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