Chapter 10 - Cell and Tissue organization

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

breakdown of adherens junctions.

Adheren junctions are composed of cell adhesion molecules called

cadherins

Desmosome are made of

cadherins and intermediate filmaments

__________________ __________________ connect cells to one another to form tissues

cell junctions

The extracellular matrix can influence __________________ __________________ and __________________ __________________.

cell shape, gene expression.

In plants the extracellular matrix is the ______________ ______________

cell wall

In plants, the extracellular matrix is found in the cell wall, and the main component of the plant cell wall is the polysaccharide __________________

cellulose

The exceptionally strong protein fiber __________________ is the primary component of connective tissue in animals

collagen

Tissue

collection of cells that work together to perform a specific funtion

Gap junctions (in animals) and plasmodemata (in plants) allows cells to

communicate rapidly with another

Where is one place microfilaments are found in abundance?

Intestinal microvilli

Two types of intermediate filaments

Keratin, lamin

Tight junctions

Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid

What would happen to a cell that depends on motile cilia for movement if it had no actin?

Nothing; motile cilia contain microtubules, not 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

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.

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.

microtubules and microfilaments are dynamic how?

They are constantly being disassembled and reassembled

Plasmodesmata are wider and larger than gap junctions. True or false?

True

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.

Amoeboids create new ______________ in the direction they want to move in

actin

Microfilaments are helical polymers of __________________ monomers

actin

Anchoring cell junctions include __________________ junctions and __________________.

adherens junctions and desosomes

Gap junctions are in animals or plants?

animals

The specialized extracellular matrix that underlies and supports epithelial cell layers is called the __________.

basal lamina

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.

In animals, the extracelluar matrix is fund in abundance in __________________ tissue

connective tissue

Keratins are found where?

cytoplasm

__________________ __________________ elements determine the shape of the cell

cytoskeletal elements

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

cytoskeleton

Anchoring cell junctions include

desmosomes and adheren junctions

Microtubules associate with the. motor proteins __________________ and __________________ to transport substances in the cell

dynein, kinesin

microtubules associated proteins

dynein, kinesin

The extracellular matrix

insoluble meshwork of proteins and polysaccharides

_________________ __________________ provide stable structural support for many types of cells

intermediate filaments

Vesicle movement of microtubule provide a track for provide a track for ______________ to walk down

kinesin

Microtubules and microfilaments are said to be "dynamic" elements of the cytoskeleton. In this case, "dynamic" means that:

microtubules and microfilaments are assembled, disassembled, and then reassembled again in a regulated manner.

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

microtubules → intermediate filaments → microfilaments

Important function of microfilaments

muscle contraction

Microfilaments associate with the motor protein __________________ to transports substances in the cell and to cause cell shape changes such as muscle contraction

myosin

Vesicle movement of microfilament provide a track for ______________ to walk down

myosin

microfilament associated proteins

mysoin

Lamins are found where?

nucleus

Plasmodesmatas are in animals or plants?

plants

Intermediate filaments

polymers of proteins that differ depending on the cell type

Microtubules are hollow polymers of __________________ dimers

tubulin