CELL GROWTH & DIVISION10-1 & 10-2
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
DNA OVERLOAD
2 Reasons why cells divide
2. _____________________As cell grows bigger demand for transport across membrane is too great
Material exchange can’t keep up
Ability to transport of oxygen, food, waste across cell membrane depends on _______________
Need for these depends on ___________
SURFACE AREA
CELL VOLUME
As cell grows these DON’T increase at the same rate
See relationshipbetween volume and SA
Go to Section:
Cell Size
Surface Area (length x width x 6)Volume (length x width x height)
Ratio of Surface Area to Volume
Ratio of Surface Area to Volume in Cells
Section 10-1
BIGGER CELLS NEED MORE FOODand OXYGEN, but CAN’T
TRANSPORTIT FAST ENOUGH or IN BIGENOUGH QUANTITIES!
Multicellular organisms grow mainly by increasing cell number
SPREAD OUT INNON-DIVIDING CELLS
SCRUNCHED UPIN DIVIDINGCELLS
CHROMATIN CHROMOSOMES
DNA CAN BE:
DNA in PROKARYOTES
• BACTERIAL DNA is CIRCULAR• HAVE ONE CHROMOSOME• NO NUCLEUS;
ATTACHED TO CELL MEMBRANE
DNA in EUKARYOTES(Plants & Animals)
• DNA is ROD-SHAPED CHROMOSOMES• MANY PAIRS• FOUND IN NUCLEUS
Chromosome structure
• ___________________ 2 identical arms
• __________________ constricted area
holds chromatids together
•__________________ PAIR 2 of each chromosome(one from mom; one from dad)
CHROMATIDS
CENTROMERE
HOMOLOGOUS
HOMOLOGOUS CHROMOSOMES
• SAME SIZE• SAME SHAPE• CARRY GENES for the
SAME TRAITS• BUT ______________! (Don’t have to have
the SAME CHOICES)
NOT IDENTICAL
CELL DIVISION in PROKARYOTES
Bacteria reproduce using__________________________________ BINARY FISSION
______________ =series of events that cells go through as they grow and develop
cells alive cell cycle
CELL CYCLE
CELL CYCLEINTERPHASE – 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 DIVISIONMITOSIS – Nuclear division Prophase Metaphase
AnaphaseTelophaseCytokinesis – Cytoplasm divides
G0 – cell stops dividing (Ex: nerve cell)
Go to Section:
M phase
G2 phase
S phase
G1 phase
Figure 10–4 The Cell Cycle
Section 10-2
INTERPHASE (G1 - S - G2)
In between divisionsCells are in this phase most of the timeCan see nucleus DNA spread out as chromatin
Can’t see chromosomes DNA gets copied (S)
Cell gets ready to divide
PROPHASE1st dividing phase
Spindle fibers form & attach to chromosomes
Nuclear membrane & nucleolus disappear
DNA scrunches into chromosomes
Centrioles appear in centrosome region & move to poles
________ region organizes spindle
Spindle MICROTUBULES are part of cytoskeleton
CENTROSOME
METAPHASE
Chromosomes line up in ___________middle
ANAPHASECentromeres splitCentrioles pull chromatids_______apart
TELOPHASE (reverse prophase steps)
See ______ nuclei
Nuclear membrane & nucleolus returnChromosomes spread out as chromatinCentrioles disappear
Spindle fibers disappear
two
CYTOKINESISCytoplasm splits into 2 cells
ANIMAL CELLS pinch cytoplasm in two with a ______________________CLEAVAGE FURROW
CYTOKINESISCytoplasm splits into 2 cellsPLANT CELLS can’t pinch because they have a sturdy ____________
Plant cells separate cytoplasm by growing a _______________ down the middle.
CELL PLATE
CELL WALL
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Videos
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Animal Cell Mitosis Animal Cell Cytokinesis
Go to Section:
includes
is divided into is divided into
Concept Map
Section 10-2
Cell Cycle
Go to Section:
includes
is divided into is divided into
Concept Map
Section 10-2
Cell Cycle
M phase (Mitosis)
Interphase
G1 phase S phase ProphaseG2 phase Metaphase TelophaseAnaphase