Cell division is the process essential for growth and repair in multi-cellular organisms.
Injury to the tissue can activate surrounding cells to undergo cell division with the help of mitogens. Mitogens are the chemical substances which help in escalating mitotic divisions in the cells.
They act by activating the signal-transduction pathway which involve mitogen-activated protein kinase (MAPK).
Other possible manner could be the loss of density which could lead to the inactivation of contact inhibition. As there is a loss of cells during the injury, it makes an empty space which could also trigger or activate surrounding cell to start cell division.
In addition, at injury site the flow of blood also increases to transport various nutrients, clotting factors, growth factors etc. These increased nutrition and growth factors also speed up the process of mitosis.
Rough ER<span> looks like sheets or disks of bumpy membranes while </span>smooth ER<span> looks more like tubes. </span>Rough ER<span> is called </span>rough<span> because it has ribosomes attached to its surface. The double membranes of </span>smooth<span> and </span>rough ER<span> form sacs called cisternae.</span>
The most observable difference is the way in which cytokinesis occurs. In plants a new cell wall is fashioned between the new daughter cells, while in animal cells the cell membrane constricts to pinch the parent cell into daughter cells.
Answer:
C. Sprout every year, year after year
Explanation:
The perennial plants are the plants that live for more then two years, thous some may argue that they are plants that live more then three years. Whichever the case, they are not short-lived plants, but are capable of surviving for numerous years, unlike the annuals and biennials. Theoretically, the shrubs and trees would fall into this category, but they are classified separately, and this term is not used for them, but for smaller plants that do not have or have very little woody parts. These plants tend to sprout every year, and even though they seemingly die in the autumn, their roots are alive, and they emerge and grow again in the spring, sprouting again. That process repeats itself for numerous years.
