But in test-tube experiments the mock DNA couldn't pierce the membrane of human cells.

FORBES: Antisense and Sensibility

Test your home with a mock break-in: If you were a burglar, how would you get in?

CNN: ASIANOW - TIME Money | Keeping It Safe | 11/99

Mock exams like these are one way test companies try out questions for future exams, but they have increasingly come under fire from parents, educators and politicians pushing back against the expansion of standardized testing.

WSJ: Test Maker Pays New York State Students to Take a Trial Exam

Its engineers recently torched 4, 000 tires at once to test the sprinkler heads in a mock BFGoodrich warehouse.

FORBES: By the Numbers

Friday's successful advanced missile defense test, which shot down a mock nuclear warhead in space, shows that the US is getting closer to defending the country against ballistic missile attack.

CENTERFORSECURITYPOLICY: Center For Security Policy

It is led by the Department for Environment, Food and Rural Affairs (Defra) and brings together 10 government departments, 34 local resilience forums, emergency responders, water companies, hospitals and schools to test responses to a range of mock flood situations over four days from Monday.

BBC: Thames Valley, Surrey and London flood plan tested

Regional development minister Danny Kennedy answered a number of questions relating to water supply, including Exercise Watermill, a mock incident exercise held in October 2011 to stress test Northern Ireland Water's response capacity.

BBC: Question Time: OFMDFM and Regional Development