Q.1 Which protein is the most abundant component of the extracellular matrix in connective tissues?
Collagen
Fibronectin
Laminin
Elastin
Explanation - Collagen accounts for about 70–80% of the dry weight of the extracellular matrix, making it the most abundant structural protein in connective tissues.
Correct answer is: Collagen
Q.2 What is the primary role of proteoglycans in the extracellular matrix?
Provide electrical conductivity
Store calcium ions
Regulate cell adhesion
Retain water and provide compressive resistance
Explanation - Proteoglycans have glycosaminoglycan (GAG) chains that attract water, giving tissues like cartilage the ability to withstand compression.
Correct answer is: Retain water and provide compressive resistance
Q.3 Which enzyme family is mainly responsible for degrading collagen in the extracellular matrix?
Matrix metalloproteinases (MMPs)
Serine proteases
Cysteine proteases
Lysyl oxidases
Explanation - MMPs, particularly MMP-1 (collagenase), cleave the triple helix of collagen, facilitating ECM remodeling.
Correct answer is: Matrix metalloproteinases (MMPs)
Q.4 Which extracellular matrix protein serves as a ligand for integrin receptors to mediate cell attachment?
Collagen
Fibronectin
Elastin
Perlecan
Explanation - Fibronectin contains RGD sequences recognized by integrins, allowing cells to adhere to and migrate within the matrix.
Correct answer is: Fibronectin
Q.5 What does the abbreviation 'GAG' stand for in the context of extracellular matrix components?
Glycosylated Acidic Glycoprotein
Glycosaminoglycan
Glutamic Acid Glycine
Glycine-Alanine-Glycine
Explanation - GAGs are long, unbranched polysaccharides that carry a negative charge and are attached to core proteins to form proteoglycans.
Correct answer is: Glycosaminoglycan
Q.6 Which structural protein provides elasticity to blood vessels and skin?
Collagen
Elastin
Fibronectin
Laminin
Explanation - Elastin forms elastic fibers that allow tissues such as blood vessels to recoil after stretching.
Correct answer is: Elastin
Q.7 Which signaling molecule is released by fibroblasts to stimulate collagen synthesis during wound healing?
Transforming Growth Factor-beta (TGF-β)
Insulin
Epidermal Growth Factor (EGF)
Adrenaline
Explanation - TGF-β is a key cytokine that promotes fibroblast proliferation and collagen deposition in the ECM during repair.
Correct answer is: Transforming Growth Factor-beta (TGF-β)
Q.8 Which of the following is NOT a function of the extracellular matrix?
Provide mechanical support
Facilitate cell signaling
Serve as a storage depot for growth factors
Conduct electrical impulses across tissues
Explanation - While ECM supports structural and signaling roles, electrical conduction is mediated by cells, not the ECM itself.
Correct answer is: Conduct electrical impulses across tissues
Q.9 What is the main crosslinking enzyme that stabilizes collagen fibers in the ECM?
Lysyl oxidase
Matrix metalloproteinase
Fibronectin
Integrin
Explanation - Lysyl oxidase catalyzes covalent crosslink formation between lysine residues, strengthening collagen and elastin fibers.
Correct answer is: Lysyl oxidase
Q.10 Which type of ECM remodeling involves the removal of old or damaged matrix components?
Matrix deposition
Matrix degradation
Matrix mineralization
Matrix synthesis
Explanation - Matrix degradation is carried out by enzymes like MMPs to clear space for new matrix deposition.
Correct answer is: Matrix degradation
Q.11 In tissue engineering, what property of a scaffold is most important for supporting cell adhesion?
Electrical conductivity
Hydrophilicity and presence of RGD motifs
Thermal conductivity
Magnetic permeability
Explanation - Scaffolds with hydrophilic surfaces and RGD peptides encourage integrin-mediated cell attachment.
Correct answer is: Hydrophilicity and presence of RGD motifs
Q.12 Which component of the ECM is primarily responsible for binding and presenting growth factors to cells?
Elastin
Collagen
Proteoglycans
Laminin
Explanation - The highly negative GAG chains of proteoglycans trap growth factors, regulating their local concentration.
Correct answer is: Proteoglycans
Q.13 What is the main difference between type I and type III collagen in terms of tissue distribution?
Type I is found only in bone, while type III is found only in skin
Type I is more abundant in dermis and bone; type III is abundant in skin and blood vessels
Type I is elastic; type III is rigid
Type I is synthesized by fibroblasts; type III by osteoblasts
Explanation - Type I collagen provides tensile strength, whereas type III provides elasticity in tissues like skin and vessels.
