Which of the following statements concerning axonal transport is FALSE O A) The polarity of microtubules helps determine the direction of transport B) Trophic substances and growth factors are taken up by the nerve terminal and transported in the retrograde direction. C) Retrograde transport uses actin filaments and anterograde transport uses microtubules. O D) Motor proteins sometimes compete for different cargoes O E) Kinesins and dyneins transport cargoes in opposite directions along microtubules

5. What would happen if tropomyosin couldn't change confirmation in the presence of Ca2+ binding to troponin? A)ACh wouldn't be released from vesicles B)Myosin couldn't bind to troponin C)Myosin couldn't bind to ATP D)Myosin couldn't bind to actin E)Ca2+ wouldn't be released from the SR

What cytoskeletal component do you think is responsible for movement of the yellow cytoplasm to the vegetal pole? A)Actin microfilaments B)microtubules C)Fibronectin

Which of the following distinguishes osmosis from simple diffusion?  a) a concentration gradient  b) a solute  c) a selectively permeable membrane  d) water molecules

Adjacent plant cells have narrow channels called plasmodesmata that pass through the cell walls of the connected cells. Which of the following statements best describes a primary function of plasmodesmata? A B с D They eliminate the need for cells to have receptors for signaling molecules. They eliminate the need to produce signaling molecules. They decrease the energy requirements for active transport. They allow the movement of nutrients and signaling molecules across adjacent cells.