CHAPTER 10 – CELL GROWTH AND DIVISION
10.1- pg. 274-278
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Two main reasons cells divide: the larger a cell becomes, the more demands the
cell places on its DNA. In addition, a larger cell is less efficient in moving
nutrients and waste materials across the membrane.
Cell division: process by which a cell divides into two “daughter” cells. (before
cell division occurs, the cell copies all of its DNA.
Asexual reproduction: production of genetically identical offspring from a single
parent.
Sexual reproduction: type of reproduction in which cells from two parents unite
to form the first cell of a new organism.
o Offspring produced by sexual reproduction inherit some of their genetic
information from each parent.
10.2 – pg. 279-284
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Chromosomes: threadlike structure within the nucleus that contains genetic
information that is passed from one generation to the next.
o Prokaryotic Chromosome: lack nuclei; most contain a single, DNA
chromosome that contains all/nearly all genetic information
o Eukaryotic: have more DNA then prokaryotic; contain multiple
chromosomes
o Chromatin: substance found in eukaryotic chromosomes that consists of
DNA tightly coiled around histones.
Chromosomes make it possible to separate DNA precisely during cell division
Cell cycle: cell grows, prepares for division, and divides to form two daughter
cells.
PROKARYOTIC CELL CYCLE is a regular pattern of growth, DNA replication, and
cell division. This cell division is asexual reproduction known as binary fission.
EUKARYOTIC CELL CYCLE has four phases: G1, S, G2, and M.
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Interphase: period of the cell cycle between cell divisions
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G1 Phase: Cell growth
o Cells do most of the growing in this phase. Cells increase in size and
synthesize new proteins and organelles
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S Phase: DNA replication
o New DNA is synthesized when the chromosomes are replicated. By the
end of this phase the cell has twice as much DNA.
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G2 Phase: Preparing for cell division
o This is the shortest of the three phases of interphase. Organelles and
molecules required for cell division or produced.
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M Phase: Cell division
o This phase produces two daughter cells. In eukaryotes, cell division
occurs in two main stages:
 Mitosis- 1st stage- the cell nucleus divides
 Cytokinesis- 2nd stage- division of the cytoplasm
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Mitosis: divided into four stages
o Prophase: first and longest phase of mitosis in which the genetic material
inside the nucleus condenses and the chromosomes become visible.
Outside the nucleus, a spindle starts to form.
o Centromere: region of a chromosome where the two sister chromatids
attach.
o Chromatid: one of two identical “sister” parts of a duplicated
chromosome.
o Centrioles: structures in an animal cell that helps to organize cell division.
PROPHASE:
o Metaphase: second phase of mitosis in which the chromosomes line up
across the center of the cell. Spindle fibers connect the centromere of each
chromosome to the two poles of the spindle.
METAPHASE:
o Anaphase- third phase of mitosis in which the chromosomes separate and
move to opposite ends of the cells.
ANAPHASE:
o Telophase: final stage of mitosis in which the distinct individual
chromosomes begin to spread out into a tangle of chromatin
TELOPHASE:
o Cytokinesis: division of the cytoplasm to form two separate daughter cells
 This completes the process of cell division by splitting one cell
into two.
10.3 pg. 286-290
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Cyclin: one of a family of proteins that regulates the cell cycle in eukaryotic cells.
o The cell cycle is controlled by regulatory proteins both inside and outside
the cell.
 Internal regulators: respond to events occurring inside a cell.
Allow the cell to proceed only when certain events have occurred
inside the cell.
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External regulators: proteins that respond to events outside the cell.
They direct cells to speed up or slow down the cell cycle.
 Growth factors: one of a group of external regulatory
proteins that stimulate the growth and division of cells.
Apoptosis: process of programmed cell death
o Once triggered, cells undergo a series of steps that lead to destruction.
Cancer: disorder in which body cells lose the ability to control growth.
o Cancer cells do not respond to the signals that regulate the growth of most
cells. As a result, the cells divide uncontrollably.
Tumor: mass of rapidly dividing cells that can damage surrounding tissue.
10.4- pg. 292-297
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Embryo: developing stage of a multicellular organism
Differentiation: process in which cells become specialized in structure and
function
o During the development of an organism, cells differentiate into many
types of cells.
Totipotent: cells that are able to develop into any type of cell found in the body.
Human development:
 Blastocyst: stage of early development in mammals that consists of a hollow ball
of cells.
 Pluripotent: cells that are capable of developing into most, but not all, of the
body’s cell types.
 Stem cells: unspecialized cell that can give rise to one or more types of
specialized cells.
o Multipotent: cell with limited potential to develop into many types of
differentiated cells.
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Human embryonic stem cell research is controversial because the arguments for it
and against it both involve ethical issues of life and death.