Correct answer is: Type I is more abundant in dermis and bone; type III is abundant in skin and blood vessels
Q.14 Which of the following is an example of a glycoprotein found in the basement membrane?
Fibronectin
Elastin
Laminin
Collagen Type IV
Explanation - Laminin is a key glycoprotein of basement membranes that organizes other components and interacts with cells.
Correct answer is: Laminin
Q.15 What role does the enzyme tissue inhibitor of metalloproteinase (TIMP) play in ECM remodeling?
Activates collagen synthesis
Inhibits MMP activity to prevent excessive matrix degradation
Crosslinks elastin fibers
Degrades proteoglycans
Explanation - TIMPs regulate MMPs, ensuring balanced ECM turnover and preventing tissue damage.
Correct answer is: Inhibits MMP activity to prevent excessive matrix degradation
Q.16 Which cell type is primarily responsible for producing ECM components during tissue repair?
Neurons
Fibroblasts
Red blood cells
Lymphocytes
Explanation - Fibroblasts synthesize collagen, proteoglycans, and other matrix molecules in the wound healing process.
Correct answer is: Fibroblasts
Q.17 Which property of an extracellular matrix component directly affects tissue stiffness?
Its glycosylation pattern
Its crosslinking density
Its molecular weight
Its charge density
Explanation - Higher crosslinking (e.g., via lysyl oxidase) increases matrix rigidity, influencing cell mechanotransduction.
Correct answer is: Its crosslinking density
Q.18 What is the main function of fibronectin in the wound healing process?
Act as an antioxidant
Serve as a scaffold for cell migration
Store calcium ions
Trigger apoptosis in fibroblasts
Explanation - Fibronectin fibers create a matrix that cells migrate on, facilitating tissue repair.
Correct answer is: Serve as a scaffold for cell migration
Q.19 Which of the following is a major component of the basement membrane?
Collagen Type I
Elastin
Collagen Type IV
Laminin
Explanation - Collagen Type IV forms a network within basement membranes, providing structural support.
Correct answer is: Collagen Type IV
Q.20 What is the role of hyaluronic acid in the extracellular matrix?
Provides tensile strength
Acts as a scaffold for cell adhesion
Retains water and contributes to tissue hydration
Crosslinks collagen fibers
Explanation - Hyaluronic acid attracts water, keeping tissues hydrated and pliable.
Correct answer is: Retains water and contributes to tissue hydration
Q.21 Which type of ECM component is most abundant in cartilage?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Cartilage is rich in collagen Type II, providing compressive resistance.
Correct answer is: Collagen Type II
Q.22 How does the extracellular matrix influence stem cell differentiation?
By altering the genome sequence
By providing mechanical cues and binding growth factors
By secreting neurotransmitters
By changing cell membrane potential only
Explanation - ECM stiffness and bound signals guide stem cells toward specific lineages.
Correct answer is: By providing mechanical cues and binding growth factors
Q.23 Which of the following enzymes is NOT involved in ECM remodeling?
Matrix metalloproteinase (MMP)
Lysyl oxidase
DNA polymerase
Tissue inhibitor of metalloproteinase (TIMP)
Explanation - DNA polymerase is involved in DNA replication, not ECM remodeling.
Correct answer is: DNA polymerase
Q.24 What is the primary role of elastin in the extracellular matrix?
Providing tensile strength to bone
Enabling elastic recoil in tissues like arteries
Binding growth factors
Crosslinking proteoglycans
Explanation - Elastin fibers allow tissues to stretch and return to their original shape.
Correct answer is: Enabling elastic recoil in tissues like arteries
Q.25 Which extracellular matrix component is directly involved in forming the structural network within the basement membrane?
Collagen Type III
Collagen Type IV
Collagen Type I
Fibronectin
Explanation - Collagen Type IV assembles into a scaffold that supports the basement membrane.
Correct answer is: Collagen Type IV
Q.26 Which factor does NOT contribute to the mechanical properties of the extracellular matrix?
Crosslink density
Proteoglycan concentration
Cell membrane potential
Collagen fiber alignment
Explanation - The cell membrane potential is unrelated to ECM mechanical characteristics.
Correct answer is: Cell membrane potential
Q.27 What is the main function of fibronectin in cell migration?
Inhibits integrin signaling
Provides a scaffold for cell movement
Crosslinks collagen fibers
Sequesters calcium ions
Explanation - Fibronectin fibers guide cells during migration and wound closure.
