Presentation on theme: "CELL CYCLE Overview of the CHAPTER 03 and Lab BIO 211:"— Presentation transcript:
1CELL CYCLE Overview of the CHAPTER 03 and Lab BIO 211: ANATOMY & PHYSIOLOGY IBIO 211:Dr. Lawrence G. AltmanSome illustrations are courtesy of McGraw-Hill.Please wait 20 secondsbefore starting slide show.Mouse click orArrow keys to navigate.Hit ESCAPE Key to exit.
2The Cell Cycle Series of changes a cell undergoes from the time it forms until thetime it divides-Stages:interphasemitosis cytoplasmic division differentiation3-25
3The Cell Cycle the cell synthesizes new proteins and grows in size. 1. During the first growth phase, G1, (your text refers to G as "gap")the cell synthesizes new proteins and grows in size.At the end of this phase, centrioles replicate.2. During the S, or synthesis phase, the cell undergoes semiconservative replication of DNA.3. G2, the second growth phase, is a brief period in which the cell makes the enzymes needed for cell division.G1, S, and G2 are collectively known as interphase.4. During the M, or mitotic, phase, the nucleus replicates its contents (karyokinesis).
4Interphase very active period cell grows cell maintains routine functionscell replicates genetic material to prepare for nuclear divisioncell synthesizes new organelles to prepare for cytoplasmic divisionPhases:G phases – cell grows and synthesizes structures other than DNAS phase – cell replicates DNA
5Mitosis produces two daughter cells from an original cell LAB ATLAS REFERENCE:ppMorton & Perry, 1998produces two daughter cells from an original cellnucleus divides – karyonkinesiscytoplasm divides – cytokinesisStages:prophase – chromosomes form;nuclear envelope disappearsmetaphase – chromosomes align midway between centriolesanaphase – chromosomes separate and move to centriolestelophase – chromatin forms; nuclear envelope forms
7Cytoplasmic Division (CYTOKINESIS) continues through telophase begins during anaphasecontinues through telophasecontractile ring pinches cytoplasm in half (furrowing)
8Be sure to get the separate, one-page download called: MITOSIS SKETCH
9Control of Cell Division cell division capacities vary greatly among cell typesskin and blood cells divide oftenliver cells divide a specific number of times then ceasechromosome tips (telomeres) that shorten with each mitosis provide a mitotic clockcells divide to provide a more favorable surface area to volume relationshipgrowth factors and hormones stimulate cell divisionhormones stimulate mitosis of smooth muscle cells in uterusepidermal growth factor stimulates growth of new skincontact inhibitiontumors are the consequence of a loss of cell cycle control
10Tumors Two types of tumors benign – usually remains localized malignant – invasive and can metastasize; cancerousGenes that cause canceroncogenes – activate other genes that increase cell divisiontumor suppressor gene – normally regulate mitosis; if inactivated they will not regulate mitosis
11Stem and Progenitor Cells Stem cellcan divide to form two new stem cellscan divide to form a stem cell and a progenitor celltotipotent – can give rise to any cell typepluripotent – can give rise to a restricted number of cell typesProgenitor cellcommitted cellcan divide to become any of a restricted number of cellspluripotent