Invasive aquatic species, like the zebra mussel, attach themselves to the hull of ships and are blasted off when the ships release their ballast after unloading cargo.
Answer:
- A signal for apoptosis that comes from outside the cell is when a cell detaches from extracellular matrix. If this happens, a transmembrane signal is triggered.
- Two examples of cellular occurrences that would prompt an apoptosis signal from inside the cell are:
1. Damaged DNA
2. Increase of cytosolic calcium concentration
Explanation:
Apoptosis can be activated from an intrinsic or an extrinsic pathway. The intrinsic pathway is activated when a cell senses stress (for example, damaged DNA or high cytosolic calcium concentration) and triggers death proteins to activate apoptosis mechanism inside of it; the extrinsic pathway refers to the apoptosis triggered by signals that come from other cells. In this scenario, ligands bind to cell-surface death receptors and activates a death-inducing signal.
The part of the bacteria cells that helps them stick to the surface of objects or beings is called the <span>pilus, and the pilus is found all over the surface of the bacteria.</span>