DNA is extracted from human cells for a variety of reasons. With a pure sample of DNA you can test a newborn for a genetic disease, analyze forensic evidence, or study a gene involved in cancer.Try this virtual laboratory to perform a cheek swab and extract DNA from human cells.Javascript is required to view this content.ith a pure sample of DNA you can test a newborn for a genetic disease, analyze forensic evidence, or study a gene involved in cancer. Try this virtual laboratory to perform a cheek swab and extract DNA from human cells. Javascript is required to view this content.
Knee flexion means bending your leg at the knee joint, reducing the angle between your lower leg and upper leg.
Forwards flexion or bending, as of the hand or foot. For example, flexion of the foot/ankle means rotating the toes downwards (away from the leg to which the ankle and foot is attached). Bending the foot as when standing on ones toes (see video of plantar flexion).