2 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.
3 Limits to Cell Growth Exchanging nutrients & waste rate of using food & producing wastes depends on cell volume
4 Increased surface area to volume ratio difficult to get oxygen, food, and wastes out of the cell if the cell gets too largeExiting 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.)
5 Cell division-Cells of every organisms have a specific # of chromosomes:fruit flies = 8 humans = 46
7 Interphase The majority of time in the cell cycle G1 – cell growth, synthesize proteins and organellesS – DNA replication (copies are made) – the longest stepG2 – shortest – organelles and molecules needed for division are produced
8 InterphaseThe majority of time in the cell cycle
24 Cancer Cancer is the second leading cause of death in the U.S. Lung, colon, breast, and prostate cancers are the most prevalent types
25 CancerCancer = 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.
26 Cancer Cont. Tumor = a mass of cancer cells Benign tumors = noncancerous tumors that do not spread to other tissueMalignant tumor = cancerous tumor that invade and destroy surrounding tissueMetastasis = the spread of cancer cells
27 Causes of cancerCaused by defects in the genes that regulate cell growth and developmentSources of gene defects includetobaccoradiation exposuredefective genesviral infectionMany cancers have a defective p53 gene which halts the cell cycle until chromosomes have been replicated
28 Treatment of cancer Surgery Radiation Chemotherapy – chemical compounds that kill cancerTargets rapidly dividing cells and also interferes with cell division in normal cells (side effects)
29 10.4 Cell DifferentiationThe 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?
30 DifferentiationDuring the development of an organism, cells differentiate into many types of cells.
31 Stem CellsStem cells = the unspecialized cells from which differentiated cells developTotipotent cells= can develop into any type of cell in the bodyPluripotent = can develop into most (but not all) of the body’s cell typesInner cells in the early embryo(a hollow ball called a blastocyst)
32 Embryonic Stem CellsFound 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)
33 Adult Stem CellsAdult stem cells are multipotent. They can produce many types of differentiated cellsAdult 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
34 Stem Cell Research Repair or replace badly damaged cells and tissues. heart attackstrokespinal cord injuries.
35 Stem Cells – the ethical concerns 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 researchResearch is being done toharvest embryonic stem cells without destroying the embryoturning adult stem cells into pluripotent cellsEmbryonic stem cells out of umbilical cord bloodCord Blood Banking News ClipsCord Blood Registry Video