Question

Cellular biology answer check. please check if my answers arecorrect or not.

1) The concentration of ions inside a cell is the same as theirconcentration outside of the cell. True or false? (i chose falsesince having equilibrium inside a cell is bad)

2) Membrane transport proteins...

a)...transport membrane potentials between cells

b)	...transport membranes from the ER to the Golgi

c)	...are made up of phospholipids

d)	...transport molecules across membranes

i chose d

3)The electrochemical gradienttakes into account:

a)	The concentration of solutes on either side of themembrane.

b)	The overall charge on either side of the membrane.

c)	Both of these.

i chose C. (although i am sure that overall charge matters, Iwasn't sure if concentration of solutes are taken account.)

4) If no energywere expended by an animal cell:

a)	Both gradients would be depleted

b)The K+ gradient would maintain itself.

c)	None of these

d)	The Na+ gradient would maintain itself.

I chose d) mainly because I think Na+ gradient exist in animalcell and not K+ gradient.

5) Which of the following is a true statement aboutactin?

a)	Once actin has polymerized, it never depolymerizes.

b)	Actin is a transmembrane protein.

c)	Actin can form branched networks.

d)	Actin filaments are organized into hollow tubes.

I chose c. can't explain why.

6)Ion channels:

a)	Form a hydrophobic channel through the membrane

b)	Have filters that let sugars through

c)	Are selective for particular ions (only the