Chapter 10

Within the plant cell wall, the primary cell wall contains ______, and the secondary cell wall is composed of ______.

both pectin and cellulose; both lignin and cellulose

Cadherin is an example of:

cell adhesion molecule

Cadherins are:

cell adhesion molecules found in cell junctions.

Which structures are responsible for the shape of a cell during cell division?

They both allow direct transport of materials between cells.

Which answer choice is true about the motor proteins myosin and kinesin?

They both use the energy of ATP.

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

both intermediate filaments and microfilaments

Which cytoskeletal elements is/are associated with supporting the movement of materials inside the cell?

both microtubules and microfilaments

__________is not a cellular function of microfilaments.

Movement of motile cilia

_________is not a cellular function associated with microtubules.

Muscle contraction

Could melanin granules be moved by dynein and kinesin along an actin microfilament?

No, these motor proteins are specific to microtubules and cannot move along microfilaments.

The epidermis contains several layers and receives its nutrients from the dermis by diffusion. What 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.

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 cells of the epidermis would not be properly connected to form a water-resistant barrier.

How does the extracellular matrix affect a cell that it surrounds? Select all that apply.

The genes that the cell expresses depend in part on the types of proteins in the extracellular matrix.The cell's shape depends in part on the structure and composition of the extracellular matrix.

Suppose there is a mutation in a laminin-binding integrin gene that causes a loss of function in the cytoplasmic domains of the integrin. Which one of the outcomes would you expect to observe as a result of this mutation?

The strength of tissues would decrease because the integrin could no longer associate with microfilaments.

A patient in a physician's office has a deep cut, and as it is being stitched up, a sample of tissue is taken for testing. Analysis of the tissue reveals it has few cells, surrounded by a large amount of extracellular matrix proteins with some blood vessels, sweat glands, and nerve cells. What kind of tissue is this?

The tissue is most likely dermis, and should also have some fibroblasts, but few keratinocytes and melanocytes.

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

a component of the cytoskeleton.

Epidermolysis bullosa is a set of rare genetic disorders that is caused by:

a keratin gene that disrupts intermediate filaments, weakening connections between epidermal cell layers.

The extracellular matrix is:

a network of proteins and polysaccharides outside the cell that play a role in structural support.

Which one of the choices matches a type of cell junction with its proper cytoskeletal element and cell adhesion molecule?

adherens junction, microfilament, cadherin

A decrease in cell-cell adhesion was caused by the introduction of an experimental substance that compromised the structural integrity of the tissue. Which type of cell junction would most likely be affected by this treatment given that the treatment caused a decrease in the strength of cell-cell adhesion?

adherens junctions

A researcher is studying a population of mutant fibroblasts that fail to flatten and attach to extracellular matrix proteins on a flat surface. This is likely the result of mutations in genes encoding:

components off cell junctions

A pathologist is carrying out an autopsy. Upon opening the chest cavity, the pathologist sees a thick, fibrous tissue surrounding the heart. This is likely:

connective tissue

Which structures are responsible for the shape of a cell during cell division?

cytoskeleton

Keratinocytes are pigment cells contained in the epidermis of skin.

false

Where would you find a cell adhesion molecule?

in a cell junction

The strength of collagen comes from:

its triple helix structure and bundling

Which of the choices enable(s) the movement of cells?

microfilaments and microtubules

The internal cytoskeletal structure of cilia grows out from a structure called a basal body located near the base of the cilia. 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 type of cellular junction(s) allow(s) for the movement of proteins and transfer RNA molecules?

plasmodesmata only

Metastatic cancer cells have a dynamic actin cytoskeleton associated with their plasma membrane. The presence of the membrane cytoskeleton most likely accounts for:

the ability of these cells to move and crawl to new locations in the body.

How do cells connect to the extracellular matrix?

through integrins

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

tight junction