Question 1

Collagen fibrils are strengthened by covalent cross-links between _________ and ________ residues on adjacent collagen molecules.
A)lysine, hydroxylysine
B)proline, hydroxyproline
C)lysine, hydroxyproline
D)proline, hydroxylysine
E)proline, lysine

Accepted Answer

Collagen fibrils are strengthened by covalent cross-links that form between lysine and hydroxylysine residues on adjacent collagen molecules. This cross-linking is crucial for the structural integrity and tensile strength of collagen fibers.

Question 2

What substance joins proteoglycans together into gigantic complexes called proteoglycan aggregates?
A)hyaluronidase
B)hyaluronic acid
C)proteoglycase
D)fibronectin
E)laminin

Accepted Answer

Hyaluronic acid is a long, unbranched polysaccharide that provides a backbone for the formation of proteoglycan aggregates. The negatively charged glycosaminoglycan side chains of proteoglycans bind to the positively charged hyaluronic acid, creating a large complex.

Question 3

Mutations in Type I collagen genes cause a potentially lethal condition characterized by extremely fragile bones, thin skin and weak tendons. This condition is called _______.
A)osteogenesis imperfecta
B)Ehler-Danlos syndrome
C)Alport syndrome
D)dwarfism and skeletal deformities
E)diabetes

Accepted Answer

This condition is also known as brittle bone disease and is caused by mutations in genes that code for Type I collagen, a protein that provides strength and structure to bones, skin, and tendons. The resulting fragility of bones can lead to frequent fractures, and the condition can range in severity from mild to lethal. Ehler-Danlos syndrome and Alport syndrome are genetic disorders that affect connective tissue and the kidneys, respectively. Dwarfism and skeletal deformities can have various causes, including genetic mutations, but they do not typically involve collagen. Diabetes is a metabolic disorder caused by insulin imbalance and is not related to collagen mutations.

Question 4

What would be the effect on primordial germ cells when an embryo is exposed to laminin-specific neutralizing antibodies?
A)They arrive at the developing gonad more quickly.
B)Their movement to the developing gonad is disrupted.
C)They begin to divide rapidly.
D)They increase greatly in size.
E)Their nuclei disintegrate.

Accepted Answer

Laminin is an extracellular matrix protein that is important for cell migration and adhesion. Primordial germ cells (PGCs) migrate from the hindgut to the developing gonad during early embryonic development, and this migration process is dependent on the interaction between laminin and integrin receptors on the surface of PGCs. Exposure to laminin-specific neutralizing antibodies would disrupt this interaction and prevent PGCs from migrating properly, resulting in a decrease or delay in their arrival at the developing gonad. Therefore, the effect on PGCs would be a disruption of their movement to the developing gonad.

Question 5

Mutations in collagen genes can lead to a variety of distinct but related defects in collagen matrix structure, one of which causes hyperflexible joints and highly extensible skin. These defects are usually referred to as ______.
A)osteogenesis imperfecta
B)Ehler-Danlos syndromes
C)Alport syndromes
D)Cushing's syndrome
E)diabetes

Accepted Answer

Mutations in collagen genes can lead to Ehler-Danlos syndromes, which are a group of inherited disorders that affect the connective tissues, such as skin, ligaments, and tendons. One of the main symptoms of Ehler-Danlos syndromes is hyperflexible joints and highly extensible skin. Osteogenesis imperfecta, Alport syndromes, Cushing's syndrome, and diabetes are not directly related to collagen gene mutations causing hyperflexible joints and highly extensible skin.

Question 6

Three dimensional masses of organ tissues grown in vitro are called ___________.
A)organs
B)organoids
C)organelles
D)organic matrices

Accepted Answer

Organoids are three dimensional masses of organ tissues grown in vitro. Option A, organs, refers to the complete functional unit that comprises different tissues performing specific functions. Option C, organelles, refers to the specialized subunit present within a cell that has specific functions. Option D, organic matrices, refers to the extracellular matrix produced by cells that provide structural support and signal conductance for cellular communication.

Question 7

What integral membrane protein family made of two membrane-spanning chains ($\alpha$ and $\beta$)is involved in attaching cells to their extracellular microenvironment?
A)laminins
B)fibronectins
C)integrins
D)myosins
E)lysins

Accepted Answer

Integrins are a family of integral membrane proteins made up of two membrane-spanning chains (F1F1F1S1F1F1F10 and F1F1F1S1F1F1F10) that mediate cell-cell and cell-extracellular matrix interactions. They are responsible for attaching cells to their extracellular microenvironment. Laminins and fibronectins are extracellular matrix proteins, not integral membrane proteins. Myosins are contractile proteins involved in muscle contraction, and lysins are enzymes that destroy bacterial cell walls.

