Chapter 10-Cell Growth & Division

Chapter 10-Cell Growth & Division/Ch.11 iv.-Meiosis

I. Cell Growth A.Limits to Cell Growth o 2 reasons cells divide rather than continuing to grow indefinitely: 1)larger a cell grows,the more demands on its ______➪ will not be making enough copies of DNA as size increases---This would cause an information crisis. 2)difficult to move waste and nutrients across cell ➪ rate @ which waste products leave cell depends on ______of cell=total area of cell membrane ➪ rate @ which food and Oxygen are used up and waste produced depends on ______➪ RATIO OF SURFACE AREA TO VOLUME- assuming a cube shape,surface area=l x w x 6…..volume= lx w x h…. ratio = SA /volume

See p.243

➪ Volume increases faster than surface area/CAUSING RATIO TO ______..causing serious problems for cell.

1 B.Division of Cell ➪ A cell divides into 2 daughter cells =______➪ This happens before a cell can get too large ➪ DNA ______before cell division,solving info crisis. II. Cell Division ***simpler in prokaryotes A.chromosomes –carries genetic info in eukaryotes ➪ made up of ______and proteins ➪ cells of every organism have a specific # of Chromosomes ➪ humans have___ Chromosomes ➪ fruit flies have 8 ➪ usually not visible except in cell division,when they condense ➪ ______before cell division ➪ each Chromosome consists of 2 identical ______, which separate from each other in cell division ➪ chromatids attached @______, usually near middle

B.Cell Cycle ➪ ______is in- between phase

2 ➪ ______is the series of events that a cell goes through during growth and division….Where the cell grows,prepare for division,divides into 2 daughter cells ➪ 4 phases 1)M= ______2)S= ______3)G1 and G2= ______

Label diagram above-see p.245

3 C.Mitosis-4 phases

***Label ANAPHASE above ______

1.Prophase ➪ Longest phase ➪ Chromosomes become visible

4 ➪ ______,2 tiny structures near nuclear envelope- separate and take positions on opposite ends of nucleus ➪ Centrosome region helps organize ______- microtubules that help separate chromosomes ➪ Chromosomes attach to ______➪ @ end chromosomes coil tightly and nuclear envelope disappears 2.Metaphase- . chromosomes line up @ center . Centromeres go to 2 poles 3.Anaphase- . Centromeres split . Chromatids separate and become individual ______➪ New chromosomes go to opposite poles and then stop moving 4. Telophase- ➪ Chromosomes disperse into tangle of material ➪ New nuclear envelopes ➪ Spindle breaks apart ➪ Nucleolus becomes visible

D.Cytokinesis-divison of cytoplasm o Usually along w/ Telophase o Cell plate forms in plants that becomes the ______III.

5 o ______= disorder in which some of the body’s cells lose the ability to regulate growth o They do not respond to signals that regulate growth o Divide uncontrollably,making ______(masses of cells) o ______=protein that regulates normal cell cycle (in eukaryotes)

Chapter 11 notes-MEIOSIS ONLY

IV. MEIOSIS  Mendel’s principles require 2 things-1)each organism inherits a single copy for every gene from each parent.  When an organism produces its own gametes,those 2 sets of genes must be separated from each other so that each gamete has only 1 set. A. Chromosome #  The sets of chromosomes will be homologous,meaning that one from male corresponds w/ one from female  A cell w/ both sets of homologous chromosomes is ______,meaning 2 sets(2N)---For Drosophilia,2N=8-2 complete sets of chromosomes and 2 complete sets of genes.  Gametes,however contain a ______#-1 set of chromosomes- for Drosophilia N=4. B. Meiosis=______ 2 divisions-meiosis I and Meiosis II  Meiosis I –

6 . Chromosomes are replicated 1st . Divide similar to mitosis,except in prophase I each chromosome pairs w/ its corresponding chromosome to make a ______-which has 4 chromatids . They exchange portions of their chromatids in ______- resulting in a exchange of alleles between homologous chromosomes and produces new combinations of alleles. Homomlogous chromosomes separate and 2 new cells are formed Each cell has 4 chromatids,but they are separated  Meiosis II-  No replication previous to M II  Each chromosome has 2 chromatids  4 daughter cells contain haploid # (N)

7 Figure 11-15 Meiosis

Section 11-4

Meiosis I

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Figure 11-17 Meiosis II

Section 11-4 Meiosis II

Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two The chromosomes line up in a The sister chromatids Meiosis II results in four haploid (N) daughter cells, similar way to the metaphase separate and move toward haploid (N) daughter cells. each with half the number of stage of mitosis. opposite ends of the cell. chromosomes as the original.

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8 C. Gamete Formation-In female- 1 egg cell produced and 3 ______. Male produce 4 sperm cells

D. comparing Mitosis and meiosis  Mitosis produces 2 genetically alike diploid cells /also allows for growth  Meiosis produces 4 genetically different haploid cells/for sexual reproduction