Question 1

You genetically engineer nonadhesive cells to express one variety of cadherins and then mix the cells in various combinations.You then monitor their interactions.What do you observe?
A)The genetically engineered cells adhered preferentially to cells expressing one of the other cadherins.
B)The genetically engineered cells adhered preferentially to cells expressing the same cadherins.
C)The genetically engineered cells did not stick to any other cells.
D)The genetically engineered cells died.
E)The genetically engineered cells migrated to a different location.

Accepted Answer

The genetically engineered cells expressing one variety of cadherins will adhered preferentially to cells expressing the same cadherins. This is because cadherins are transmembrane proteins that mediate cell-cell adhesion by binding to other cadherins of the same type on adjacent cells. Therefore, cells expressing the same type of cadherin will have a stronger adhesion than cells expressing different types of cadherin.

Question 2

The bonds that selectins form with their ligands become _______ when the interaction is __________.
A)stronger,placed under mechanical stress
B)weaker,placed under mechanical stress
C)stronger,exposed to a higher temperature
D)more elastic,exposed to a higher temperature
E)more elastic,placed under mechanical stress

Accepted Answer

Selectins form bonds with their ligands that become stronger when placed under mechanical stress, a phenomenon known as catch bonds, which enhances cell adhesion under flow conditions.

Question 3

From the apical surface to the basal surface of an epithelial cell,what is the order of cell junctions observed in the junctional complex?
A)tight junction,belt desmosome,spot desmosomes,gap junctions
B)tight junction,gap junction,belt desmosome,spot desmosomes
C)belt desmosome,tight junction,gap junctions,spot desmosomes
D)belt desmosome,gap junctions,tight junctions,spot desmosomes
E)gap junctions,spot desmosomes,belt desmosome,tight junction

Accepted Answer

The answer of From the apical surface to the basal...

Question 4

What can be described as a tightly adherent,polarized cell layer?
A)a mesenchyme
B)cartilage
C)an epithelium
D)a mesothelium
E)mesoderm

Accepted Answer

An epithelium is a tightly adherent, polarized cell layer that covers and lines surfaces throughout the body. Mesenchyme refers to embryonic connective tissue, cartilage refers to a specialized type of connective tissue, a mesothelium is a type of epithelium that lines body cavities, and mesoderm refers to one of the primary germ layers in embryos.

Question 5

The binding of lymphocytes to the endothelial lining of venules in peripheral lymph node frozen tissue sections could be blocked in what way? This demonstrated the existence of what kind of molecule?
A)Treatment with antibodies against specific lymphocyte surface glycoproteins,selectins
B)Treatment with antibodies against specific lymphocyte surface glycoproteins,IgSFs
C)Treatment with antibodies against specific lymphocyte surface glycoproteins,integrins
D)Treatment with antibodies against specific ECM glycoproteins,selectins
E)Treatment with antibodies against specific ECM glycoproteins,cadherins

Accepted Answer

The answer of The binding of lymphocytes to the endothelial...

Question 6

What determines the strength of adhesion between apposing cells held together by cadherins?
A)the length of the cadherins connecting the cells
B)the width of the cadherins connecting the cells
C)the amount of tryptophan in the cadherins connecting the cells
D)the number of cadherins in a cluster connecting the cells
E)the number of tyrosine residues in the cadherins connecting the cells

Accepted Answer

The number of cadherins in a cluster connecting the cells determines the strength of adhesion between apposing cells held together by cadherins. The more cadherins present in a cluster connecting the cells, the stronger the adhesion between the cells. This is because more cadherins result in a larger surface area for interactions between the cells, leading to stronger binding. The other choices listed (A, B, C, and E) are not factors that determine the strength of adhesion between apposing cells held together by cadherins.

Question 7

What is thought to be the origin of immunoglobulins?
A)They may be derived from immune system molecules in invertebrates.
B)They may be derived from cell-adhesion receptors in invertebrates.
C)They may be derived from cell-adhesion receptors in fish.
D)They may be derived from cell-adhesion molecules in amphibians.
E)They may be derived from immune system molecules in reptiles.

Accepted Answer

The answer of What is thought to be the origin...

