limits to cell growth dna overload creates an information crisis… library analogy, everybody...
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Limits to Cell Growth DNA overload
creates an information crisis…
Library analogy, everybody rushing to the library to checkout one of 5 copies of a book.
Limits to Cell Growth Exchanging nutrients & waste
rate of using food & producing wastes depends on cell volume
Increased surface area to volume ratio
difficult to get oxygen, food, and wastes out of the cell if the cell gets too large
Exiting the CHS parking lot at 3:10 pm is hard because there are only 2 outlets (small surface area and a large volume of people trying to leave.)
Cell division -Cells of every organisms have a specific # of chromosomes:
fruit flies = 8 humans = 46
Interphase The majority of time in
the cell cycleG1 – cell growth,
synthesize proteins and organelles
S – DNA replication (copies are made) – the longest step
G2 – shortest – organelles and molecules needed for division are produced
InterphaseThe majority of time in the cell cycle
Mitosis
Division of the nucleus (Whitefish )
Prophaselongest phase of
mitosis (50-60%)
chromosomes visible
nuclear membrane breaks apart
spindle formscentrioles
separate
Metaphasechromosomes line
up
each chromosome connected to a spindle fiber
Anaphase
sister chromatids separate
TelophaseBegin to see
cell membrane (cell plate) formbetween cells
Nuclear membrane forms
Cytokinesisthe division of the cytoplasm (2 daughter cells)
Mitosis animation-Hybrid
http://www.youtube.com/watch?v=VGV3fv-uZYI
Abnormal Cell Growth
Abnormal Cell Growth
A Large Abdominal Tumor
Surgical Removal of Tumor
Surgical Removal of Tumor
Body without Tumor
CancerCancer is the second leading cause of death
in the U.S.Lung, colon, breast, and prostate cancers are
the most prevalent types
Cancer = occurs when some of the body’s cells lose the ability to control growthCancer cells do not respond to the signals that
regulate growth and divide uncontrollablyCancer cells absorb nutrients needed by other
cells, block nerve connections, and prevent organs from functioning.
Tumor = a mass of cancer cellsBenign tumors =
noncancerous tumors that do not spread to other tissue
Malignant tumor = cancerous tumor that invade and destroy surrounding tissue
Metastasis = the spread of cancer cells
Caused by defects in the genes that regulate cell growth and development Sources of gene defects include
tobacco radiation exposure defective genes viral infection
Many cancers have a defective p53 gene which halts the cell cycle until chromosomes have been replicated
Surgery Radiation Chemotherapy – chemical compounds that
kill cancerTargets rapidly dividing cells and also
interferes with cell division in normal cells (side effects)
The human body contains hundreds of different cell types, and every one of them develops from the single cell that starts the process. How do the cells get to be so different from each other?
During the development of an organism, cells differentiate into many types of cells.
Stem cells = the unspecialized cells from which differentiated cells develop
Totipotent cells= can develop into any type of cell in the body
Pluripotent = can develop into most (but not all) of the body’s cell typesInner cells in the early embryo (a hollow ball called a blastocyst)
Found in the inner cells mass of the early embryo.
Embryonic stem cells are pluripotent. (cells have the capacity to produce most cell types in the human body)
Adult stem cells are multipotent. They can produce many types of differentiated cells
Adult stem cells of a given organ or tissue typically produce only the types of cells that are unique to that tissue.
Peyton Manning Stem Cells?????Skin Cell Spray
Repair or replace badly damaged cells and tissues.heart attackstrokespinal cord injuries.
Embryonic stem cells are harvested from early embryosMost methods destroy the embryoIn the past, US limited funding for the embryonic
cell lines used for research - NIH has136 embryonic stem lines in the US that are currently being used for research
Research is being done to harvest embryonic stem cells without destroying the
embryo turning adult stem cells into pluripotent cells Embryonic stem cells out of umbilical cord blood
Cord Blood Banking News Clips Cord Blood Registry Video
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