#Question id: 2946
#Unit 2. Cellular Organization
Which of the following occurs during anaphase A?
#Question id: 10610
#Unit 10. Ecological Principles
Among the following which statement is false about r-selected species?
#Question id: 995
#Unit 1. Molecules and their Interaction Relevant to Biology
Saturated fatty acids are degraded by the stepwise reactions of B oxidation, producing acetyl-CoA. Under aerobic conditions, how many ATP molecules would be produced as a consequence of removal of each acetyl-CoA?
#Question id: 899
#Unit 1. Molecules and their Interaction Relevant to Biology
Which statement is true about disulfide bonds and protein folding?
#Question id: 1387
#Unit 4. Cell Communication and Cell Signaling
The ability of a population of fibroblasts to migrate along the surface of a tissue culture dish depends on adhesion between the cell surface and the extracellular matrix molecules coating the dish. The dish is coated with laminin, and the only cell-surface protein capable of binding laminin is a cell-adhesion protein called an integrin. Integrins are integral plasma-membrane proteins that function as heterodimers. Under these conditions the rate at which a fibroblast can migrate along the laminin coated culture dish is proportional to the strength of adhesion between the cell and the laminin substrate. The table below lists the rate of cell migration observed for fibroblasts genetically engineered to generate the indicated phenotypes. Microinjection into the cytoplasm of a wild. type cell of a solution of a synthetic peptide possessing the same sequence as the integrin beta subunit cytoplasmic domain would be expected to yield an average fibroblast-cell migration rat
|
Fibroblast
Phenotype |
Level of
Integrin Heterodimer at the Cell Surface (percent of wild type) |
Rate of
Cell Migration (pm/min) |
|
1. Wild type |
100 |
2 |
|
2.
Overexpression of the wild-type integrin alpha subunit |
104 |
2 |
|
3. Overexpression
of an integrin beta subunit lacking the cytoplasmic domain |
96 |
0.6 |
|
4.
Overexpression of the soluble cytoplasmic domain of an integrin beta subunit |
98 |
0.6 |
|
5. Absence of
the integrin alpha subunit |
Less than 1 |
0.05 |