Correct answer is: Provides a scaffold for cell movement
Q.28 Which of the following best describes the interaction between integrins and ECM proteins?
Integrins act as enzymes to degrade ECM
Integrins bind ECM proteins to transmit mechanical signals
Integrins are ECM proteins that provide structure
Integrins are cell membrane ion channels unrelated to ECM
Explanation - Integrins are transmembrane receptors that sense ECM composition and stiffness.
Correct answer is: Integrins bind ECM proteins to transmit mechanical signals
Q.29 What is the main difference between fibrous and gel-like ECM components?
Fibrous are rigid, gels are flexible
Fibrous contain collagen, gels contain hyaluronic acid
Fibrous provide mechanical strength, gels provide hydration
Fibrous are produced by fibroblasts, gels by osteoblasts
Explanation - Fibrous proteins like collagen create a scaffold; gels like proteoglycans retain water.
Correct answer is: Fibrous provide mechanical strength, gels provide hydration
Q.30 Which cell surface receptor is primarily responsible for binding to the RGD motif of fibronectin?
EGFR
Integrin α5β1
TNF receptor
Insulin receptor
Explanation - Integrin α5β1 recognizes RGD sequences on fibronectin, mediating cell adhesion.
Correct answer is: Integrin α5β1
Q.31 What is the main function of the extracellular matrix in bone?
Serve as electrical insulator
Provide structural framework and store minerals
Generate heat
Produce neurotransmitters
Explanation - Bone ECM is rich in collagen and mineralized to support weight and load.
Correct answer is: Provide structural framework and store minerals
Q.32 Which molecule is responsible for crosslinking collagen fibers in the ECM?
Fibronectin
Lysyl oxidase
Proteoglycan
Integrin
Explanation - Lysyl oxidase catalyzes covalent crosslinks between lysine residues in collagen.
Correct answer is: Lysyl oxidase
Q.33 What role does the extracellular matrix play in nerve regeneration?
Inhibits axon growth
Provides a scaffold for axon extension and binds growth factors
Generates electrical signals
Creates magnetic fields
Explanation - ECM components like laminin support neuronal migration and axon guidance.
Correct answer is: Provides a scaffold for axon extension and binds growth factors
Q.34 Which of the following is a key function of proteoglycans in cartilage?
Store calcium ions
Provide tensile strength
Regulate water retention and compressive stiffness
Crosslink elastin fibers
Explanation - Proteoglycans attract water, giving cartilage its ability to resist compression.
Correct answer is: Regulate water retention and compressive stiffness
Q.35 Which protein is a major component of the interstitial matrix of most connective tissues?
Collagen Type I
Collagen Type IV
Elastin
Laminin
Explanation - Collagen Type I is abundant in interstitial spaces, providing structural integrity.
Correct answer is: Collagen Type I
Q.36 What is the primary role of MMP-9 in the extracellular matrix?
Crosslink collagen fibers
Degrade gelatin and type IV collagen during tissue remodeling
Store growth factors
Signal to neurons
Explanation - MMP-9 breaks down ECM components, allowing cell migration during healing.
Correct answer is: Degrade gelatin and type IV collagen during tissue remodeling
Q.37 Which component of the extracellular matrix is most abundant in the basement membrane?
Elastin
Collagen Type IV
Collagen Type I
Fibronectin
Explanation - Collagen Type IV forms a network that is the major structural protein of basement membranes.
Correct answer is: Collagen Type IV
Q.38 Which enzyme is inhibited by tissue inhibitors of metalloproteinases (TIMPs)?
Lysyl oxidase
Matrix metalloproteinases
DNA polymerase
RNA polymerase
Explanation - TIMPs regulate MMP activity to control ECM degradation.
Correct answer is: Matrix metalloproteinases
Q.39 Which extracellular matrix protein is primarily responsible for the elasticity of lungs?
Collagen Type I
Collagen Type IV
Elastin
Laminin
Explanation - Elastin fibers in lung tissue enable stretch and recoil during breathing.
Correct answer is: Elastin
Q.40 What is the primary function of hyaluronic acid in the extracellular matrix?
Serve as a scaffold for cell adhesion
Provide tensile strength
Regulate water retention and tissue hydration
Crosslink collagen fibers
Explanation - Hyaluronic acid attracts water, maintaining tissue hydration and pliability.
Correct answer is: Regulate water retention and tissue hydration
Q.41 Which of the following is NOT a type of proteoglycan?
