The Cell Cycle & Cellular Divisin Name: Perid: Date: I. Cell Divisin: All are derived frm preexisting cells (Cell Thery) is the prcess by which cells prduce new cells Cells grw in number, NOT in Smaller cells mre (cellular transprt, cellular cmmunicatin/signaling) t take in nutrients & get rid f wastes Hw Often D Cells Divide? Sme cells must be repaired ften such as cells lining the,, with a shrt lifespan Other cells DO NOT divide at all after birth such as, nerve cells,, II. Reasns fr Cell Divisin: Cell & f damaged cell parts Grwth and develpment f an IV. Chrmsmes & Their Structure: The plans fr making cells are cded in DNA, dexyribse nucleic acid, is a lng thin mlecule that stres DNA is rganized int giant mlecules called are made f prtein & a lng, single, tightly-ciled DNA mlecule visible nly when the cell divides When a cell is NOT dividing the chrmsme (DNA) is less visible & is called hld duplicated chrmsmes tgether befre they are separated in mitsis When DNA makes cpies f itself befre cell divisin, each half f the chrmsme is called a Each sister chrmatid cntains the genetic infrmatin 1
VI. Cell Cycle & Cell Divisin: Eukarytes (nucleus & membrane-bund rganelles) must be cpied exactly s the 2 new cells frmed frm divisin will be The riginal parent cell & 2 new must have IDENTICAL chrmsmes Ex: Humans have 46 chrmsmes in ur (bdy cells). After ne f these smatic cells ges thrugh mitsis, 2 daughter cells are prduced each having 46 chrmsmes (genetically identical). Bth the nucleus ( ) and the cytplasm ( ) must be divided during cell divisin in eukarytes Cells g thrugh phases r a cell cycle during their life befre they divide t frm new cells Cell cycle is abut hrs. fr mst animal cells Cell cycle is cntrlled by prteins and The cell cycle includes 3 main parts ---,, and = nuclear divisin = divisin f the cytplasm A. Interphase: Interphase is the part f a cell's life cycle and is called the "resting stage" because the cell isn't dividing Divided int 3 stages: 1) (Gap 1) = cell is grwing, carrying ut nrmal cell functins, preparing t replicate DNA Cells mature & increase in size by making mre & 2) (synthesis) = DNA is cpied r DNA is in the frm f (unciled DNA) and is NOT 3) (Gap 2) =cell prepares fr nuclear divisin (mitsis) cells makes all the structures needed t 2
B. 4 Stages f Mitsis: Divisin f the nucleus r ccurs first Mitsis is an methd f reprductin Only parent cell Daughter cells have SAME number f (genetic inf.) Mitsis cnsists f 4 stages --- prphase, metaphase, anaphase, & telphase 1. Prphase: phase f MITOSIS Chrmatin ( ) cndenses and cils int the frm f chrmsmes chrmsmes are visible (shaped like a X ) (half f a X ) attach t each ther by the Centriles in animal cells mve t ppsite ends f cell Spindle frms frm each centrile (ONLY in cells) cells have centriles (spindle frms frm a micrtubule) disslves (disappears) disintegrates 2. Metaphase: phase f MITOSIS Chrmsmes line up in center r f the cell the centrmere f each chrmsme attaches t spindle fibers 3
3. Anaphase: Spindle fibers attached t the centrile pull the apart at their centrmere Separated chrmsmes travel alng the t the tw ples (ends) f the cell. 4. Telphase: frms at each end f the cell arund the chrmsmes refrms Spindle fibers begin t break dwn Chrmsmes becme less tightly ciled & appear as again Cytkinesis begins Animal Cell C. Cytkinesis: = divisin f the cytplasm f the cell and its rganelles separate int 2 new daughter cells In, a grve called the frms pinching the parent cell in tw In, a frms dwn the middle f the cell where the new will be Plant Cell 4
VI. Cancer: Cell divisin must be cntrlled, therwise cell grwth will ccur withut limit (cancer) mutatins lead t changes in the prteins/enzymes that regulate the cell cycle = a cell r grup f cells that grw ut f cntrl and create a tumr Crwds ut nrmal cells and results in the lss f tissue functin = mass f grwing, unregulated cells 2 types f tumrs: 1. - tumr that des nt spread 2. - tumr that spreads and destrys healthy tissue Causes f cancer: (family histry) (cancer-causing chemicals) : HPV can lead t cancer f reprductive rgans : Sunlight- skin cancer 5