Answer:
b. Inhibiting the activity of adenylyl cyclase in the cell.
Explanation:
Cholera toxin enters the interstitial epithelial cells with the help of 5 identical B sub units and 1 A sub unit. A sub unit is catalytic and it is endocytosed in interstitial epithelial cells. Inside cells, A sub unit is cleaved into two fragments A1 and A2 with the help of proteases. A1 upon interaction with a small cytosolic G protein named as ARF-6 activates Gsα protein permanently by post translation modification known as ribosylation. This Gsα protein further acts upon an intracellular adenylate cyclase. The adenylate cyclase constitutively produces cyclic AMP (cAMP) which acts upon CFTR chloride ion channel and Na⁺ and H⁺ exchanger. As a result of this, large efflux of NaCl occurs. After NaCl loss, inside condition becomes hypotonic which leads to loss of water from the cells. This condition causes diarrhea .
But if activity of adenylate cyclase can be inhibited, the signaling cascade will come to an end leading to reduced harmful effect of cholera toxin.
Explanation:
The evolution of bacteria has progressed over billions of years since the Precambrian time with their first major divergence from the archaeal/eukaryotic lineage roughly 3.2-3.5 billion years ago. This was discovered through gene sequencing of bacterial nucleoids to reconstruct their phylogeny.
I believe it is "C. Cotton sheets" because cotton is a renewable resource and since it is a sheet it is sure to be entirely made of cotton