BIO323 Assignment 2

Which of the following cell junctions uses cadherin cell adhesion molecules to anchor the actin cytoskeleton?

Adherens junction

How is hyaluronic acid different from other glycosaminoglycans of the extracellular matrix?

All of the above A. It lacks sulfate groups B. It is generally not covalently linked to proteins C. It is not assembled in the Golgi apparatus D. It can be several megadaltons in mass

The extracellular matrix of animals...

All of the above A. holds cells together B. contains collagen C. contains proteoglycans D. is involved in chemical signaling between cells

Which of the following is necessary for cadherins to bind homophilically?

Ca ions

Which of the following statements about collagen is false?

Collagen synthase organizes the mature collagen molecules into ordered collagen

It has been observed that cells containing a specific cadherin subtype tend to cluster together to the exclusion of other types, both in cell culture and during development. For example, cells containing _____ tend to cluster with other ______ expressing cells

N-cadherin; N-cadherin OR E-cadherin; E-cadherin

Type IV collagen molecules can interact at their C-termini to form dimers and at their N-termini to form tetramers. What category do you think this type of collagen belongs to?

Network-forming

Which of the following is NOT an anchoring junction?

Tight Junction

Which type of junction contributes the most to the polarization of epithelial cells?

Tight Junctions

Which type of collagen forms fibrils?

Type I

Which type of collagen is the most abundant in animal tissue?

Type I

Which type of collagen is mostly associated with the basal lamina?

Type IV

Proteoglycans in the extracellular matrix of animal tissues...

allow cartilage to resist compression

Skin cells are attached to the extracellular matrix by...

anchoring junctions

Selectins....

are carbohydrate-binding proteins

Aggrecan provides intervertebral disc and cartilage with the ability to resist

compression

Particularly abundant in cells of heart muscle and the epidermis, ___________ are structurally similar to adherens junctions and contain a number of homologous components. However, their cadherin molecules are linked to intermediate filaments instead of the actin cytoskeleton.

desmosomes

Structures that contain networks of keratin fibers and provide mechanical stability to epithelial tissues are called...

desmosomes

Integrins can bind cell surface and ECM components such as...

fibronectin, collagen, and laminin

Collagens are extremely rich in....

glycine and proline

Integrins are obligate ________ containing two distinct chains, called the (alpha) and (beta) subunits

heterodimers

At desmosomes, cadherin molecules are connected to...

intermediate filaments

A basal lamina...

is a thin layer of extracellular matrix underlying an epithelium

Aggrecan is a proteoglycan, which is a protein core modified with....

large polysaccharide side chains

The extracellular matrix of animal cells....

limits the cell volume by remaining rigid

Cadherins....

meditate cell-cell attachments through homophilic interactions

The main type of cell-cell adhesion molecule responsible for tissue formation are

members of the cadherin family of proteins

Fibroblasts organize the collagen of the extracellular matrix by________.

pulling the collagen into sheets or cables after it has been secreted

Cell adhesion is the binding of a cell to a surface, extracellular matrix or another cell using cell adhesion molecules such as....

selectins, integrins, and cadherins

A major distinction between the connective tissues in an animal and other main tissue types such as epithelium, nervous tissue, or muscle is....

the amount of extracellular matrix in connective tissues.

Entactin, or nidogen, is a component of _______ alongside other components such as collagen type IV, proteoglycans, laminin, and fibronectin

the basement membrane

The difference between tight junctions, desmosomes, and gap junctions is that

tight junctions and desmosomes have mechanical roles, whereas gap junctions are found in nerve cells

The alpha chains of collagen molecules are....

usually a helix with 3 amino acids per turn AND encoded by separate genes