Answer:
D. They float on convection currents in the mantle.
Explanation:
B. Is characterized by four different zones.
Chemosynthesis, I believe. Bacteria at the bottom of the ocean use this process for food.
Answer:
When a muscle contracts, the actin is pulled along myosin toward the center of the sarcomere until the actin and myosin filaments are completely overlapped.
Explanation:
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<h2>b) option is correct </h2>
Explanation:
- Some bacterial toxins cause disease by altering the activity of G protein, cholera toxin is one of them
- Cholera toxin catalyse ADP ribosylation of Gs and blocks GTPase activity thus Gs GTP become permanently active
- Constitutive activation of Gs protein continuously induce adenylyl cyclase, cytosolic cAMP level rises that leads to activation of protein kinase A (pKA)
- Activated pKA catalyse phosphorylation of two transmembrane proteins of intestinal epithelial cells:
- CFTR cause excessive outflow of Cl- ion and Na+ H+ exchange cause efflux of Na+ ion, both enters in gut and form Na+ Cl-
- Na+Cl- leads to outflow of water from the gut, resulting in diarrhea and dehydration and this condition may cause death of organisms due to loss of water and ions
