frogs,toads,snakes,lizards
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.
ATP
Explanation:
ATP is produced in the cells and its conversion to energy is a single-step process.
The OECD found that the responsiveness of housing supply to demand in the UK was the weakest among developed countries, due in large part to green belt policies. The green belt concept was first introduced for London in 1938 before the 1947 Town and Country Planning Act enabled local authorities to designate the status themselves. The policy was introduced to contain urban sprawl following huge post-war housing developments, and expanded greatly between 1951 and 1964. Since 1979, the green belt has doubled to cover 13 per cent of land in England (while only 2.3 per cent is covered by buildings).