Decorin
Perlecan
Collagen
Versican
Explanation - Collagen is a fibrous protein; proteoglycans have a core protein with GAG chains.
Correct answer is: Collagen
Q.42 How do fibroblasts respond to increased mechanical tension in the extracellular matrix?
Decrease collagen production
Increase collagen and elastin production
Stop migrating
Switch to a neuronal phenotype
Explanation - Mechanical tension stimulates fibroblasts to synthesize more ECM to reinforce the tissue.
Correct answer is: Increase collagen and elastin production
Q.43 Which of the following statements about integrins is true?
They are secreted growth factors
They form covalent bonds with collagen
They transduce mechanical signals between the ECM and the cytoskeleton
They are enzymes that degrade proteoglycans
Explanation - Integrins link the ECM to the actin cytoskeleton and transmit signals.
Correct answer is: They transduce mechanical signals between the ECM and the cytoskeleton
Q.44 Which type of collagen is primarily found in the skin’s dermis?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen Type I provides tensile strength to the dermis.
Correct answer is: Collagen Type I
Q.45 What is the main function of the glycoprotein fibronectin in tissue repair?
Serve as an electrical conductor
Promote cell adhesion and migration
Bind to DNA
Regulate ion transport
Explanation - Fibronectin forms a scaffold that supports cell movement during healing.
Correct answer is: Promote cell adhesion and migration
Q.46 Which component of the extracellular matrix contributes most to its viscoelastic properties?
Collagen Type I
Proteoglycans
Elastin
Fibronectin
Explanation - Proteoglycans provide water retention and resistance to compression, giving viscoelasticity.
Correct answer is: Proteoglycans
Q.47 Which enzyme is responsible for the initial cleavage of pro-collagen chains during collagen maturation?
Matrix metalloproteinase
Procollagen C-endopeptidase
Procollagen N-endopeptidase
Lysyl oxidase
Explanation - Procollagen N-endopeptidase removes N-terminal propeptides, enabling fibril assembly.
Correct answer is: Procollagen N-endopeptidase
Q.48 Which extracellular matrix component directly binds to and presents growth factors such as TGF-β to cells?
Collagen Type I
Fibronectin
Proteoglycans
Elastin
Explanation - The GAG chains of proteoglycans can sequester and regulate release of growth factors.
Correct answer is: Proteoglycans
Q.49 What is the main role of elastin in arterial walls?
Provide structural support for blood clotting
Allow arteries to stretch and recoil during blood flow
Store calcium for bone mineralization
Serve as a scaffold for fibroblasts
Explanation - Elastin fibers give arteries elasticity, accommodating pulsatile blood pressure.
Correct answer is: Allow arteries to stretch and recoil during blood flow
Q.50 Which of the following molecules is a glycosaminoglycan (GAG) found in the ECM?
Hyaluronic acid
Elastin
Collagen
Fibronectin
Explanation - Hyaluronic acid is a long unbranched GAG that is part of proteoglycans.
Correct answer is: Hyaluronic acid
Q.51 What is the primary role of matrix metalloproteinase (MMP) activity during tissue remodeling?
Synthesize new ECM proteins
Crosslink collagen fibers
Degrade existing ECM components to allow cell migration
Store ions in the matrix
Explanation - MMPs remodel the ECM by breaking down structural proteins, facilitating cell movement.
Correct answer is: Degrade existing ECM components to allow cell migration
Q.52 Which type of collagen is primarily found in cartilage and provides compressive strength?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen II forms dense networks in cartilage that resist compression.
Correct answer is: Collagen Type II
Q.53 What is the main function of proteoglycans in the interstitial matrix?
Serve as electrical conductors
Store calcium for bone formation
Bind water and maintain tissue hydration
Crosslink elastin fibers
Explanation - Proteoglycans attract water, contributing to tissue compliance and cushioning.
Correct answer is: Bind water and maintain tissue hydration
Q.54 Which enzyme crosslinks lysine residues in collagen to stabilize fibrils?
Collagenase
Lysyl oxidase
MMP-2
TIMP
Explanation - Lysyl oxidase oxidatively deaminates lysine, forming crosslinks between collagen strands.
Correct answer is: Lysyl oxidase
Q.55 What is the role of fibronectin in wound healing?
Inhibit cell migration
Provide a scaffold for cell attachment and migration
Crosslink collagen fibers
Store ions in the ECM
Explanation - Fibronectin deposition facilitates cell migration into the wound area.
