1. THE CELLULAR BASIS OF INHERITANCE
CHAPTER 9

2. Why Is Cell Reproduction Essential for Life?
#1) Maintain/Heal the Body
– TO REPLACE LOST OR DAMAGED
CELLS
Example:
Every minute of the day we lose about 30,000 to 40,000 dead skin cells off the surface of our skin.

3. Why Is Cell Reproduction Essential for Life?
#2) GROWTH
- Increase body size by increasing the number of cells in the body

4. Why Is Cell Reproduction Essential for Life?
#3) REPRODUCTION = TO CREATE
A COMPLETE NEW ORGANISM.
2 TYPES OF REPRODUCTION:
a) ASEXUAL
b) SEXUAL

5. ASEXUAL REPRODUCTION How Many Parents? SINGLE PARENT
OFFSPRING ARE GENETICALLY IDENTICAL TO EACH OTHER AND TO PARENT.
SEEN IN UNICELLULAR ORGANISMS AND SOME MULTICELLULAR ORGANISMS SUCH AS PLANTS,FUNGI, AND SOME ANIMALS LIKE SPONGES AND STARFISH.
How Many Parents?

6. SEXUAL REPRODUCTION 2 PARENTS
GENETIC MATERIAL (CARRIED IN EGG AND SPERM) FROM EACH PARENT COMBINES
EACH OFFSPRING IS GENETICALLY DIFFERENT FROM PARENTS
Egg and Sperm are produced through
cell division

7. REVIEW: WHY DO CELLS DIVIDE AND PRODUCE NEW CELLS?
For Maintenance of the body
(multicellular organisms)
For Growth
For Reproduction
(multi- and unicellular organisms)

8. STARTS WHEN A CELL IS “BORN” & ENDS WHEN IT REPRODUCES.
The “CELL CYCLE”
STARTS WHEN A CELL IS “BORN” & ENDS WHEN IT REPRODUCES.
CELL CYCLE PRODUCES CELLS NEEDED FOR GROWTH & MAINTENANCE OF THE BODY

9. The “CELL CYCLE” Cell is not dividing (Most of the time) Cell is
Nucleus
divides
first
Cytoplasm
divides
last

10. The “CELL CYCLE” HAS 2 MAIN STAGES: INTERPHASE MITOTIC PHASE
cell isn’t dividing
MITOTIC PHASE
cell is dividing

11. INTERPHASE
WHAT IS IT?
WHAT HAPPENS DURING IT?

12. INTERPHASE LONGEST STAGE (90% OF THE CELL CYCLE)
THE CELL GROWS & PERFORMS ITS JOB AS A CELL

13. INTERPHASE
IN THIS STAGE DNA EXISTS AS A MASS OF VERY LONG THIN FIBERS CALLED
_________________.
CHROMATIN

14. INTERPHASE
CELL ALSO PREPARES TO REPRODUCE (CELL DIVISION) BY INCREASING ITS NUMBER OF ORGANELLES & BY MAKING COPIES OF ALL ITS _____________.
DNA
muy importante!!!
EACH DNA STRAND IS COPIED & THE 2 COPIES ARE
JOINED AT ONE SPOT CALLED THE __________________.
CENTROMERE

15. DNA IN CHROMATIN FORM

16. What Happens Next?!
After the cell has made all its preparations, then it divides!
On to the Mitotic Phase!!

17. MITOTIC PHASE SHORTEST STAGE of the CELL CYCLE
THIS IS WHERE 1 CELL DIVIDES INTO 2 CELLS
OCCURS IN 2 STEPS:
1) MITOSIS
2) CYTOKINESIS

18. MITOSIS
All about the Nucleus!
In this stage the nucleus divides into 2 and the chromosomes are evenly divided up.
Each daughter nucleus
receives a complete
set of chromosomes

19. MITOSIS CHROMOSOMES CHROMATIDS ____________________. SISTER
ALL THE DUPLICATED CHROMATIN FIBERS NOW COIL UP (GET SHORTER & THICKER) & ARE CALLED
____________________.
EACH CHROMOSOME IS MADE UP OF 2 IDENTICAL HALVES CALLED ______________ .
CHROMOSOMES
SISTER
CHROMATIDS

21. MITOSIS
The SISTER CHROMATIDS SEPARATE & GO TO OPPOSITE ENDS OF THE CELL FORMING 2 NEW “DAUGHTER” NUCLEI

22. CYTOKINESIS
The CYTOPLASM DIVIDES BETWEEN THE 2 NEW “DAUGHTER” NUCLEI FORMING 2 NEW CELLS

23. The “CELL CYCLE” Cell is not dividing (Most of the time) Cell is
MITOTIC
PHASE
INTERPHASE
Nucleus
divides
first
Cytoplasm
divides
last
MITOSIS
CYTO-
KINESIS

24. Name the Structure! ? ? ? ? Chromosomes Centromere ? ? Centromere ?
SISTER
CHROMATIDS ?

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

26. 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

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

29. 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

30. 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

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

32. METAPHASE Chromosomes line up in ___________ middle
Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

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

34. two 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

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

36. 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

37. Interphase Cytokinesis Telophase
Section 10-2
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

38. Interphase Cytokinesis Telophase
Section 10-2
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

39. Interphase Cytokinesis Telophase
Section 10-2
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

40. Interphase Cytokinesis Telophase
Section 10-2
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

41. Interphase Cytokinesis Telophase
Section 10-2
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

42. Interphase Cytokinesis Telophase
Section 10-2
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming