Biology · Principles and Processes in Biotechnology

Why are single-stranded overhanging stretches created by restriction endonucleases called 'sticky ends'?

1. They covalently bind to agar matrix during gel electrophoresis.
2. They form hydrogen bonds with their complementary cut counterparts.
3. They permanently bind to ethidium bromide stain molecules.
4. They automatically circularize DNA without requiring ligase enzyme.