Correct answer is: Provide a scaffold for cell attachment and migration
Q.56 Which component of the ECM directly binds to cell-surface integrins to mediate cell adhesion?
Collagen Type I
Collagen Type IV
Fibronectin
Laminin
Explanation - Fibronectin contains RGD motifs that are recognized by integrins for adhesion.
Correct answer is: Fibronectin
Q.57 What does the 'RGD' motif in fibronectin stand for?
Arginine-Glycine-Aspartate
Ribose-Glycine-Delta
Residue-Glycine-Dimer
RNA-Glycoprotein-Disulfide
Explanation - RGD is a tripeptide sequence that integrins recognize for cell binding.
Correct answer is: Arginine-Glycine-Aspartate
Q.58 Which ECM component is most abundant in bone?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen I forms the organic scaffold that is mineralized in bone tissue.
Correct answer is: Collagen Type I
Q.59 Which of the following is a primary function of the extracellular matrix during tissue regeneration?
Produce electrical signals
Provide structural support and sequester growth factors
Generate heat
Produce neurotransmitters
Explanation - ECM supports new tissue growth and binds signaling molecules to direct cell behavior.
Correct answer is: Provide structural support and sequester growth factors
Q.60 What is the role of matrix metalloproteinases (MMPs) in the remodeling of the extracellular matrix?
Crosslink collagen fibers
Synthesize new collagen
Degrade extracellular matrix proteins
Bind growth factors
Explanation - MMPs enzymatically break down ECM components to allow cell migration and tissue remodeling.
Correct answer is: Degrade extracellular matrix proteins
Q.61 Which of the following best describes the function of hyaluronic acid in the extracellular matrix?
Provides tensile strength
Acts as a scaffold for cell adhesion
Regulates water retention and provides compressive resistance
Crosslinks collagen fibers
Explanation - Hyaluronic acid attracts water, keeping tissues hydrated and soft.
Correct answer is: Regulates water retention and provides compressive resistance
Q.62 Which of the following is NOT an extracellular matrix protein?
Collagen
Fibronectin
Hemoglobin
Elastin
Explanation - Hemoglobin is an intracellular protein found in red blood cells, not part of the ECM.
Correct answer is: Hemoglobin
Q.63 Which enzyme is responsible for the crosslinking of elastin fibers in the extracellular matrix?
Collagenase
Lysyl oxidase
Elastase
Matrix metalloproteinase
Explanation - Lysyl oxidase catalyzes oxidative deamination of lysine residues, enabling crosslink formation.
Correct answer is: Lysyl oxidase
Q.64 What is the main function of proteoglycans in cartilage?
Provide tensile strength
Store calcium ions
Retain water and provide compressive resistance
Crosslink elastin fibers
Explanation - Proteoglycans in cartilage attract water, helping tissues resist compression during movement.
Correct answer is: Retain water and provide compressive resistance
Q.65 Which protein is a key component of the basement membrane that interacts with integrins to influence cell behavior?
Collagen Type I
Collagen Type IV
Elastin
Fibronectin
Explanation - Collagen Type IV forms a network in the basement membrane and engages integrins to signal cells.
Correct answer is: Collagen Type IV
Q.66 Which of the following molecules is NOT involved in the structural integrity of the extracellular matrix?
Collagen
Fibronectin
DNA
Laminin
Explanation - DNA is a genetic material inside cells, not a structural ECM component.
Correct answer is: DNA
Q.67 What is the function of integrin receptors in cells?
They degrade extracellular matrix proteins
They transmit signals between the extracellular matrix and the cell interior
They synthesize collagen
They produce ATP
Explanation - Integrins are transmembrane receptors that sense ECM and relay signals inside the cell.
Correct answer is: They transmit signals between the extracellular matrix and the cell interior
Q.68 Which extracellular matrix component is most abundant in connective tissue and provides tensile strength?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen I is the main structural protein that resists pulling forces in connective tissues.
Correct answer is: Collagen Type I
Q.69 Which of the following is an enzymatic process that leads to the removal of propeptide sequences from procollagen?
MMP activation
Collagen crosslinking
Procollagen N-endopeptidase activity
Lysyl oxidase activity
Explanation - Procollagen N-endopeptidases cleave N-terminal propeptides, allowing collagen fibril formation.
Correct answer is: Procollagen N-endopeptidase activity
Q.70 What is the role of elastin in the extracellular matrix?
