The aerodynamic shape and lightness of the blue shark body allow it
to move “elegantly” across the oceans. It exhibits countershading like
many other sharks. The upper part is an indigo blue tone while the
ventral and the sides are white.
It has a long caudal heterocercal fin. The second dorsal fin measures
almost half the size of the first and its pectoral fins are unusually
long compared to other sharks. Its eyes are large, its teeth are
triangular, and it has a conical snout.
It reaches a length ranging from 3.8 to 4 meters and weighs about 240
kilograms. This species presents slight sexual dimorphism since the
female tends to measure little more than 1 meter in comparison with the
male.
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.
Answer:
1 evolution 2 natural selection.
Explanation:
Answer:
D -herbivore population sizes decrease ,then the carnivore population sizes decrease