Chapter 9, Problem 39A

Summary Introduction

To predict:

Why too- frequent or too- infrequent apoptosis could endanger health

Introduction:

Cell division and apoptosis are two very important aspects of growth and development of an organism. Cell division helps in growth and repair of tissues. Apoptosis refers to programmed death of cells which results in decrease in number of cells. A series of events lead to complete destruction of cells undergoing apoptosis. This helps in preventing tumors from developing and forming cancers.

Answer to Problem 39A

Apoptosis is a cell response to DNA damage that results in cell death. If it occurs too frequently it may kill many innocent cells and weaken the organism. If it occurs too infrequently it may lead to development of cancer.

Explanation of Solution

Apoptosis refers to programmed death of cells which results in decrease in number of cells. This phenomenon may be triggered by some internal and external factors. It may occur in cells that are damaged beyond repair, including cells with DNA damage that could lead to cancer. Cancer occurs when the normal cell cycle is disrupted and the cell does not respond to control mechanisms. Cancer is uncontrolled growth and division of cells. These unchecked cancer cells can even kill the organism by crowding out normal cells.

Apoptosis helps in preventing tumors from developing and forming cancers. If apoptosis occurs in quick succession it will kill healthy cells also. This will endanger the life of an organism. If apoptosis is delayed or is infrequent, it may lead to cancer as it will not kill the damaged cells at right time thereby allowing tumors to grow.