Provide tensile strength
Serve as a scaffold for cell attachment
Enable tissue elasticity and recoil after stretching
Store calcium ions
Explanation - Elastin fibers allow tissues like arteries and lungs to stretch and return to shape.
Correct answer is: Enable tissue elasticity and recoil after stretching
Q.71 Which of the following is a major function of hyaluronic acid in the extracellular matrix?
Crosslink collagen fibers
Bind calcium ions
Provide tensile strength
Retain water and provide compressive resistance
Explanation - Hyaluronic acid attracts water, keeping tissues hydrated and cushioning against compression.
Correct answer is: Retain water and provide compressive resistance
Q.72 Which protein is a key component of the basement membrane and interacts with cell-surface receptors to influence cell migration and differentiation?
Collagen Type I
Laminin
Elastin
Fibronectin
Explanation - Laminin provides a scaffold in basement membranes and signals via integrins to control cell behavior.
Correct answer is: Laminin
Q.73 Which enzyme is primarily responsible for degrading gelatin and type IV collagen during tissue remodeling?
MMP-2
MMP-9
Collagenase
Elastase
Explanation - MMP-9 efficiently digests gelatin and type IV collagen, facilitating cell migration.
Correct answer is: MMP-9
Q.74 Which of the following ECM components provides a scaffold that supports cell adhesion and migration during wound healing?
Collagen Type I
Laminin
Fibronectin
Proteoglycans
Explanation - Fibronectin fibers are deposited at the wound site to guide cell movement.
Correct answer is: Fibronectin
Q.75 What is the main function of matrix metalloproteinases (MMPs) in the extracellular matrix?
Crosslink collagen fibers
Degrade ECM components to allow cell migration and remodeling
Synthesize new collagen
Bind growth factors
Explanation - MMPs break down ECM proteins, creating pathways for migrating cells during healing.
Correct answer is: Degrade ECM components to allow cell migration and remodeling
Q.76 Which extracellular matrix protein is most abundant in cartilage and is responsible for providing compressive strength?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen II forms dense fibrils in cartilage, giving it the ability to resist compression.
Correct answer is: Collagen Type II
Q.77 What is the primary function of proteoglycans in the extracellular matrix?
Provide electrical conductivity
Store calcium for bone mineralization
Retain water and provide compressive resistance
Crosslink elastin fibers
Explanation - Proteoglycans attract water, keeping tissues hydrated and cushioning them against compression.
Correct answer is: Retain water and provide compressive resistance
Q.78 Which of the following best describes the interaction between integrins and extracellular matrix proteins?
Integrins degrade ECM proteins
Integrins provide structural support to ECM
Integrins bind ECM proteins to transmit mechanical and chemical signals to cells
Integrins are secreted proteins that bind growth factors
Explanation - Integrins serve as receptors that connect the ECM to the cell’s cytoskeleton and signaling pathways.
Correct answer is: Integrins bind ECM proteins to transmit mechanical and chemical signals to cells
Q.79 Which ECM component is a key structural protein in bone, providing the framework for mineral deposition?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen I is the most abundant protein in bone and serves as the scaffold for hydroxyapatite mineralization.
Correct answer is: Collagen Type I
Q.80 Which enzyme is involved in the crosslinking of collagen fibers in the extracellular matrix?
Collagenase
Lysyl oxidase
MMP-2
TIMP
Explanation - Lysyl oxidase catalyzes covalent crosslink formation between lysine residues in collagen and elastin.
Correct answer is: Lysyl oxidase
Q.81 Which extracellular matrix protein directly binds to growth factors and helps regulate their availability to cells?
Collagen Type I
Fibronectin
Proteoglycans
Elastin
Explanation - The negatively charged GAG chains of proteoglycans bind growth factors, modulating their local concentration.
Correct answer is: Proteoglycans
Q.82 What is the main function of fibronectin during tissue repair?
Inhibit cell adhesion
Provide a scaffold for cell migration and adhesion
Crosslink elastin fibers
Store calcium ions
Explanation - Fibronectin deposition facilitates cell movement and wound closure.
Correct answer is: Provide a scaffold for cell migration and adhesion
Q.83 Which of the following is NOT a function of the extracellular matrix?
Provide mechanical support to tissues
Serve as a reservoir for growth factors
Generate electrical signals in the body
Facilitate cell signaling and adhesion
Explanation - The ECM does not directly generate electrical signals; that function is performed by cells.
Correct answer is: Generate electrical signals in the body
Q.84 What is the main role of MMPs in tissue remodeling?
