Question

Which of these statements about microtubules is true?

a) when a centrosome is present each microtubule contains a variable number of protofilaments
b) long, growing microtubules will contain GTP and GDP
c) A cell with many microtubules will not have any actin filaments
d) gamma-tubulin stabilizes microtubules minus ends by anchoring them onto a cylindrical centriole core

Answer 1

Microtubules are composed of tubulin and have various functions in a cell, including maintaining cell shape and assisting in cell division. Gamma-tubulin stabilizes microtubules by anchoring them to centrioles. Actin filaments are different from microtubules and can be present in the same cell.

Step-by-step explanation:

Microtubules are composed of two forms of tubulin, alpha and beta, which form dimers and come together to create hollow cylinders. They help the cell keep its shape, hold organelles in place, and form the mitotic spindle during cell division. Microtubules also make up parts of cilia and flagella, which aid in cell movement.

Gamma-tubulin does stabilize microtubules, but it does so by anchoring them onto a cylindrical centriole core, not by specifically stabilizing the minus ends. Actin filaments, on the other hand, are separate structures from microtubules and are present in cells along with microtubules.