Transcript CHROMOSOMES - Bishop Montgomery High School

Image from: http://www.bcps.org/offices/lis/models/life/images/grow.JPG
CELL GROWTH
& DIVISION
10-1 & 10-2
Image by Riedell
2 Reasons why cells divide
1. _____________________
As cell grows bigger demand on DNA
“genetic library” becomes too great
Ex: Small town library has 1000 books.
As town grows and more people
borrow books, there may be a
waiting list to read the
most popular titles
http://www.adc.state.az.us/images/Off-Library.JPG
2 Reasons why cells divide
2. _____________________
As cell grows bigger demand for
transport across membrane is too
great
http://www.animationlibrary.com
Ability to transport of oxygen,
food, waste across cell membrane
depends on _______________
Need for these depends on
___________
As cell grows these DON’T increase at the
same rate
Ratio of Surface Area to Volume in Cells
Section 10-1
Cell Size
Surface Area
(length x width x 6)
Volume
(length x width x height)
Ratio of Surface Area
to Volume
Go to
Section:
BIGGER CELLS NEED MORE FOOD
and OXYGEN, but CAN’T TRANSPORT
IT FAST ENOUGH or IN BIG
ENOUGH QUANTITIES!
http://www.animationlibrary.com
Image from: http://www.bcps.org/offices/lis/models/life/images/grow.JPG
Image by Riedell
Multicellular organisms grow
mainly by increasing cell number
DNA CAN BE:
SPREAD OUT IN
NON-DIVIDING
CELLS
SCRUNCHED UP
IN DIVIDING
CELLS
DNA in PROKARYOTES
• BACTERIAL DNA is CIRCULAR
• HAVE ONE CHROMOSOME
• NO NUCLEUS;
ATTACHED TO CELL MEMBRANE
http://www.origin-life.gr.jp/3202/3202121/fig6.jpg
DNA in EUKARYOTES
(Plants & Animals)
• DNA is ROD-SHAPED CHROMOSOMES
• MANY PAIRS
• FOUND IN NUCLEUS
http://cellbio.utmb.edu/cellbio/chrom2.jpg
Chromosome structure
• ___________________
2 identical arms
• __________________
constricted area
holds
chromatids together
•__________________ PAIR
2 of each chromosome
(one from mom; one from dad)
HOMOLOGOUS CHROMOSOMES
• SAME SIZE
• SAME SHAPE
• CARRY GENES for the
SAME TRAITS
• BUT ______________!
(Don’t have to have the
SAME CHOICES)
http://arnica.csustan.edu/biol3020/cell_division/cell_division.htm
http://sps.k12.ar.us/massengale/genetics%20tutorial.htm
CELL DIVISION in PROKARYOTES
Bacteria reproduce using
__________________________________
http://fig.cox.miami.edu/~cmallery/150/mitosis/fission.jpg
______________ =
series of events that cells go
through as they grow and
develop
cells alive cell cycle
CELL CYCLE
INTERPHASE – non-dividing phase
G1- Grow bigger
Cell is “doing its job”
DNA is spread out as chromatin
S - Synthesis (copy DNA)
& chromosomal proteins
G2- Grow bigger, make organelles &
molecules needed for cell division
CELL DIVISION
MITOSIS – Nuclear division
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis – Cytoplasm divides
G0 – cell stops dividing
(Ex: nerve cell)
INTERPHASE (G1 - S - G2)
In between divisions
Cells are in this phase most of the time
Can see nucleus
DNA spread out as chromatin
Can’t see chromosomes
DNA gets copied (S)
Cell gets ready to divide
Pearson Education Inc publishing as Pearson Prentice Hall
PROPHASE
1st dividing phase
http://www.life.uiuc.edu/plantbio/102/lectures/08mit&veg102.html
DNA scrunches into chromosomes
Centrioles appear in centrosome region
& move to poles
Nuclear membrane & nucleolus disappear
Spindle fibers form & attach to
chromosomes
CENTROSOME region organizes spindle
___________
Spindle MICROTUBULES are part of cytoskeleton
http://www.coleharbourhigh.ednet.ns.ca/library/organelle_worksheet.htm
METAPHASE
Chromosomes line up in
___________
Images from:
Pearson Eduction Ince; Publishing as Pearson Prentice Hall
http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0247.JPG
ANAPHASE
Centromeres split
Centrioles pull chromatids_______
Images from:
Pearson Eduction Ince; Publishing as Pearson Prentice Hall
http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0247.JPG
TELOPHASE (reverse prophase steps)
See ______ nuclei
Nuclear membrane & nucleolus return
Chromosomes spread out as chromatin
Centrioles disappear
Spindle fibers disappear
Images from:
Pearson Eduction Ince; Publishing as Pearson Prentice Hall
http://www2.bc.cc.ca.us/cnewton/Biology%2011/Mitosis.html
CYTOKINESIS
Cytoplasm splits into 2 cells
ANIMAL CELLS pinch cytoplasm in two
with a ______________________
CYTOKINESIS
Cytoplasm splits into 2 cells
PLANT CELLS can’t pinch because
they have a sturdy ____________
Plant cells separate cytoplasm by
growing a _______________
down the middle.
http://www.eastcentral.edu/acad/depts/BI/plant_mitosis_nolabels.html
Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Concept Map
Section 10-2
Cell Cycle
includes
is divided into
Go to
Section:
is divided into