Crosslink collagen fibers
Degrade extracellular matrix components
Store calcium ions
Serve as cell adhesion molecules
Explanation - MMPs enzymatically break down ECM proteins to allow cell migration and tissue remodeling.
Correct answer is: Degrade extracellular matrix components
Q.85 Which extracellular matrix protein is a major component of the basement membrane and interacts with integrins?
Collagen Type I
Laminin
Elastin
Fibronectin
Explanation - Laminin forms a scaffold in basement membranes and binds integrins to influence cell behavior.
Correct answer is: Laminin
Q.86 What is the primary role of elastin in the extracellular matrix?
Provide tensile strength
Serve as a scaffold for cell adhesion
Enable tissue elasticity and recoil after stretching
Store calcium ions
Explanation - Elastin fibers give tissues like arteries and lungs elasticity, allowing them to stretch and return to shape.
Correct answer is: Enable tissue elasticity and recoil after stretching
Q.87 Which component of the extracellular matrix is essential for binding growth factors and modulating their release?
Collagen Type I
Fibronectin
Proteoglycans
Elastin
Explanation - Proteoglycans’ glycosaminoglycan chains bind growth factors, regulating their bioavailability.
Correct answer is: Proteoglycans
Q.88 Which of the following is an enzyme that crosslinks lysine residues in collagen to stabilize fibrils?
Collagenase
Lysyl oxidase
MMP-2
TIMP
Explanation - Lysyl oxidase oxidatively deaminates lysine residues, forming covalent crosslinks in collagen.
Correct answer is: Lysyl oxidase
Q.89 What is the role of matrix metalloproteinases in the extracellular matrix during wound healing?
Crosslink collagen fibers
Degrade ECM components to allow cell migration
Synthesize new collagen
Store calcium ions
Explanation - MMPs remodel the ECM by breaking down proteins, enabling cells to move into the wound site.
Correct answer is: Degrade ECM components to allow cell migration
Q.90 Which extracellular matrix protein is a major structural component of cartilage?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen II is the main fibrillar protein in cartilage, providing compressive strength.
Correct answer is: Collagen Type II
Q.91 Which of the following proteins is NOT a major component of the extracellular matrix?
Collagen
Fibronectin
Hemoglobin
Elastin
Explanation - Hemoglobin is a cytoplasmic protein of red blood cells, not an extracellular matrix component.
Correct answer is: Hemoglobin
Q.92 Which of the following ECM proteins directly interacts with integrin receptors to mediate cell adhesion?
Collagen Type I
Collagen Type IV
Fibronectin
Laminin
Explanation - Fibronectin contains RGD motifs recognized by integrins, facilitating cell attachment.
Correct answer is: Fibronectin
Q.93 Which of the following is a glycosaminoglycan (GAG) that is commonly found in cartilage?
Hyaluronic acid
Elastin
Collagen
Fibronectin
Explanation - Hyaluronic acid is a GAG present in cartilage that retains water and contributes to compressive resilience.
Correct answer is: Hyaluronic acid
Q.94 What is the main function of proteoglycans in the extracellular matrix?
Provide tensile strength
Bind calcium ions
Retain water and provide compressive resistance
Crosslink elastin fibers
Explanation - Proteoglycans attract water and resist compression, especially in cartilage.
Correct answer is: Retain water and provide compressive resistance
Q.95 Which extracellular matrix protein is a key component of the basement membrane?
Collagen Type I
Collagen Type IV
Elastin
Fibronectin
Explanation - Collagen IV forms a network in basement membranes, providing structural support.
Correct answer is: Collagen Type IV
Q.96 Which enzyme is primarily responsible for the degradation of type IV collagen in basement membranes?
MMP-2
MMP-9
Collagenase
Elastase
Explanation - MMP-9 efficiently cleaves type IV collagen, allowing cells to remodel basement membranes.
Correct answer is: MMP-9
Q.97 Which ECM component provides mechanical support and elasticity in blood vessels?
Collagen Type I
Collagen Type II
Elastin
Fibronectin
Explanation - Elastin fibers allow arteries and veins to stretch and recoil as blood flows.
Correct answer is: Elastin
Q.98 What is the primary function of the extracellular matrix in bone tissue?
Provide structural support and store minerals
Generate electrical signals
Store glucose
Transport oxygen
Explanation - Bone ECM contains collagen and mineral crystals, giving bone its strength and rigidity.
Correct answer is: Provide structural support and store minerals
Q.99 Which of the following is a key regulator of matrix metalloproteinase activity in the extracellular matrix?
