An end effector assembly (300, 400) configured for use with a surgical instrument or surgical system, the end effector assembly (300, 400) comprising: first and second jaw members (310, 320, 410, 420) each including an outer jaw housing (312, 322, 412, 422), a tissue-treating plate (314, 324, 414, 424), and a longitudinally-extending channel (315, 325, 415, 425) defined therethrough, at least one of the first or second jaw members (310, 320, 410, 420) pivotable relative to the other between a spaced-apart position and an approximated position; and a cutting mechanism (330, 430), including: an activation member (332, 434) extending longitudinally through at least a portion of the longitudinally-extending channel (325, 425) of the second jaw member (320, 420), the activation member (332, 434) configured to move from a substantially linear configuration to an arced configuration; and a knife (338, 432) disposed on the activation member (332, 434), wherein, in the substantially linear configuration of the activation member (332, 434), the knife (338, 432) is fully disposed within the longitudinally-extending channel (325, 425) of the second jaw member (320, 420), and wherein, in the arced configuration of the activation member (332, 434), the knife (338, 432) extends transversely from the longitudinally-extending channel (325, 425) of the second jaw member (320, 420), between the first and second jaw members (310, 320, 410, 420), and at least partially into the longitudinally-extending channel (315, 415) of the first jaw member (310, 410). first and second jaw members (310, 320, 410, 420) each including an outer jaw housing (312, 322, 412, 422), a tissue-treating plate (314, 324, 414, 424), and a longitudinally-extending channel (315, 325, 415, 425) defined therethrough, at least one of the first or second jaw members (310, 320, 410, 420) pivotable relative to the other between a spaced-apart position and an approximated position; and a cutting mechanism (330, 430), including: an activation member (332, 434) extending longitudinally through at least a portion of the longitudinally-extending channel (325, 425) of the second jaw member (320, 420), the activation member (332, 434) configured to move from a substantially linear configuration to an arced configuration; and a knife (338, 432) disposed on the activation member (332, 434), wherein, in the substantially linear configuration of the activation member (332, 434), the knife (338, 432) is fully disposed within the longitudinally-extending channel (325, 425) of the second jaw member (320, 420), and wherein, in the arced configuration of the activation member (332, 434), the knife (338, 432) extends transversely from the longitudinally-extending channel (325, 425) of the second jaw member (320, 420), between the first and second jaw members (310, 320, 410, 420), and at least partially into the longitudinally-extending channel (315, 415) of the first jaw member (310, 410). an activation member (332, 434) extending longitudinally through at least a portion of the longitudinally-extending channel (325, 425) of the second jaw member (320, 420), the activation member (332, 434) configured to move from a substantially linear configuration to an arced configuration; and a knife (338, 432) disposed on the activation member (332, 434), wherein, in the substantially linear configuration of the activation member (332, 434), the knife (338, 432) is fully disposed within the longitudinally-extending channel (325, 425) of the second jaw member (320, 420), and wherein, in the arced configuration of the activation member (332, 434), the knife (338, 432) extends transversely from the longitudinally-extending channel (325, 425) of the second jaw member (320, 420), between the first and second jaw members (310, 320, 410, 420), and at least partially into the longitudinally-extending channel (315, 415) of the first jaw member (310, 410).