10-1 Cell Growth

1. 10-1 Cell Growth In most cases, living things grow by producing more cells

2. Limits to Cell Growth • The larger a cell becomes, the more demands the cell places on its DNA. In addition, the cell has more trouble moving enough nutrients and wastes across the cell membrane.

5. DNA “Overload” • When a cell is small, the information stored in its DNA is able to meet all of the cell’s needs. But as a cell increases in size, it does not make extra copies of its DNA. • If a cell were to increase without limit, an “information crisis” would occur.

7. Exchanging Materials • Food, oxygen, and water enter a cell through its cell membrane. Waste products also leave through the membrane. If the cell’s volume gets too big, the membrane won’t be big enough to allow this exchange to happen. • This is why cells must divide as they grow, to reduce the cells’ volume so it doesn’t produce too much waste.

8. Ratio of Surface Area to Volume • In a cell, volume increases much faster than surface area, causing the ratio of surface area to volume to decrease. This creates serious problems for the cell. • This is like a small town that outgrows its road system, creating too much traffic. If a cell got too large, it would be more difficult to get enough oxygen and food in and waste products out.

12. Division of the Cell • Before it becomes too large, a growing cell divides forming two “daughter” cells. The process by which a cell divides into two new daughter cells is called cell division.