the following is a feature of the early divisions of embryonic cells? a) No G1 and G2 b) No G1, Short G2 c) Short G1, no G2 d) Short G1 and G2

Answer 80

b) No G1, Short G2 In embryonic cells, cell growth not part of cell cycle. All energy goes to DNA synthesis so G1 lacking and G2 quite short. Each round of division subdivides original cytoplasm into smaller and smaller cells until adult cellular size is reached.

Question 81

In cancer, which cell cycle stage is responsible for insensitivity to growth inhibition? a) G1 b) S c) G2 d) M

Answer 81

a) G1 In cancer cells, G1 is short. Also remember that G1 is the stage which determines commitment to go through the cell cycle.

Question 82

Which of the following is not true about cytokinesis? a) Involves actin b) Highly dependent on ATP c) Involves microtubules d) Initiates after mitosis

Answer 82

d) Initiates after mitosis Cytokinesis is able to proceed simultaneously with telophase.

Question 83

Which of the following mechanisms does p21 render CDKs non-functional? a) Proteolytic cleavage of CDKs b) Phosphorylation of CDKs c) Blockage of substrate binding to CDKs d) Displacement of cyclin to CDKs

Answer 83

c) Blockage of substrate binding to CDKs

Question 84

What will be the cellular outcome when there is a longer persistence of activated CDKs during G1? a) Shorter G2 length b) Hypertrophic cell c) G1 arrest d) Smaller cell volume

Answer 84

b) Hypertrophic cell Persistence of active CDK’s is similar to the effect of the situation in #79.

Question 85

What is true about interphase? a) Dependent on 1 type of cyclin b) Metabolically less active than G0 c) Cell size is fixed d) Chromosome number is not constant

Answer 85

d) Chromosome number is not constant Chromosome number doubles during G2 phase.

Question 86

In Rh incompatibility during pregnancy, which of the following statements is true? a) Rh antigens are only expressed in the RBCs of the infant b) Rh antigens are only expressed in the skin cells of the infant c) Rh antigens are only expressed in the outermost cell layer of the placenta d) Rh antigens are only expressed in the blood of the mother

Answer 86

a) Rh antigens are only expressed in the RBCs of the infant In Rh incompatibility, the mother is Rh negative and the child is Rh positive. Rh antigens are expressed only on the surface of red blood cells.

Question 87

Accumulation of which of the following directly results in the jaundice characteristic of the hemolytic disease of the newborn: a) Hemoglobin b) RhD Protein c) Bilirubin d) D antigen

Answer 87

c) Bilirubin Bilirubin is a byproduct of hemoglobin catabolism. It is yellow and it is responsible for jaundice in hemolytic disease of the newborn.

Question 88

Which of the following statements is incorrect? a) An individual who is Rh+ can receive Rh+ blood b) An individual who is Rh- can receive Rh+ blood c) An individual who is Rh+ can receive Rh- blood d) An individual who is Rh- can receive Rh- blood

Answer 88

b) An individual who is Rh- can receive Rh+ blood An Rh negative individual will produce anti-Rh antibodies against Rh positive blood.

Question 89

hoGAM is an anti D immune globulin. Which of the following best describes its mechanism of action? a) Agglutinzation of fetal RBC in mother’s blood, which is then excreted from mother’s body b) Prevention of formation of Anti D antibodies by the mother c) Triggers production of more antibodies targeting D-antigen d) Neutralization of D-antigen by removal of epitopes leading to loss of immunogenicity

Answer 89

b) Prevention of formation of Anti D antibodies by the mother RhoGAM is a solution of IgG anti-D (anti-RhD) antibodies that take out any fetal RhD-positive erythrocytes which have entered the maternal blood stream from fetal circulation, before maternal immune system can react to them, thus preventing maternal sensitization.

Question 90

Which of the following statements is/are correct? a) Rh blood group is classified based on the presence of the D antigen b) Rh blood group is classified based on the presence of C and c antigen c) Rh blood group is classified based on the presence of E and e antigen d) AOTA

Answer 90

a) Rh blood group is classified based on the presence of the D antigen Rh positive and Rh negative describe the presence or absence of the D antigen.

Question 91

What is the probability of a child with an Rh-negative mother and a heterozygous Rh-positive father to develop ____ in the newborn. a) 100% b) 75% c) 50% d) 25%

Answer 91

c) 50% Treat the RhD gene as if it were autosomal dominant. Hence in this scenario, dd x Dd. However, bear in mind that there is no d allele (it is simply the absence of the D allele).

Question 92

Which is not a symptom of hemolytic disease in a newborn? a) Anemia b) Fluid buildup c) Production and release of immature RBC d) AOTA

Answer 92

d) AOTA All should be symptoms. A is a direct consequence of the hemolytic disease. B is the manifestation of Hydrops fetalis, while C is the manifestation of Erythroblastosis fetalis, both consequences of hemolytic disease of the newborn.

Question 93

Which of the following best describes why firstborn infants are often not affected by Rh incompatibility? a) Fetal red blood cells rarely cross the placenta during the pregnancy b) It takes time for anti-D antibodies to develop in the mother

Answer 93

b) It takes time for anti-D antibodies to develop in the mother

Question 94

Which of the following statements about pulmonary embolism (PE) during pregnancy is true? a) PE during pregnancy is a catastrophic but infrequent cause of death of pregnant patients b) PE during pregnancy is a rare cause of death if it occurs because it is easily reversible c) PE occurs just as frequently in pregnant and non-pregnant patients d) NOTA

Answer 94

d) NOTA

Question 95

Which of the following should be included in the strategies to address PE during pregnancy? a) Widespread use of appropriate prophylaxis b) Early detection of venous thromboembolism (VTE), which predisposes to PE c) Prompt, safe, and effective therapy for PE when it occurs d) AOTA

Answer 95

d) AOTA

Question 96

Which of the following explains the increased predisposition to PE during pregnancy? a) Increased amount of clotting factors b) Venous stasis aggravated by destruction of venous drainage by the enlarging uterus c) Decreased fibrinolysis d) AOTA

Answer 96

d) AOTA

Question 97

Which of the following are important risk factors to develop PE during pregnancy? a) Previous idiopathic VTE (while not pregnant) b) VTE that occurred during a previous pregnancy c) Patients with a positive family history d) AOTA

Answer 97

d) AOTA

Question 98

Which of the following describes appropriate management of PE during pregnancy? a) Confinement in bed in predisposed patients in order to decrease clotting factor production b) Use of anticoagulants that are safe for the fetus c) Early delivery when fetus becomes viable d) Wearing abdominal support as the uterus enlarges

Answer 98

b) Use of anticoagulants that are safe for the fetus

Question 99

Pregnancy is a hypercoagulable state, which results from which of the following? a) Increase in procoagulant factors b) Increase in anti-coagulant activity c) Increase in fibrinolytic activity d) A & C

Answer 99

a) Increase in procoagulant factors

Question 100

Treatment of PE during pregnancy a) Thrombin b) Heparin c) Warfarin d) NOTA

Answer 100

b) Heparin Thrombin promotes thrombus formation and will aggravate pulmonary embolism. Between heparin and warfarin, warfarin is contraindicated for pregnant women. So the answer is B.