Exam 14: Cellular Movement: Motility and Contractility

You identify a protein that may play a role in microtubule-based transport.Propose a series of experiments that would aid you in confirming your assessment that this protein has a role in microtubule-based transport.

The "9 + 0" pattern of microtubules is associated with

Kinesin 1 is highly processive motor,taking more than 100 steps (covering 1 μm along a microtubule)before dissociating,primarily because

Crawling cells produce broad,thin protrusions known as ________ and pointed structures called ________ at the leading edge of the cell.

Eukaryotic motile cilia and flagella have similar structures but vary in number,length,and function.For each of the following,compare/contrast cilia and flagella. a.number present per cell b.length of appendage c.direction of force generated relative to the direction of the appendage d.function in unicellular and multicellular eukaryotes e.motion analogy

________ links the thick filaments to the Z line.

Arp2/3-dependent actin polymerization directly drives which of the following activities at the leading edge of crawling cells?

Which of the following would you use to inhibit the contraction of muscle in vitro as a control for an experiment you are conducting?

Which of the following lists of structures is in the correct order from inside to outside of the cell?

Axonemal dyneins are

Rigor mortis after death is caused by myosin crossbridges that fail to dissociate from the actin thin filaments because of lack of ________.

________ is the process that moves tubulin subunits to the flagellar tip where they assemble onto axonemal microtubules.

Explain why myosin II in a sarcomere can produced force only for that sarcomere contraction and not for that sarcomere extension.

In relaxed muscle,Ca2⁺ is found in highest concentration in the

In the T-tubule triad structure seen in electron micrographs of striated muscle,the T tubule is flanked by two terminal cisternae of the ________.This association facilitates opening terminal cisternae ryanodine receptors,which ________ to initiate sarcomere contraction.

Cyclosis (cytoplasmic streaming)is driven by ________ that interact with ________ that are anchored to chloroplasts near an algal cell wall.

The tetanus toxin tetanospasmin blocks release of the neurotransmitter (GABA)that inhibits motor neurons and decreases muscle contraction.This causes persistence of the signal to contract and the resulting violent muscle contraction known as tetanic spasm.Compare the sustained contraction of muscle cells in rigor mortis with muscle contraction caused by the action of tetanospasmin on motor neurons.

Which of the following major protein components of skeletal muscle is incorrectly matched with its function?

Addition of ATP to isolated axonemes causes localized bending.What can be done to the isolated axonemes to cause the outer doublets to slide past each other unrestrained,lengthening the overall structure instead of causing bending?

Myosin II is ideally suited for muscle contraction because it forms ________ filaments.