Question 8

________ are members of an integral membrane glycoprotein family that bind to specific sugar arrangements in oligosaccharides that project from the surfaces of other cells.
A)Selectins
B)Integrins
C)Immunoglobulin super family proteins
D)Cadherins
E)Calmodulins

Accepted Answer

Selectins are known to bind to specific sugar arrangements in oligosaccharides that are present on the surfaces of other cells, making them members of an integral membrane glycoprotein family. Integrins, cadherins, and immunoglobulin superfamily proteins are involved in other types of cell-cell interactions. Calmodulins are not glycoproteins and do not interact with oligosaccharides.

Question 9

What can be described as solitary,nonadhesive,nonpolarized migratory cells?
A)a mesenchyme
B)cartilage
C)an epithelium
D)a mesothelium
E)an endothelium

Accepted Answer

Mesenchyme cells are solitary, nonadhesive, and nonpolarized migratory cells that are derived from embryonic mesoderm. They give rise to various tissues and organs, such as connective tissues, bones, cartilage, and muscles. Cartilage consists of chondrocytes embedded in an extracellular matrix, which is not migratory, nonadhesive, and polarized. Epithelial cells, mesothelial cells, and endothelial cells are all polarized, nonmigratory, and adhesive cells that form linings and barriers in different tissues and organs.

Question 10

You disaggregate cells from two different developing organs and mix them together.Initially,they form a mixed clump.What happens next?
A)The clump stabilizes.
B)The cells sort themselves out so that each cell adhered only to cells of the same type.
C)The mixed clump persists.
D)The clumped cells die.
E)The clump forms a mesenchyme.

Accepted Answer

This phenomenon is known as cell sorting, where cells segregate based on their tissue type and adhere to cells of the same type. Cell sorting is an important process during organ development and helps in the proper arrangement of cells in different tissues.

Question 11

The loss of cadherin function may be instrumental in what disease state?
A)colds
B)the spread of benign tumors
C)the spread of malignant tumors
D)influenza
E)AIDS

Accepted Answer

The loss of cadherin function has been shown to play a role in the spread of malignant tumors, as it disrupts the normal adhesion between cells and allows for uncontrolled cell migration and invasion.

Question 12

Calcium ions form bridges between ________.
A)successive domains of a given cadherin molecule
B)cadherins on adjacent cells
C)cadherins on the same cell
D)cadherins and IgSFs
E)IgSFs and selectins

Accepted Answer

The answer of Calcium ions form bridges between ________.
A)successive domains...

Question 13

Which of the following tissues are typically derived from mesenchymal cells?
A)mesodermal tissues
B)ectodermal tissues
C)only blood
D)only muscle
E)mesodermal tissues,blood and muscle

Accepted Answer

The answer of Which of the following tissues are typically...

Question 14

Cadherins appear to be important in holding cells together in __________ tissues.
A)mesenchymal
B)loosely cohesive
C)tightly cohesive
D)noncohesive
E)gel-like

Accepted Answer

Cadherins are transmembrane proteins that play a crucial role in cell-cell adhesion in epithelial tissues. They are responsible for binding cells tightly together to form a stable tissue structure. Cadherins are also important in the development of the nervous system, where they mediate the process of axon guidance.

Question 15

What is the function of most IgSFs?
A)cell adhesion
B)cell division
C)mediating specific interactions of epithelial cells with cells needed for immune response
D)mediating specific interactions of lymphocytes with cells needed for the immune response
E)cell fusion

Accepted Answer

The function of most IgSFs is to mediate specific interactions of lymphocytes with cells needed for the immune response.

Question 16

While most IgSF members are involved in various aspects of immune function,some of them mediate ________ cell-cell adhesion.
A)calcium-dependent
B)calcium-independent
C)magnesium-dependent
D)manganese-dependent
E)iron-independent

Accepted Answer

IgSF members that mediate cell-cell adhesion are involved in a calcium-independent manner. Calcium-independent IgSF members include NCAM, L1, and CHL1.

Question 17

When tight junctions,gap junctions and desmosomes are arranged in a specific array,the assortment of surface specializations is called a(n)__________.
A)junctional array
B)synaptonemal complex
C)belt complex
D)junctional complex
E)spot complex

Accepted Answer

The specific arrangement of tight junctions, gap junctions, and desmosomes is called a junctional complex.

