1. Image from: http://www. bcps. org/offices/lis/models/life/images/grow
CELL GROWTH
& DIVISION
Image by Riedell

2. 2 Reasons why cells divide
DNA OVERLOAD
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
Material exchange can’t keep up
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 ___________
SURFACE AREA
CELL VOLUME
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
Multicellular organisms grow
mainly by increasing cell number

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

9. Chromosomes
Chromosome animation

10. DNA in PROKARYOTES BACTERIAL DNA is CIRCULAR HAVE ONE CHROMOSOME
NO NUCLEUS; DNA is found in the nucleoid region

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

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

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

14. CELL DIVISION in PROKARYOTES
Bacteria reproduce using
__________________________________
BINARY FISSION

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

16. CELL CYCLE INTERPHASE – non-dividing phase
G1- Grow bigger DNA is spread out as chromatin
S - Synthesis (copy DNA) & chromosomal proteins
G2- Grow bigger, make organelles & molecules needed for cell division

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

18. Figure 10–4 The Cell Cycle Section 10-2 G1 phase M phase S phase

20. INTERPHASE (G1 - S - G2) Can’t see chromosomes
In between divisions Cells are in this phase most of the time
Can see nucleus and nucleoli
DNA spread out as chromatin
Microtubules outside nucleus, centrioles
Have doubled, organelles replicated
Can’t see chromosomes
DNA gets copied (S)
Cell gets ready to divide

21. 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

22. Prometaphase
Microtubules emerge from the centrioles at the poles=spindle fibers
Kinetochore fibers extend from centromere to centriole throwing chromosomes into agitated motion
Asters form around centrioles

23. ________ region organizes spindle
CENTROSOME
Spindle MICROTUBULES are part of cytoskeleton

24. METAPHASE middle Chromosomes line up in
___________ and attach to spindle fibers
middle
Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

25. ANAPHASE Centromeres split Centrioles pull chromatids_______ apart
Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

26. Anaphase
Kinetochores (found within chromosomes) are powered by ATP and “walk” the daughter chromosomes to opposite poles.

27. two TELOPHASE (reverse prophase steps) See ______ nuclei
Nuclear membrane & nucleolus return
Chromosomes spread out as chromatin
Centrioles disappear
Spindle fibers disappear and go back to
microtubles
Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

28. CYTOKINESIS Cytoplasm splits into 2 cells CLEAVAGE FURROW
ANIMAL CELLS pinch cytoplasm in two
with a ______________________ (use of microfilaments)
CLEAVAGE FURROW

29. 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.
CELL WALL
CELL PLATE

30. 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

31. 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

32. 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

33. 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

34. 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

35. 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

36. Videos
Animal Cell Mitosis
Animal Cell Cytokinesis

37. Concept Map Cell Cycle Section 10-2 includes M phase (Mitosis)
Interphase
is divided into
is divided into
G1 phase
S phase
Prophase
G2 phase
Metaphase
Telophase
Anaphase