Question

what cytoskeletal element is formed from tubulin?
actin filaments
microtubules
question 6
which cytoskeletal element is important in cilia and flagella?
actin
microtubules
question 7
which is true of passive transport? (pick all correct answers)
may not require a transport protein
uses atp only when moving particles against their concentration gradient
osmosis is an example

Explanation:

• Microtubules are formed from tubulin dimers. Actin filaments are made of actin monomers.
• Cilia and flagella are composed of microtubules arranged in a 9 - 2 pattern. Actin is not the main component of cilia and flagella.
• Passive transport can occur by simple diffusion (no transport protein needed) or facilitated diffusion (needs transport protein). It does not use ATP as it moves substances along the concentration gradient. Osmosis is a type of passive transport.

Answer:

• For the first question: microtubules
• For the second question: microtubules
• For the third question: may not require a transport protein, osmosis is an example