Ch 10 learning curve

Motor proteins cause movement by: (1) undergoing a conformational change, (2) harnessing energy from ATP, (3) binding to the cytoskeleton.

All are correct

What is the advantage of forcing materials to travel through cells instead of between cells?

Cells can control which materials are transported. Exposure to bacteria or viruses is limited. Exposure to toxins is limited.

A tissue is generally composed of several organs.

FALSE

Keratinocytes are pigment cells contained in the epidermis of skin.

FALSE

What is the best characterization of the minus end of a dynamic filament?

It is slow growing.

Could an isolated melanin granule move along an actin microfilament?

No, motor proteins are specific for the type of filament they bind.

The epidermis contains several layers and receives its nutrients from the dermis by diffusion. Which of the following explains why the outermost layers of the epidermis consist of dead cells?

One of the major functions of the epidermis is forming a waterproof barrier. Once that barrier is formed, nutrients cannot pass through it and the cells beyond that layer die.

The extracellular matrix is composed of: (1) proteins; (2) polysaccharides; (3) nucleic acids.

Statements (1) and (2) are correct.

Many scientists are working to generate organs in vitro. In some cases, cells are seeded onto a "scaffold" shaped like the desired target organ. Such scaffolds are likely composed of extracellular matrix proteins.

TRUE

Predict what would happen if an embryonic epidermal cell switched from expressing E-cadherin to N-cadherin.

The cell would leave the epidermis and join the neural cells.

The area where the epidermis and the dermis meet is highly folded so that the epidermis "fits" into the dermis. What do you think is the function of this highly folded area?

The epidermis is the outer layer and is under constant physical stress. This highly folded area between the epidermis and the dermis gives the epidermis additional support and protection against abrasive stress.

Imagine that you are examining a mouse that does not produce basal lamina in the skin. How will this mouse be different from a normal, wild-type mouse?

The epidermis will not be connected to the dermis.

Gap junctions and plasmodesmata have what feature in common?

They both allow direct transport of materials between cells.

Which of the following is a false statement about the motor proteins myosin and kinesin?

They both move cargo to the plus end of a cytoskeletal filament.

Cadherin is an example of:

a cell adhesion molecule.

An epithelial tissue is defined as:

a collection of cells that lines cavities or outside surfaces.

A researcher is assessing the expression of a certain protein in cells. This protein appears as a "web" in the cytoplasm of cells. The protein is likely:

a component of the cytoskeleton.

The basal lamina is:

a specialized form of the extracellular matrix found beneath all epithelial tissues.

Microvilli are located on the ______ of a cell.

apical surface

Which of the following is a specific type of extracellular matrix?

basal lamina

Cadherins bind to which type of cytoskeletal element(s)?

both intermediate filaments and microfilaments

Which of the following cytoskeletal elements is capable of assembling and disassembling in the cell?

both microtubules and microfilaments

Which one of the following cytoskeletal elements is associated with supporting the movement of materials inside the cell?

both microtubules and microfilaments

The natural loss of dead cells from the surface of your skin is a result of:

both the loss of adherens junctions between epithelial cells, and the breakdown of desmosomes.

The classic experiment using isolated cells from two species of sponges provided evidence that:

cell adhesion molecules are species specific.

If intermediate filaments were capable of dynamic instability, which of the following outcomes would be most likely?

cell adhesion would be affected

Which of the following is a component of the extracellular matrix made by a plant cell?

cellulose

Which of the following are components of the animal extracellular matrix?

collagen and laminin

A researcher is studying a population of cells that are shaped normally, but appear to slide past one another. This is likely the result of mutations in genes encoding:

components of cell junctions.

Which motor protein(s) would you find in a flagellum?

dynein

Which one of the following is not a cellular function of microfilaments?

flagellar movement

Where would you find a cell adhesion molecule?

in a cell junction

In skin, the cells of the epidermis connect to the basal lamina through cellular junctions known as hemidesmosomes. Select the cytoskeletal element that helps maintain the integrity of this connection.

intermediate filaments

Which one of the cytoskeletal elements is associated with providing the cell with mechanical strength?

intermediate filaments

Which of the following could not be a part of the extracellular matrix made by an animal cell?

lignin

Myosin is a motor protein that associates with:

microfilaments

Dynamic instability is the rapid assembly and disassembly of:

microtubules

Dynein is a motor protein found attached to:

microtubules

Kinesin is a motor protein found attached to:

microtubules

Macrophage cells undergo a process called phagocytosis in which material is brought into a cell in the form of membrane vesicles and then transported along microtubules toward the cell center. Assuming that the centrosome is near the cell center, you can predict that these vesicles are moving to the _____ end of microtubules using the motor protein _____.

minus end; dynein

Which one of the following is not a cellular function associated with microtubules?

muscle contraction

The internal cytoskeletal structure of cilia and flagella grows out from a structure called a basal body located near the cell surface. Based on this information, where would you predict the plus end of the microtubules to be located?

near the tip of the cilia or flagella

Which of the following structures would be located in the dermis of the skin?

nerve endings connective tissue sweat glands blood vessels

Which type of cellular junction(s) allow(s) for the movement of proteins and transfer RNA molecules?

plasmodesmata

In nerve cells, the centrosome is located near the nucleus. Vesicles move from near the nucleus to the end of long extensions (axons) along microtubules. Based on these two facts, it is possible to conclude that these vesicles are moving in the _____ direction on the microtubule using the motor protein _____.

plus end; kinesin

A cadherin protein can only bind to:

the extracellular domain of the same type of cadherin.

The most likely reason(s) a metastatic tumor cell might lose its connection to the basal lamina would be:

the loss of integrin proteins from the cell's surface, or a change in the type of integrin proteins present on the cell's surface.

Which layer of the extracellular matrix of a plant provides the greatest strength?

the secondary cell wall

How do cells connect to the extracellular matrix?

through integrins

Which of the following cell junctions is involved in creating a barrier between cells?

tight junction