Download Ch10notesplus ch11meiosisonly

Chapter 10+Meiosis-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 VOLUMEassuming 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
1
__________________..causing
serious problems for cell.
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 envelopeseparate 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.
o _____________________= disorder in which some
of the body’s cells lose the ability to
regulate growth
5
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 chromosomesfor Drosophilia N=4.
B. 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/
6
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)
Figure 11-15 Meiosis
Section 11-4
Meiosis I
Go to
Section:
7
Figure 11-17 Meiosis II
Section 11-4
Meiosis II
Prophase II
Metaphase II
Anaphase II
Meiosis I results in two
The chromosomes line up in a The sister chromatids
haploid (N) daughter cells,
similar way to the metaphase separate and move toward
each with half the number of stage of mitosis.
opposite ends of the cell.
chromosomes as the original.
Telophase II
Meiosis II results in four
haploid (N) daughter cells.
Go to
Section:
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
8