Copyright Pearson Prentice Hall 10–1 Cell Growth Photo Credit: © CAMR/A.B. Dowsett/Science Photo Library/Photo Researchers, Inc. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Limits to Cell Growth What problems does growth cause for cells? Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Limits to Cell Growth 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. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Limits to Cell Growth Surface area is a measure of the total area that the surface of an object occupies. The rate at which food, oxygen, water, and wastes are moved in and out of the cell is dependent on the surface area of the cell. Volume is the amount of space occupied by an object measured in three dimensions, expressed in cubic units. The rate at which food, oxygen, and water are used and waste is produced depends on the cell’s volume. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Limits to Cell Growth Ratio of Surface Area to Volume   As the length of a cell increases, its volume increases faster than the surface area (measure of total area that the surface of an object occupies). The decrease in the cell’s ratio of surface area to volume makes it more difficult for the cell to move needed materials in and waste products out quickly enough for the cell to survive. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Limits to Cell Growth Cell size is limited. If cells were too small, they could not contain all the organelles and molecules necessary for life. If cells were too large, they could not move enough materials across the membrane surface. To maintain a suitable size, cell growth and division must be coordinated. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Limits to Cell Growth As the length of a cell increases, its volume increases faster than its surface area. The resulting decrease in the cell’s ratio of surface area to volume makes it more difficult for the cell to move needed materials in and waste products out. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall As a cell becomes larger, the less efficiently it is able to function. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Division of the Cell Cells divide at different rates. The rate of cell division varies with the need for those types of cells. For example, cells that undergo more wear and tear need to reproduce more quickly. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Division of the Cell 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. Each daughter cell receives its own copy of the parent cell’s DNA. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10–1 Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10–1 As a cell increases in size, which of the following increases most rapidly? surface area volume Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10–1 If an imaginary cube-shaped cell has a length of 6 cm, its ratio of surface area to volume is 1 : 1. 6 : 1. 36 : 1. 1 : 6. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10–1 The process by which a cell divides into two new daughter cells is called cell growth. cell division. DNA replication. cell multiplication. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10–1 When one cell divides in two, what happens to the surface area to volume ratios in the new cells? There is no change in the amount of material exchanged. Each new cell can exchange more material than the original cell. Each new cell can exchange less material than the original cell. The two new cells cannot be compared to the original cell. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10–1 When a growing cell undergoes cell division, each new cell gets half the DNA from the original cell. twice as much DNA as the original cell. a random sample of the DNA in the original cell. a full copy of all the DNA in the original cell. Copyright Pearson Prentice Hall

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