Cell Growth and Division Chapter 10
Limits to cell growth 10-1 1. The larger a cell becomes, the more demands the cell places on its DNA. 2. The more trouble the cell has moving enough nutrients and wastes across the cell membrane.
DNA overload DNA controls the cell’s function When a cell is small, the information stored in that DNA is able to meet all of the cell’s needs. As the cell increases in size, it does not make extra DNA and is no longer able to serve the needs of the growing cell.
Exchanging materials Cells must obtain all of their food, oxygen and water through their membrane The rate at which food and oxygen are used up and waste produced depends on the cell’s volume As cells grow large their ability to obtain materials through their membrane goes down Surface area to volume ratio
Ratio of Surface Area to Volume in Cells Section 10-1 Cell Size Surface Area (length x width x 6) Volume (length x width x height) Ratio of Surface Area to Volume As cell volume increases, surface area decreases! Go to Section:
How does the cell handle overload??
Cell Division 10-2 DNA is stored in the form of chromosomes Human cells contain 46 chromosomes Fruit flies contain 8 chromosomes C. not visible except during cell division Each C. is replicated prior to division What you see is identical “sister” chromatids Chromatids are attached in the center by a centromere
Chromosomes
Cell Cycle Period of time from the beginning of one cell division to the beginning of the next. G1 phase – cell growth and activity S phase – replication G2 – time gap M phase – mitosis Interphase – G1, S, G2
Figure 10–4 The Cell Cycle Section 10-2 G1 phase M phase S phase Go to Section:
Mitosis The process by which the chromosome’s in a cell duplicate themselves and then separates into two identical cells. Mitosis is the division of body cells (somatic cells) 4 stages of mitosis
Interphase Normal cellular function DNA get replicated Cell prepares for cell division Chromosomes are not visible
Prophase DNA begins to coil up Chromosomes become visible Nuclear membrane dissolves Centrioles move to opposite ends
Metaphase Chromosomes meet in the middle
Anaphase Chromosomes pull apart
Telophase Cell membrane pinches in (animal cell) Cell wall begins to form in (plant cells) Cytokinesis
Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:
Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:
Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:
Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:
Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:
Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming Go to Section:
Interphase
Prophase
Metaphase
Anaphase
Telophase
Telophase
Prophase
Metaphase
Anaphase
Telophase