TEKS B.5(C) - Cancer

When cells lose their ability to regulate the cell cycle, they can divide at an accelerated rate and form a mass of cells. This mass of cells is referred to as

(a)  

• a tumor
• an embryo
• a gland
• an organ

Oncogenes are mutated forms of genes. Oncogenes can transform a cell into a tumor cell. Some tumor cells are benign, while others are malignant. How does the presence of an oncogene lead to the formation of a tumor?

• ATP production is inhibited

• Cell division is unregulated

• Somatic cell growth is inhibited

• Antibody activity is unregulated

Cells typically respond to DNA damage in three ways: by ceasing to grow and divide until the damage is repaired, by permanently ceasing to grow and divide, or by dying. In 2010 a group of scientists reported that a certain kind of immune reaction can cause DNA damage that leads to a fourth response. DNA damage can turn off genes involved in cell-signaling pathways. Turning off these genes can cause less-mature cells to divide too rapidly, often leading to the development of

(a)  

• tumors
• allergies
• hemophilia
• cardiovascular disease

Atherosclerosis is a disease that obstructs blood flow and, therefore, oxygen supply to target organs. A major component of atherosclerosis is the excessive reproduction of smooth muscle unregulated reproduction of the diseased blood-vessel cells. Which of these processes is the most likely target of these drugs?

• cell division

• erythroblast differentiation

• DNA transcription

• cellular respiration

 $$  The diagram represent the cell cycle.

When cells leave the cell cycle, they exit during G-1 phase and then enter G-0, a resting period.  Most normal cells can leave G-0 phase and reenter the cell cycle at G-1 phase before entering S phase.  

Cancer cells are different because they cannot enter G-0 phase and are likely to do which of the following?

• fail to complete S phase

• mutate during G-1 phase

• repeat the cell cycle continuously

• die after completing mitosis