Pandas live for about 20 or so years
Because migration and and other seasonal movements can affect the possibility of finding a mate, stresses, that could affect offspring survival(can vary with season), and also availability of thing that are available for the offspring.
Answer:
1. Inhibiting IP3 channels, leading to decreased Ca2 in the sarcoplasm and reduced contraction.
2. Increasing the relative activity of MLCP, leading to a decrease in tension.
3. Activating K channels, increasing K leaking out of the cell which hyperpolarizes it and decreases the likelihood of Ca2 entry.
Explanation
In smooth muscle, cyclic AMP (cAMP) mediates relaxation because cAMP inhibits a specific kinase required for myosin light chain protein (MLCP) phosphorylation, thereby triggering contraction in the smooth muscles. It has been shown that cAMP inhibits 1,4,5-trisphosphate (IP3)-dependent calcium ions (Ca 2+) release by activation of the cGMP-dependent protein kinase (PKG). PKG proteins act to modulate Ca2+ oscillations by stimulating sarcoplasmic Ca2+-ATPase membrane proteins, increasing Ca2+ in the sarcoplasmic reticulum stores and Ca2+ efflux from the cells, and activate voltage-gated potassium (K) channels, thereby leading to membrane hyperpolarization and reducing Ca2+ entry through Ca2+ channels.
Facilitated diffusion
<span>The word 'diffusion' means free movement across distance, with or without the presence of a barrier. However, there is a phenomenon known as facilitated diffusion which occurs at the cellular level. The cell does not allow free radicals and other harmful substances to enter and harm the cell organs. This is possible due to the structure of the cell membrane. The structure is such that, it allows only certain things to pass in and out of the cell. One such activity that allows selective movement in and out of the cell is the process of facilitated diffusion.</span>
