BIOS1610 - Chapter 10 Learning Curve

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

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, what outcome would be most likely?

cell shape and support would be affected

Which is a component of the extracellular matrix made by a plant cell but not animal cells?

cellulose

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:

component of the cytoskeleton

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 of cell junctions

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

The cell would leave the epidermis and adhere to neural cells.

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

Both microtubules and microfilaments

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

Breakdown of adherens junctions

Where would you find a cell adhesion molecule?

In a cell junction

Structures known as microvilli are associated with:

Increased surface area for nutrient absorption

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

The basal lamina:

Is a specialized extracellular matrix found beneath epithelial tissues

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

It lengthens more slowly than the plus end.

The strength of collagen comes from:

Its triple helical structure and bundling

Which statement about intracellular transport is true?

Kinesin and dynein move substances along microtubules.

Myosin is a motor protein that associates with:

Microfilaments

___________ is not a cellular function of microfilaments

Movement of motile cilia

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.

The extracellular matrix is composed of:

Proteins and Polysaccharides

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.

Which of the statements about the skin is true?

The epidermis is made up of epithelial tissue whereas the dermis is made up of primarily of connective tissue

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.

Gap junctions and plasmodesmata have what feature in common?

They both allow direct transport of materials between cells.

Cilia:

a. are used by epithelial cells to move substances along cell surfaces b. are specialized organelles found in some epithelial cells c. Can sometimes serve a sensory function

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

a. cells can control which materials are transported b. Exposure to bacteria or viruses are limited c. the exposure in internal tissues to the outside environment is limited

A benign tumor:

a. has clear boundaries encapsulating it and does not invade nearby tissues. b. is a mass of rapidly dividing cells. c. has defects in the regulation of cell division. d. Top of Form e. rarely has life-threatening effects unless it interferes with the function of a vital organ.

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

A tissue is generally composed of several organs.

false

Keratinocytes are pigment cells contained in the epidermis of skin.

false

Dynamic instability is a:

feature of microtubules

Cells with cilia rely mainly on _____ to facilitate their movement.

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 (flagella)

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

plasmodesmata only

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

they both use energy of ATP

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