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