Question

5. For each of the following statements, decide whether it is True or False AND provide a justification for your decision (10 points each). A. The hydrolysis of ATP is required both for the contraction and relaxation of skeletal muscles. ANSWER: B. An actin filament will grow as long as actin monomers continue to be added to the plus end. ANSWER: C. In most animal cells, dyneins transport materials to the periphery of the cell, whereas kinesins transport material to the cell's interior. ANSWER:

Answer 1

(a) Hydrolysis of ATP is required for both contraction and relaxation but ATP is needed for normal muscle contractions and as ATP reserves are reduced muscle function may decline.ATP Bins to myosin causing it to chande and attach to actin and pull causing muscle contraction . (b) yes they grow because Actin filament grow considerably faster by the reversible addition of monomers on both ends but one end it elongates 5 to 10 times faster than minus end.the assembly ,length and stability of actin filaments are controlled by specilalised ACTIN BINDING PROTEINS. (C)Kinesins moving along microtubules usually carry organells and vesicles from the centre of a cell to its periphery.where as Dyneins are important in sliding microtubules relative to one other during thebeating cilia and flagella on the surfce of the eukaryotic cells.