Question

the two models on the left show a glucose molecule (red and white balls) binding to the exterior of the carrier and then releasing to the inside. the ribbon model on the right shows the same carrier in a way that makes it easier to see elements of secondary structure. credit: images created by codon learning using using glut1 and pdb entry 5eq1 kapoor, piner - moore et al. (2016) mechanism of inhibition of human glucose transporter glut1 is conserved between cytochalasin b and phenylalanine amides doi.org/10.2210/pdb5eq1/pdb based on your analysis of these models, select all of the following statements that are correct. its logical to predict that the glucose binding site consists of specific r - groups, and that if a mutation changes the amino acids at the binding site, the carriers activity would change. the carrier undergoes a dramatic change in shape (or conformation) after glucose binds. the carrier should be classified as a peripheral membrane protein, because it has regions that project into the interior of the cell. the parts of the carrier that interact directly with the hydrocarbon tails inside the lipid bilayer are primarily alpha - helices. one other quick point. and this one can be extremely hard to wrap your brain around, because humans are wired to interpret events as purposeful and directed. in particular, we are extremely bad at understanding the role of randomness when we try to make sense of events. but its critically important to realize that the arrow from glucose to its binding site on the carrier—the arrow shown in the model you just analyzed—is misleading. glucose doesnt \zero - in\ the way the arrow seems to show. it isnt directed or purposeful in landing on the binding site. instead did you fully understand the concept covered in this section?

Explanation:

1. The binding site of a carrier is composed of specific amino - acid R - groups. A mutation in the amino acids at the binding site would likely change the carrier's activity as it would alter the binding properties, so this statement is correct.
2. Many carrier proteins undergo a conformational change upon binding of the ligand (in this case, glucose), which is a common mechanism for transporting substances across the membrane, so this statement is correct.
3. The carrier protein spans the lipid bilayer and is an integral membrane protein, not a peripheral one. Peripheral membrane proteins are loosely associated with the membrane, while this carrier is embedded, so this statement is incorrect.
4. The parts of integral membrane proteins that interact with the hydrophobic hydrocarbon tails of the lipid bilayer are often alpha - helices due to their hydrophobic nature, so this statement is correct.

Answer:

It's logical to predict that the glucose binding site consists of specific R - groups, and that if a mutation changes the amino acids at the binding site, the carrier's activity would change.
The carrier undergoes a dramatic change in shape (or conformation) after glucose binds.
The parts of the carrier that interact directly with the hydrocarbon tails inside the lipid bilayer are primarily alpha - helices.