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.
Definition/description. A flexion deformity of the knee is the inability to fully straighten the knee. A synonym for it is flexion contracture. Normal active range of motion of the knee is 0Â° extension and 140Â° flexion. In people with a flexion deformity one of them or both are reduced.efinition/description. A flexion deformity of the knee is the inability to fully straighten the knee. A synonym for it is flexion contracture. Normal active range of motion of the knee is 0Â° extension and 140Â° flexion. In people with a flexion deformity one of them or both are reduced.