Since RNA is single-stranded, it can fold upon itself and form structures that are protein-like in both appearance and functionality.
AP Biology (2012–13)
1.B.1.a , 3.A.1.a,b,c , 4.A.1.a,b
IB Biology (2009)
3.4.1-3.4.3, 3.5.1-3.5.5, 7.2.1-7.2.3, 7.3.1-7.3.4, 7.4.1-7.4.4, 7.4.6, 7.4.7
NGSS (April 2013)
HS-LS1-1 (LS1.A), HS-LS3-1 (LS3.A), HS-LS4-1 (LS4.A)