2. CELL GROWTH
& DIVISION
Image by Riedell

3. 2 Reasons why cells divide
DNA OVERLOAD
1. _____________________ As cells grow 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

4. 2 Reasons why cells divide
Material exchange can’t keep up
2. _____________________ As cell grows bigger demand for transport across membrane is too great

5. Ability to transport of oxygen, food, waste across cell membrane depends on _______________
SURFACE AREA

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
CHROMATIN
CHROMOSOMES

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 CHROMATIDS CENTROMERE HOMOLOGOUS
Sister_________________ identical arms
__________________
constricted area holds chromatids together
CENTROMERE
HOMOLOGOUS
__________________ 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)
NOT IDENTICAL

13. Vocabulary to Know:
Karotypes- “chromosomes map” used to ID potential problems.

14. Vocabulary to Know:
Somatic cell- any cell in the body except egg and sperm
Diploid- contain two sets of chromosomes
Human diploid number- 46 total chromosomes which is equal to 23 pairs of chromosomes
Haploid- egg and sperm, half the genetic information
Spindle- collection of fibers made of microtubules involved in cell division (aid in stretching the cell apart)

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

16. Cell Cycle Concept Map Cell Cycle includes is divided into

17. Cell Cycle Concept Map Cell Cycle includes M phase (Mitosis)
Interphase
is divided into
is divided into
G1 phase
S phase
Prophase
G2 phase
Metaphase
Telophase
Anaphase

19. ÷ Cells STOP dividing Ex: nerve cell Copy DNA
NOT dividing
G1 S G2
Copy DNA
Growth Cell makes molecules & organelles needed by new cell DNA = chromatin
Growth Cell is “doing its job” DNA=chromatin Cells spend most of life here ÷
Dividing
(DNA=chromosomes)

20. Can’t see chromosomes DNA is spread out as chromatin
INTERPHASE (IN BETWEEN DIVIDING)
DNA is spread out as chromatin
Nuclear membrane is visible
Nucleolus is visible
DNA is copied during S phase
Can’t see chromosomes
DNA gets copied (S)
Cell gets ready to divide

21. PROPHASE Chromatin scrunches into chromosomes
Pearson Education Inc publishing as Pearson Prentice Hall
PROPHASE
1st dividing phase
Chromatin scrunches into chromosomes
Centrioles appear & move to poles
Nuclear membrane & nucleolus disappear
Spindle fibers appear

22. METAPHASE (MIDDLE) Chromosomes line up in ___________ middle
Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

23. ANAPHASE (APART) Centromeres split and pull chromatids to the poles
Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

24. Nuclear membrane & nucleolus return
TELOPHASE (TWO NUCLEI)
“REVERSE PROPHASE”
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)
Cytoplasm splits into 2 cells
Cleavage furrow pinches in animal cells
CLEAVAGE FURROW

26. CYTOKINESIS Cell Plate forms in plant cells CELL PLATE