Chapter 10-Cell Growth & Division

Chapter 10-Cell Growth & Division

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

  1. Cell Growth
  2. Limits to Cell Growth
  3. 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. 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.

  1. Cell Division

***simpler in prokaryotes

  1. 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

  1. Cell Cycle

➪______isin- between phase

➪______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

  1. Mitosis-4 phases

***Label ANAPHASE above ______

  1. Prophase

➪Longest phase

➪Chromosomes become visible

➪______,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

  1. Metaphase-
  2. chromosomes line up @ center
  3. Centromeres go to 2 poles
  1. Anaphase-
  2. Centromeres split
  3. 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

  1. Cytokinesis-divison of cytoplasm
  • Usually along w/ Telophase
  • Cell plate forms in plants that becomes the ______

III.

  • ______= disorder in which some of the body’s cells lose the ability to regulate growth
  • They do not respond to signals that regulate growth
  • Divide uncontrollably,making ______(masses of cells)
  • ______=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.

  1. 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.

  1. Meiosis=______

2 divisions-meiosis I and Meiosis II

Meiosis I –

  • 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)

  1. Gamete Formation-In female- 1 egg cell produced and 3 ______.

Male produce 4 sperm cells

  1. 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

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