Question 18

Lymphocytes are isolated and labeled with radioactive isotopes.They are then exposed to frozen tissue sections of a lymphoid organ.What happens?
A)The lymphocytes bind uniformly to the sections.
B)The lymphocytes bind to each other.
C)The lymphocytes selectively adhere to the endothelial lining of venules in peripheral lymph nodes.
D)The lymphocytes selectively adhere to the endothelial lining of arterioles in peripheral lymph nodes.
E)The lymphocytes do not stick to the sections.

Accepted Answer

Lymphocytes selectively adhere to the endothelial lining of venules in peripheral lymph nodes, allowing them to enter the lymphoid organ and participate in immune responses. This is known as the homing process. The radioactive isotopes help in identifying the binding of lymphocytes to the venules. Option A is unlikely as lymphocytes do not bind uniformly to sections. Option B is incorrect as lymphocytes do not bind to each other in the absence of any stimulus. Option D is incorrect as lymphocytes do not selectively adhere to the endothelial lining of arterioles. Option E is unlikely as lymphocytes are expected to adhere to the lymphoid tissue.

Question 19

What type of cell adhesion molecule is associated with cells being held together by adherens junctions at the site of the junction?
A)adherins
B)selectins
C)IgSFs
D)integrins
E)cadherins

Accepted Answer

Cadherins are the cell adhesion molecules that are associated with cells being held together by adherens junctions at the site of the junction. Adherins (A), selectins (B), IgSFs (C), and integrins (D) are not specifically associated with adherens junctions.

Question 20

L1 is an IgSF molecule that has been shown to be important in neural development;it is thought that it may be involved in axon growth within the embryonic nervous system.What evidence supports this statement?
A)L1 mutants always die.
B)L1 mutants show deficits in their vision.
C)People who die of L1-deficiency are often missing two large nerve tracts.
D)People who die of L1-deficiency are often missing a significant portion of their brain.
E)People who die of L1-deficiency are often missing a significant portion of their spinal cord.

Accepted Answer

The fact that people who die of L1-deficiency are often missing two large nerve tracts supports the idea that L1 is involved in axon growth within the embryonic nervous system.

Quiz 7: Interactions Between Cells and Their Environment

You genetically engineer nonadhesive cells to express one variety of cadherins and then mix the cells in various combinations.You then monitor their interactions.What do you observe?

The bonds that selectins form with their ligands become _ when the interaction is ____.

From the apical surface to the basal surface of an epithelial cell,what is the order of cell junctions observed in the junctional complex?

What can be described as a tightly adherent,polarized cell layer?

The binding of lymphocytes to the endothelial lining of venules in peripheral lymph node frozen tissue sections could be blocked in what way? This demonstrated the existence of what kind of molecule?

What determines the strength of adhesion between apposing cells held together by cadherins?

What is thought to be the origin of immunoglobulins?

________ are members of an integral membrane glycoprotein family that bind to specific sugar arrangements in oligosaccharides that project from the surfaces of other cells.

What can be described as solitary,nonadhesive,nonpolarized migratory cells?

You disaggregate cells from two different developing organs and mix them together.Initially,they form a mixed clump.What happens next?

The loss of cadherin function may be instrumental in what disease state?

Calcium ions form bridges between ________.

Which of the following tissues are typically derived from mesenchymal cells?

Cadherins appear to be important in holding cells together in __________ tissues.

What is the function of most IgSFs?

While most IgSF members are involved in various aspects of immune function,some of them mediate ________ cell-cell adhesion.

When tight junctions,gap junctions and desmosomes are arranged in a specific array,the assortment of surface specializations is called a(n) __________.

Lymphocytes are isolated and labeled with radioactive isotopes.They are then exposed to frozen tissue sections of a lymphoid organ.What happens?

What type of cell adhesion molecule is associated with cells being held together by adherens junctions at the site of the junction?

L1 is an IgSF molecule that has been shown to be important in neural development;it is thought that it may be involved in axon growth within the embryonic nervous system.What evidence supports this statement?