AP BIOLOGY

Detailed explanation-1: -In summary, cancer cells have defects in normal cellular functions that allow them to divide, invade the surrounding tissue, and spread by way of vascular and/or lymphatic systems. These defects are the result of gene mutations sometimes caused by infectious viruses.

Detailed explanation-2: -Most cancer-causing DNA changes occur in sections of DNA called genes. These changes are also called genetic changes. A DNA change can cause genes involved in normal cell growth to become oncogenes. Unlike normal genes, oncogenes cannot be turned off, so they cause uncontrolled cell growth.

Detailed explanation-3: -Cancer cells ignore signals from other cells Cells send chemical signals to each other all the time. Normal cells obey signals that tell them when they have reached their limit and will cause damage if they grow any further. But something in cancer cells stops the normal signalling system from working.

Detailed explanation-4: -Cells with too many mutations may stop working normally, grow out of control and become cancerous. It can take many years for cells to build enough damage to become cancer. Gene mutations that build up in cells are called “acquired” or “somatic” mutations.