Notes about Chromosomes and the cell cycle

1. Learning Objective: I can describe how cells divide and
the different phases of the cell cycle.

2. What is the process cells undergo before they
become specialized?

3.  Until the late 1600s, scientists used to think new cells came from Spontaneous
Generation (nonliving things giving rise to living things)

4.  Francesco Redi discovered that maggots came from flies, not from decaying meat

5.  Microorganisms were discovered- which reopened debate about where living things
come from

6.  Louis Pasteur proved that microorganisms came from other microorganisms

8.  All life comes from other life
 Thanks Pasteur.

9.  Chromosomes- rod-shaped structures composed of DNA and proteins
 DNA- the genetic code for organisms
 Chromatin- a loosely coiled DNA strand
 Chromatid- a single strand of coiled DNA (replicated, condensed
chromosome)
 Centromere- holds the two chromatids together

12. What are chromosomes?
A. rod-shaped structures composed of DNA and proteins
B. the genetic code for organisms
C. a loosely coiled DNA strand
D. a single strand of coiled DNA

13. What are chromosomes?
A. rod-shaped structures composed of DNA and proteins
B. the genetic code for organisms
C. a loosely coiled DNA strand
D. a single strand of coiled DNA

14. A. rod-shaped structures composed of DNA and proteins
B. the genetic code for organisms
C. Structure that holds the two chromatids together
D. a loosely coiled DNA strand

15. A. rod-shaped structures composed of DNA and proteins
B. the genetic code for organisms
C. Structure that holds the two chromatids together
D. a loosely coiled DNA strand

16. A. A structure that holds two chromatids together?
B. a single strand of coiled DNA (replicated, condensed chromosome)
C. a loosely coiled DNA strand
D. the genetic code for organisms

17. A. A structure that holds two chromatids together
B. a single strand of coiled DNA (replicated, condensed chromosome)
C. a loosely coiled DNA strand
D. the genetic code for organisms

18. A. A structure that holds the two chromatids together
B. a single strand of coiled DNA (replicated, condensed chromosome)
C. a loosely coiled DNA strand
D. rod-shaped structures composed of DNA and proteins

19. A. A structure that holds the two chromatids together
B. a single strand of coiled DNA (replicated, condensed chromosome)
C. a loosely coiled DNA strand
D. rod-shaped structures composed of DNA and proteins

20. A. DNA
B. A Chromosome
C. A Centromere
D. A Chromatin

21. A. DNA
B. A Chromosome
C. A Centromere
D. A Chromatin

22. A. DNA
B. A centromere
C. A chromatid
D. A chromosome

23. A. DNA
B. A centromere
C. A chromatid
D. A chromosome

24. A. A chromosome
B. A centromere
C. A chromatid
D. DNA

25. A. A chromosome
B. A centromere
C. A chromatid
D. DNA

26. Let’s move on to the cell cycle

27.  Interphase
 G1 Phase
 S Phase (Synthesis)
 G2 Phase
 Mitosis
 Prophase
 Metaphase
 Anaphase
 Telophase
 Cytokinesis
G1 Phase
S Phase
G2 Phase
Mitosis
Pro
Meta
Ana
Telo
Cytokinesis
Draw this!

28. https://www.youtube.com/watch?v=ZeW8HaCUtOQ

29.  Stem cells divide to become specialized cells

30.  Most cells!
 Specialized cells like neurons, cardiac cells, and muscle cells have already divided
and won’t ever divide again

31. 1. Interphase- starts right after cell division; longest phase of a cell’s “life”
a. G1 Phase- Cell grows
b. S Phase- DNA is copied into sister chromatins
c. G2 Phase- Cell grows and prepares for cell division (mitosis)
G1 Phase
S Phase
G2 Phase

32.  The division of the nucleus (PMAT)
 Prophase
 Metaphase
 Anaphase
 Telophase

33. 1. Nucleoli disintegrates
2. Chromatin condenses into chromatids and chromosomes
3. Centrioles migrate to ends of the cell
4. Spindle fibers form from centrioles
Centrioles
Spindle fibers
Nucleoli
(disappearing)
Chromosomes
Draw these!

34.  Chromosomes move to
the center of cell
Centrioles and
spindle fibers

35.  Chromatids separate into individual
chromosomes
 Migrations towards poles (sides of
cell) begins

36.  Nuclear membrane reforms
 Chromatin lengthen

37.  The division of the cell into daughter
cells
 Plasma membrane pinches together in
animal cells
 Cell plate appears in plant cells

38.  Cleavage furrow forms
 Membrane splits in two

39.  Cell plate forms
 Membrane splits
 Cell plate becomes cell
wall

40.  Stem cells divide to become specialized cells

41.  Most cells!
 Specialized cells like neurons, cardiac cells, and muscle cells have already divided
and won’t ever divide again

42.  The Goal: Create more identical
cells
 In humans, a cell with 46
chromosomes will divide into two
daughter cells, both with 46
chromosomes
G1 Phase
S Phase
G2 Phase
Mitosis
Pro
Meta
Ana
Telo
Cytokinesis