Tissue inhibitors of metalloproteinases (TIMPs)
Collagen
Elastin
Fibronectin
Explanation - TIMPs bind and inhibit MMPs, maintaining balanced ECM remodeling.
Correct answer is: Tissue inhibitors of metalloproteinases (TIMPs)
Q.100 Which extracellular matrix component is most abundant in the skin’s dermis?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen I forms thick fibers in the dermis, providing tensile strength.
Correct answer is: Collagen Type I
Q.101 What is the function of hyaluronic acid in the extracellular matrix?
Provide tensile strength
Serve as a scaffold for cell adhesion
Regulate water retention and provide compressive resistance
Crosslink collagen fibers
Explanation - Hyaluronic acid attracts water, keeping tissues hydrated and cushioning them against compression.
Correct answer is: Regulate water retention and provide compressive resistance
Q.102 Which extracellular matrix protein is a major structural component of cartilage?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen II is the main fibrillar protein in cartilage, providing compressive strength.
Correct answer is: Collagen Type II
Q.103 Which of the following is NOT a function of the extracellular matrix?
Provide mechanical support
Serve as a reservoir for growth factors
Generate electrical signals in the body
Facilitate cell signaling and adhesion
Explanation - ECM does not directly produce electrical signals; that role is performed by cells and tissues.
Correct answer is: Generate electrical signals in the body
Q.104 What is the primary role of matrix metalloproteinases (MMPs) in tissue remodeling?
Crosslink collagen fibers
Degrade extracellular matrix components
Store calcium ions
Serve as cell adhesion molecules
Explanation - MMPs enzymatically break down ECM proteins to allow cell migration and tissue remodeling.
Correct answer is: Degrade extracellular matrix components
Q.105 Which extracellular matrix component directly interacts with integrin receptors to mediate cell adhesion?
Collagen Type I
Collagen Type IV
Fibronectin
Laminin
Explanation - Fibronectin contains RGD motifs recognized by integrins, allowing cells to adhere.
Correct answer is: Fibronectin
Q.106 Which of the following is a key component of the basement membrane?
Collagen Type I
Collagen Type IV
Elastin
Fibronectin
Explanation - Collagen IV forms a meshwork in basement membranes, providing structural support.
Correct answer is: Collagen Type IV
Q.107 What is the main function of elastin in the extracellular matrix?
Provide tensile strength
Serve as a scaffold for cell adhesion
Enable tissue elasticity and recoil after stretching
Store calcium ions
Explanation - Elastin fibers allow tissues such as arteries and lungs to stretch and return to their original shape.
Correct answer is: Enable tissue elasticity and recoil after stretching
Q.108 Which of the following ECM proteins is a major structural component of bone, providing the framework for mineral deposition?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen I is the primary organic matrix of bone, onto which minerals are deposited.
Correct answer is: Collagen Type I
Q.109 What is the function of matrix metalloproteinases (MMPs) in the extracellular matrix during wound healing?
Crosslink collagen fibers
Degrade ECM components to allow cell migration
Synthesize new collagen
Store calcium ions
Explanation - MMPs remodel the ECM by breaking down proteins, allowing cells to migrate into the wound site.
Correct answer is: Degrade ECM components to allow cell migration
Q.110 Which of the following is NOT a major function of the extracellular matrix?
Provide mechanical support to tissues
Serve as a reservoir for growth factors
Generate electrical signals in the body
Facilitate cell signaling and adhesion
Explanation - The ECM does not directly generate electrical signals; that function is performed by cells.
Correct answer is: Generate electrical signals in the body
Q.111 Which ECM component is a key structural protein in cartilage?
Collagen Type I
Collagen Type II
Collagen Type III
Collagen Type IV
Explanation - Collagen II is the main fibrillar protein in cartilage, providing compressive strength.
Correct answer is: Collagen Type II
Q.112 Which of the following is NOT a function of the extracellular matrix?
Provide mechanical support
Serve as a reservoir for growth factors
Generate electrical signals in the body
Facilitate cell signaling and adhesion
Explanation - The ECM does not directly generate electrical signals; that function is performed by cells.
Correct answer is: Generate electrical signals in the body
Q.113 Which of the following ECM components provides a scaffold that supports cell adhesion and migration during wound healing?
Collagen Type I
Laminin
Fibronectin
Proteoglycans
Explanation - Fibronectin fibers are deposited at the wound site to guide cell movement.
Correct answer is: Fibronectin