#Question id: 1378
#Unit 4. Cell Communication and Cell Signaling
Which of the following apply to fibronectins? Please select all that apply.
a) They are disulphide linked dimers, with each polypeptide composed of a number of binding domains joined together by short flexible segments.
b) They have an essential role in linking the extracellular matrix to its underlying cells.
c) Like integrins, fibronectins are directly connected to the cytoskeleton.
d) They participate in 'inside out' and 'outside in' signalling mechanisms.
#Question id: 1379
#Unit 4. Cell Communication and Cell Signaling
Which of the following statements apply to cellulose? Please select all that apply.
a) It is a polyglucose containing beta 1-6 glycosidic bonds.
b) It is a major component of plant cell walls
c) It is a polyglucose containing beta 1-4 glycosidic bonds.
d) It is a major component of Gram negative cell walls.
#Question id: 1380
#Unit 4. Cell Communication and Cell Signaling
Which of the following apply to the synthesis of plant cell walls? Please select all that apply.
a) Cellulose microfibrils are formed by cellulose synthase complexes called rosettes
b) Cellulose is synthesized using cytoplasmic ATP-glucose and deposited as microfibrils directly on the outer surface of the plasma membrane.
c) Matrix polysaccharides of plant cell walls are synthesized in the Golgi apparatus and exported to the cell wall by endocytosis.
d) The direction of cellulose microfibril growth is determined by the orientation of arrays of microtubules lying just below the plasma membrane.
#Question id: 1381
#Unit 4. Cell Communication and Cell Signaling
Match each definition with given terms
|
1. Large family of structurally related, secreted, dimeric proteins that act as hormones and local mediators to control a wide range of biological functions in all animals. |
A. Rho |
|
2. Cell-surface receptor in which the cytoplasmic domain either has enzymatic activity itself or is associated with an intracellular enzyme. |
B. TOR pathway |
|
3. A crucial signaling protein in the PI-3-kinase–Akt signaling pathway, so named because it is the target of rapamycin. |
C. Enzyme-coupled receptor |
|
4. A kinase that is involved in intracellular signaling pathways activated by cell-surface receptors and that phosphorylates inositol phospholipids at the 3 position of the inositol ring. |
D. Phosphoinositide 3-kinase |
|
5. A group of monomeric GTPases that regulate both the actin and microtubule cytoskeletons. |
E. (TGFβ) superfamily |
|
6. Cytoplasmic tyrosine kinase present at cell–matrix junctions in association with the cytoplasmic tails of integrins. |
F. Focal Adhesion Kinase |
#Question id: 1382
#Unit 4. Cell Communication and Cell Signaling
Following statements are regarding to cell-cell and cell–extracellular matrix junctions and their adhesion molecules.
A. Adherens junctions and desmosomes are integrin-containing anchoring junctions that bind the membranes of adjacent cells, giving strength and rigidity to the entire tissue.
B. Hemidesmosomes are cadherin-containing anchoring junctions that attach cells to elements of the underlying extracellular matrix.
C. Integrins are a large family of αβ heterodimeric cell-surface proteins that mediate both cell-cell and cell-matrix adhesions and inside-out and outside-in signaling in numerous tissues.
D. Tight junctions block the diffusion of proteins and some lipids in the plane of the plasma membrane, contributing to the polarity of epithelial cells. They also limit and regulate the extracellular (paracellular) flow of water and solutes from one side of the epithelium to the other.
Which of the following statements are incorrect?
#Question id: 1383
#Unit 4. Cell Communication and Cell Signaling
Match the following correctly
