electronic switch (like MOSFET, but without diode?)
You can use a solid state relay.

TLP222AF (2 ohms, $1.08)
http://www.digikey.com/product-search/en?keywords=TLP222AF


VO14642AT (1/4 ohm, $2.66)
http://www.digikey.com/product-detail/en/vishay-semiconductor-opto-division/VO14642AT/VO14642AT-ND/4074374

Or use a regular mechanical relay.
Coto 9007-05-00 (0.2 ohms, $1.27)
http://www.digikey.com/product-detail/en/coto-technology/9007-05-00/306-1062-ND/301696