Question

how does the gel matrix in gel electrophoresis contribute to the separation of molecules?
a. the gel is slippery and lets the molecules easily slide across it
b. the gel is sticky and prevents the molecules from moving across it
the gel matrix acts as a sieve to slow down the movement of molecules in proportion to their size.
d. the gel prevents electricity from affecting the molecules

Explanation:

Gel electrophoresis is a technique used to separate molecules. The gel matrix has a porous structure. Smaller molecules can move more easily through the pores (like a sieve), while larger molecules are slowed down more. Option A is incorrect as the gel's slipperiness is not the key factor. Option B is wrong because molecules do move across the gel. Option D is incorrect as the gel does not prevent electricity from affecting the molecules (electricity is what drives the movement of charged molecules in gel electrophoresis).

Answer:

C. The gel matrix acts as a sieve to slow down the movement of molecules in proportion to their size.