Biology, 06.12.2021 17:10 krandall232
The survival, , and size of each cell in an animal are controlled by extracellular signal molecules secreted by neighboring and distant cells. Many of these signal molecules bind to a cell-surface and trigger various intracellular signaling pathways. one class of signal molecules, called , stimulates cell division by releasing the molecular brakes that keep cells in the or phase of the cell cycle. Members of a second class of signal molecules are called , because they stimulate cell growth and an increase in cell mass. The third class of signal molecules, called , inhibits by regulating members of the family of proteins. In addition to such stimulatory factors, some signal proteins such as act negatively on other cells, inhibiting their survival, growth, or proliferation.
Answers: 3
Biology, 22.06.2019 02:00
1. emigration the movement of people from one place to another 2. immigration a situation in which resources are being used up at a faster rate than they can be replenished 3. migration the leaving of one's homeland to settle in a new place 4. overpopulation the movement of people to a new country 5. sustainable development a situation in which the birth rate is not sufficient to replace the existing population 6. underpopulation the ability to meet current needs without reducing the ability to meet future needs 7. unsustainable development the increase in the population of a city 8. urbanization a situation in which the number of people exceeds the available natural resources in an area
Answers: 2
Biology, 22.06.2019 13:20
Where is the nictitating membrane found? a. between the eyelid and the eyeball b. between the retina and the optic nerve c. between the outer and middle ear d. in the organ of corti in the middle ear
Answers: 2
The survival, , and size of each cell in an animal are controlled by extracellular signal molecules...
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