Chapter 10 Biology

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.

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

breakdown of adherens junctions.

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

cell adhesion molecules are species specific

List the following in order from lesser to greater complexity: organs, tissues, and cells.

cells, tissues, organs

What would you expect to find within connective tissue?

collagen fibroblasts elastin polysaccharides

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

They both use the energy of ATP.

Motor proteins cause movement by:

binding to the cytoskeleton. undergoing a conformational change. harnessing energy from ATP.

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

Both intermediate filaments and microfilaments

If intermediate filaments were capable of dynamic instability, what outcome would be most likely?

Cell shape and support would be affected.

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

It lengthens more slowly than the plus end.

Which statement about intracellular transport is true?

Kinesin and dynein move substances along microtubules.

_________ could be a part of the extracellular matrix made by a plant cell.

Lignin

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.

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.

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.

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.

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.

Gap junctions and plasmodesmata have what feature in common?

They both allow direct transport of materials between cells.

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

a change in the integrin proteins from the cell's surface.

An epithelial tissue is defined as:

a collection of cells that lines cavities or outside surfaces.

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.

Evidence that cytoskeletal elements have ancient origins comes from the:

ability to form functional hybrid microfilaments from actin monomers taken from distantly related organisms. observation that both prokaryotes and eukaryotes use cytoskeletal elements to assist cell division. sequence similarities of cytoskeletal elements when comparing distantly related organisms.

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 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

Keratinocytes are pigment cells contained in the epidermis of skin.

false

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

Which type of cytoskeletal element is present in animal cells but absent from plant cells?

intermediate filaments

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

microtubules

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

microtubules and microfilaments

Which is the correct decreasing order of cytoskeletal elements from largest filament diameter to smallest filament diameter?

microtubules → intermediate filaments → microfilaments

Which of the choices correctly lists the sequence in which the plant cell wall is synthesized?

middle lamella → primary cell wall → secondary cell wall

Which structures are located in the dermis of the skin?

nerve endings connective tissue sweat glands blood vessels

Epithelial tissue is found:

on the outer surface of the body. lining blood vessels. lining the lungs. lining the gastrointestinal tract.