Cell Growth

Why cells divide: the larger a cell become, the more demand the cell places on its DNA the cell has more trouble moving enough nutrients and wastes across the cell membrane

Large Cells DNA the information that controls a cell’s function nucleus If a cell was to grow without limits, an ‘information crisis’ would occur. Most wanted library book.

Exchanging Material Cell Membrane: Food, Oxygen, and Water enter while waste products exit. Surface Area total area of cell membrane rate of travel Cell Volume: consumption & production rates Car Doors vs. Bus Doors

Ratio of Surface Area to Volume Cell needs small surface area to volume ratio. With growth, cell volume cell increases more rapidly than surface area. Large Cells: difficult to get sufficient oxygen and nutrient in and waste products out. Small Town with a Two Lane Road

Division of the Cell Cell Division: the process by which a cell divides into two daughter cells. Before a cell divides, the DNA is copied. Each cell receives its own set of the genetic library.

Chromosomes carry genetic information made of DNA Each organism has a specific number of chromosomes. Humans: 46; Fruit Flies: 8; Carrot: 18 Before cell division, each chromosome is replicated, or copied.

Structure Each chromosome consists of two sister chromatids. The two sister chromatids are connected by a centromer. When the cell divides, the sister chromatids separate from each other. One chromatid goes to each of the two new cells.

Cell Cycle Cell Grows Prepares for Division Divides into Two Daughter Cells Cell Cycle Begins Again

Events of the Cell Cycle Interphase: long period of time G1 Phase: cell increases in size and synthesizes proteins and organelles S Phase: chromosomes replicated and synthesis of DNA G2 Phase: organelles and molecules are produced M Phase: short period of time Mitosis- division of cell nucleus Cytokinesis-division of cytoplasm