Question 8

Basement membranes contain type IV collagen, a nonfibrillar collagen organized in a flattened network. The type IV collagen trimer has some interspersed nonhelical segments. What property does this confer upon basement membranes?
A)strength
B)flexibility
C)extensibility
D)transparency
E)opacity

Accepted Answer

The interspersed nonhelical segments in type IV collagen confer flexibility to basement membranes, allowing them to form a supportive yet adaptable structure for the cells they underlie.

Question 9

The basement membrane of the__________ may thicken abnormally in long-term diabetics causing kidney failure.
A)dermis
B)epidermis
C)glomerulus
D)bladder epithelium
E)pericardium

Accepted Answer

The glomerulus is a component of the kidney responsible for filtering blood. In long-term diabetics, the basement membrane of the glomerulus may thicken abnormally, resulting in kidney failure. The dermis is the layer of skin beneath the epidermis, the bladder epithelium lines the inside of the bladder, and the pericardium is the sac surrounding the heart; none of these are directly related to diabetic kidney failure.

Question 10

Type II collagen gene mutations alter the properties of cartilage tissue and are known to cause _______.
A)osteogenesis imperfecta
B)Ehler-Danlos syndromes
C)Alport syndrome
D)dwarfism and skeletal deformities
E)diabetes

Accepted Answer

Type II collagen is a major component of cartilage tissue. Mutations in the type II collagen gene can alter the properties of the cartilage tissue and lead to dwarfism and skeletal deformities. Osteogenesis imperfecta is caused by mutations in the genes responsible for collagen production in bones, while Ehler-Danlos syndromes are caused by mutations in genes that affect the production of collagen in the skin, joints, and blood vessels. Alport syndrome is caused by mutations in the genes responsible for type IV collagen production, which is found in basement membranes. Diabetes is not associated with type II collagen gene mutations.

Question 11

Organoid tissues are derived by growing cells from all of the following EXCEPT:
A)tissue specific stem cells
B)induced pluripotent stem cells
C)embryonic stem cells
D)certain tumor cells

Accepted Answer

Organoid tissues are not derived from certain tumor cells because these cells may have genetic mutations that could affect their behavior and growth, possibly leading to inaccurate or unpredictable results. It is important to use healthy and controlled cells as a basis for organoid tissue growth.

Question 12

What could be defined as an organized network of extracellular materials found beyond the plasma membrane?
A)intracellular matrix
B)extracellular matrix
C)extracellular nexus
D)intercellular material
E)epicellular matrix

Accepted Answer

The extracellular matrix is a network of extracellular materials found beyond the plasma membrane. It is composed of various macromolecules, including collagen, elastin, proteoglycans, and glycoproteins, that provide structural support and biochemical signaling to cells in tissues. The other answer choices are either incorrect or do not accurately describe the extracellular matrix.

Question 13

Which of the following is NOT a role of proteoglycan?
A)attracting large numbers of cations
B)attracting large numbers of anions
C)maintaining a hydrated extracellular matrix
D)growth factor binding

Accepted Answer

Proteoglycans are known to attract large numbers of cations due to the negatively charged sulfated glycosaminoglycan (GAG) chains attached to the protein core. They also play a crucial role in maintaining a hydrated extracellular matrix and binding growth factors. However, they do not attract large numbers of anions.

Question 14

The degradation of the extracellular matrix, along with cell surface proteins, is accomplished mostly by a _____-containing enzyme family called MMPs.
A)coppers
B)iron
C)zinc
D)magnesium
E)manganese

Accepted Answer

The MMPs enzyme family responsible for the degradation of the extracellular matrix contains zinc as a key component. Therefore, zinc-containing enzymes are the best choice among the options given.

Question 15

If antibodies that neutralize fibronectin are incubated with an embryo through which neural crest cells are migrating, what happens?
A)Neural crest cell movements are inhibited.
B)Neural crest cell movements are excited.
C)Neural crest cells die.
D)Neural crest cells divide.
E)Neural crest cells convert into muscle cells.

Accepted Answer

Fibronectin is an extracellular matrix molecule that provides a substrate for migrating neural crest cells. Antibodies that neutralize fibronectin would prevent neural crest cells from adhering to and moving along the substrate, leading to inhibition of neural crest cell movements.

