1. CELL GROWTH & DIVISION 8-2
Image from:
CELL GROWTH
& DIVISION
8-2
Image by Riedell

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

3. 2 Reasons why cells divide
2. _____________________ As cell grows bigger demand for transport across membrane is too great

4. Need for these depends on ___________
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

5. 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

6. BIGGER CELLS NEED MORE FOOD and OXYGEN, but CAN’T TRANSPORT
IT FAST ENOUGH or IN BIG
ENOUGH QUANTITIES!

7. mainly by increasing cell number
Image from:
Image by Riedell
Multicellular organisms grow
mainly by increasing cell number

8. DNA CAN BE: SPREAD OUT IN NON-DIVIDING CELLS SCRUNCHED UP
IN DIVIDING CELLS

9. DNA in PROKARYOTES BACTERIAL DNA is CIRCULAR HAVE ONE CHROMOSOME
NO NUCLEUS; ATTACHED TO CELL MEMBRANE

10. DNA in EUKARYOTES (Plants & Animals)
DNA is ROD-SHAPED CHROMOSOMES
MANY PAIRS
FOUND IN NUCLEUS

11. Chromosome structure ___________________ 2 identical arms
constricted area holds chromatids together
__________________ PAIR
2 of each chromosome (one from mom; one from dad)

12. HOMOLOGOUS CHROMOSOMES
SAME SIZE
SAME SHAPE
CARRY GENES for the SAME TRAITS
BUT ______________!
(Don’t have to have the SAME CHOICES)

13. CELL DIVISION in PROKARYOTES
Bacteria reproduce using
__________________________________

14. ______________ = series of events that cells go through as they grow and develop
cells alive cell cycle

15. 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

16. CELL DIVISION MITOSIS – Nuclear division Prophase Metaphase Anaphase
Telophase
Cytokinesis – Cytoplasm divides
G0 – cell stops dividing (Ex: nerve cell)

19. INTERPHASE (G1 - S - G2) Can’t see chromosomes
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

20. PROPHASE 1st dividing phase DNA scrunches into chromosomes
Pearson Education Inc publishing as Pearson Prentice Hall
PROPHASE
1st dividing phase
DNA scrunches into chromosomes
Centrioles appear in centrosome region & move to poles
Nuclear membrane & nucleolus disappear
Spindle fibers form & attach to chromosomes

21. ___________ region organizes spindle
CENTROSOME
Spindle MICROTUBULES are part of cytoskeleton

22. METAPHASE Chromosomes line up in ___________
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23. ANAPHASE Centromeres split Centrioles pull chromatids_______
Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

24. 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

25. CYTOKINESIS Cytoplasm splits into 2 cells
ANIMAL CELLS pinch cytoplasm in two
with a ______________________

26. 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.

27. Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

28. Videos
Click a hyperlink to choose a video.
Animal Cell Mitosis Animal Cell Cytokinesis

29. Concept Map Cell Cycle Section 10-2 includes is divided into