A surgical instrument comprising: a handle assembly; a spine assembly operably coupled to said handle assembly and protruding therefrom to define a longitudinal axis; a closure tube assembly movably received on said spine assembly for selective axial travel thereon in a distal direction away from said handle assembly and in a proximal direction towards said handle assembly; a firing system operably supported by said handle assembly and interfacing with said closure tube assembly to selectively cause said closure tube assembly to move in said distal and proximal directions; and an end effector coupled to said spine assembly and having first and second jaw members (613, 615) pivotally coupled and movable relative to each other from an open position to closed positions, said first jaw member configured to support a staple cartridge therein, wherein said first jaw member has an upwardly curved first closure tip and wherein said second jaw member has a downwardly curved second closure tip such that said first and second closure tips (618, 625) form a movable scissors-like closure structure, said first and second closure tips (618, 625) configured for engagement with said closure tube assembly when said closure tube assembly is moved in said proximal direction, wherein the closure tube assembly comprises an internal distal tapered drive member comprising a tube with a tapered, distally diminishing internal diameter that is configured to interface with the scissors-like closure structure, such that when the closure tube assembly is moved in the proximal direction, the tapered drive member contacts the scissors-like closure structure to pivot the jaw members (613, 615) towards each other to said closed positions. a handle assembly; a spine assembly operably coupled to said handle assembly and protruding therefrom to define a longitudinal axis; a closure tube assembly movably received on said spine assembly for selective axial travel thereon in a distal direction away from said handle assembly and in a proximal direction towards said handle assembly; a firing system operably supported by said handle assembly and interfacing with said closure tube assembly to selectively cause said closure tube assembly to move in said distal and proximal directions; and an end effector coupled to said spine assembly and having first and second jaw members (613, 615) pivotally coupled and movable relative to each other from an open position to closed positions, said first jaw member configured to support a staple cartridge therein, wherein said first jaw member has an upwardly curved first closure tip and wherein said second jaw member has a downwardly curved second closure tip such that said first and second closure tips (618, 625) form a movable scissors-like closure structure, said first and second closure tips (618, 625) configured for engagement with said closure tube assembly when said closure tube assembly is moved in said proximal direction, wherein the closure tube assembly comprises an internal distal tapered drive member comprising a tube with a tapered, distally diminishing internal diameter that is configured to interface with the scissors-like closure structure, such that when the closure tube assembly is moved in the proximal direction, the tapered drive member contacts the scissors-like closure structure to pivot the jaw members (613, 615) towards each other to said closed positions.