Question 16

Organoid uses currently include all of the following EXCEPT:
A)patient-individualized testing of efficacy of therapeutic drugs
B)mass testing of efficacy of therapeutic drugs
C)generation of organs for researching disease progression
D)generation of organs to replace those found in the human body

Accepted Answer

Organoids are not yet advanced enough to generate fully functional organs to replace those within the human body. However, research is ongoing to develop this technology for future use in organ transplantation. A, B, and C are all current uses of organoids in research and testing.

Question 17

You place mammary gland epithelial cells in culture and then treat them with enzymes that digest the surrounding extracellular matrix. If extracellular matrix materials are then added back to the cells, what happens?
A)The cells continue to decline in secretory and synthetic activities.
B)The cells digest the extracellular materials through endocytosis.
C)The differentiated state of the cells is restored and the cells produce their usual products.
D)The cells die.
E)The cells become stem cells and differentiate into many different types.

Accepted Answer

Adding back extracellular matrix materials can help restore the differentiated state of the cells and bring them back to producing their usual products. This is because the extracellular matrix plays a crucial role in regulating the function and behavior of cells, including controlling their gene expression and signaling pathways. Digesting the extracellular matrix can disrupt these regulatory signals, but adding it back can help restore them.

Question 18

In the corneal stroma, the uniformity of collagen fiber size and the ordered packing of the fibers confers what property on the corneal stroma?
A)strength
B)flexibility
C)extensibility
D)transparency
E)opacity

Accepted Answer

The uniformity of collagen fiber size and the ordered packing of the fibers in the corneal stroma contribute to its transparency, allowing light to pass through and reach the retina.

Question 19

All collagen family members consist of _____ chains arranged in a _______ in at least part of their length.
A)2, double helix
B)3, double helix
C)3, triple helix
D)3, triple lattice
E)2, triple helix

Accepted Answer

Collagen family members consist of three polypeptide chains arranged in a triple helix in at least part of their length.

Question 20

You place mammary gland epithelial cells in culture and then treat them with enzymes that digest the surrounding extracellular matrix. What happens?
A)The secretory and synthetic activities of the cells decrease.
B)The secretory and synthetic activities of the cells increase.
C)The cells die.
D)The cells differentiate.
E)The secretory and synthetic activities of the cells do not change.

Accepted Answer

The extracellular matrix (ECM) provides structural and biochemical support to surrounding cells. When mammary gland epithelial cells are stripped of the ECM by enzymatic digestion, their normal secretory and synthetic activities decrease because the ECM is crucial for providing signals that maintain these functions.

Quiz 7: Interactions Between Cells and Their Environment

Collagen fibrils are strengthened by covalent cross-links between _ and residues on adjacent collagen molecules.

What substance joins proteoglycans together into gigantic complexes called proteoglycan aggregates?

Mutations in Type I collagen genes cause a potentially lethal condition characterized by extremely fragile bones, thin skin and weak tendons. This condition is called _______.

What would be the effect on primordial germ cells when an embryo is exposed to laminin-specific neutralizing antibodies?

Mutations in collagen genes can lead to a variety of distinct but related defects in collagen matrix structure, one of which causes hyperflexible joints and highly extensible skin. These defects are usually referred to as ______.

Three dimensional masses of organ tissues grown in vitro are called ___________.

What integral membrane protein family made of two membrane-spanning chains ( $\alpha$ and $\beta$ ) is involved in attaching cells to their extracellular microenvironment?

Basement membranes contain type IV collagen, a nonfibrillar collagen organized in a flattened network. The type IV collagen trimer has some interspersed nonhelical segments. What property does this confer upon basement membranes?

The basement membrane of the__________ may thicken abnormally in long-term diabetics causing kidney failure.

Type II collagen gene mutations alter the properties of cartilage tissue and are known to cause _______.

Organoid tissues are derived by growing cells from all of the following EXCEPT:

What could be defined as an organized network of extracellular materials found beyond the plasma membrane?

Which of the following is NOT a role of proteoglycan?

The degradation of the extracellular matrix, along with cell surface proteins, is accomplished mostly by a _____-containing enzyme family called MMPs.

If antibodies that neutralize fibronectin are incubated with an embryo through which neural crest cells are migrating, what happens?

Organoid uses currently include all of the following EXCEPT:

You place mammary gland epithelial cells in culture and then treat them with enzymes that digest the surrounding extracellular matrix. If extracellular matrix materials are then added back to the cells, what happens?

In the corneal stroma, the uniformity of collagen fiber size and the ordered packing of the fibers confers what property on the corneal stroma?

All collagen family members consist of _ chains arranged in a ___ in at least part of their length.

You place mammary gland epithelial cells in culture and then treat them with enzymes that digest the surrounding extracellular matrix. What happens?