need u guys help?

Question

choose two and and reason plz
Biological membranes comprise both protein and lipid. Which of the following statements about membrane proteins is true?


a.Most membrane proteins are freely mobile in the plane of the membrane.

b.Integral membrane proteins are associated with the membrane via the polar surface of the bilayer.

c.Integral membrane proteins exhibit a membrane spanning hydrophobic alpha-helix of 22 amino acids.

d.Proteins perform a purely structural role in membranes.

Answer 1

I would say that "c" is definately true. Integral membrane proteins are integrated into the membrane - this is often done through a helical region that traverses the entire membrane (going through the hydrophobic core of the membrane). "B" and "D" are definately false. B, because of why C is true. D because proteins have a variety of functions - they are receptors, they are channels, they form pores, etc. I do not know if I agree that "A" is true if you have to choose two correct answers to this question. While there are definately a lot of freely mobile proteins in membranes, many are anchored to the cytoskeleton, many are part of sections of the membrane called "lipid rafts" where they are maintained and thus not really 'freely mobile'. Hope this helps.

Answer 2

e. do your own homework