I think B. I hope this helps.
Answer:
In this case, it is likely that the polypeptide chain assumed an alpha helix configuration because the lipid bilayer did not have beta-barrel proteins.
Explanation:
A polypeptide chain is naturally polar, however, a lipid bilayer is naturally non-polar. This makes it difficult and even prevents the polypeptide chain from crossing a lipid bilayer, since the composition of these two elements does not allow them to mix. In that case, the polypeptide chain has two options to take to successfully cross the lipid bilayer.
The first option that the polypeptide chain has is to allow the creation of twisted beta sheets in the shape of a closed barrel in its structure. This only works if the lipid bilayer has beta barrel proteins in its composition to act as a transport channel for the polypeptide chain. However, few lipid layers have this protein.
Most likely, the polypeptide chain assumes an alpha helix conformation to cross lipid bilayers that do not have beta-barrel proteins. By assuming the beta conformation, the polypeptide chain reinforces the hydrogen bonds present in its composition, allowing it to cross the lipid bilayer without having its conformation and structure disassembled.
Answer:
conscious neural control
Explanation:
Neural control of digestive tract is unconscious achieved via the autonomic nervous system.
Local nervous system of the digestive system is called the enteric or intrinsic nervous system. The major components of this nervous system are two networks or plexuses of neurons:
• The myenteric plexus – controls digestive tract motility
• The submucous plexus - regulates gastrointestinal blood flow and controls epithelial cell function.
Answer:
False
Explanation:
In osmosis, water always moves from an area of higher water concentration to one of lower concentration.
