Lecture AP Biology Chapter 12 The cell cycle

Ch.12 Warm up
1.

Define: genome, gametes, chromatin, chromosome,
centromere, kinetochore, checkpoint, Cdk, MPF

2.

What is the longest part of the cell cycle? Why?

1.

If the diploid number is 46, the haploid number is?


Ch. 12 Warm up
1.

At the end of mitosis and cytokinesis, how do
daughter cells compare with their parent cell when
it was in G1?

2.

A cell’s DNA was measured at 5 picograms. DNA
levels range from 3-6 pgms in the cell cycle . What
stage of the cell cycle is this cell in. How do you
know?

3.

At metaphase, if the haploid number is 3, how many
chromatids does this cell have?


Ch. 12 Warm up
What is the correct phase of the cell cycle/mitosis for
the following:
A.Most cells that no longer divide or rarely divide are in
this phase
B.Sister chromatids separate and move apart
C.Mitotic spindle begins to form
D.Cell plate or cleavage furrow form
E.Chromosomes replicate
F.Chromosomes line up on equatorial plate
G.Nuclear membrane forms
H.Chromosomes become visible


Ch. 12 Warm up
1.
2.

3.

Describe the difference between plant and animal
cell division.
Measurements of the DNA amount per nucleus
were taken. DNA levels ranged from 3-6
picograms per nucleus, what stage of the cell cycle
are these cells in?

a) One nucleus has 3 pgrms
b) One with 6 pgrms
c) 5 pgrms
Describe binary fission.


Ch. 12 Warm up
1.

How do we know the cell uses chemical signals?

2.

Summarize the cell control system.

3.

Compare a cancer cell to a normal cell. What goes
wrong?


Ch. 13 Warm up
1.

Compare sexual to asexual reproduction.

2.

Compare/contrast mitosis to meiosis.

3.

Describe the events of meiosis.


Ch. 13 Warm up
1.

Describe and compare the 3 sexual life cycles

1.

How does random assortment, crossing over and
random fertilization contribute to genetic variation?

2.

Define: locus, karyotype, alternation of
generations, synapsis, tetrad, chiasmata


Chapter 12: The Cell Cycle


What you must know:
The structure of the duplicated chromosome.
 The cell cycle and stages of mitosis.
 The role of kinases and cyclin in the regulation
of the cell cycle.


Cell Cycle: life of a cell from its formation until it
divides
Functions of Cell Division:
Division
Reproduction, Growth and
Tissue Repair


Genome = all of a cell’s genetic info (DNA)



Prokaryote:
Prokaryote single, circular chromosome
Eukaryote:
Eukaryote more than one linear chromosomes
 Eg. Human:46 chromosomes, mouse: 40, fruit fly:
8


Each chromosome must be duplicated before cell
division


Duplicated chromosome = 2 sister chromatids
attached by a centromere

Somatic Cells

Gametes




Body cells
Diploid (2n): 2 of each
type of chromosome
Divide by mitosis



Sex cells (sperm/egg)
Haploid (n): 1 of each
type of chromosome
Divide by meiosis



Humans: 2n = 46



Humans: n = 23







Phases of the Cell Cycle


Phases of the Cell Cycle


The mitotic phase alternates with interphase:
G1  S  G2  mitosis  cytokinesis

Interphase (90% of cell cycle)
G1 Phase: cell grows and carries out normal functions


S

Phase: duplicates chromosomes
G2 Phase: prepares for cell division
M Phase (mitotic)
Mitosis: nucleus divides
Cytokinesis: cytoplasm divides



Mitosis: Prophase  Metaphase  Anaphase 
Telophase

Mitosis


Continuous process with observable structural
features:
 Chromosomes become visible (prophase)
 Alignment at the equator (metaphase)
 Separation of sister chromatids (anaphase)
 Form two daughter cells (telophase & cytokinesis)


Prophase & Prometaphase


Metaphase & Anaphase


Cytokinesis
 Cytoplasm of cell divided
 Animal Cells : cleavage furrow
 Plant Cells : cell plate forms


Cytokinesis in animal vs. plant cells


Animal Cell Division


Plant Cell Division

Which phases of the cell cycle can you identify?


Bacterial cells divide by Binary Fission