Chapter 9. MITOSIS (CELL DIVISION) AND CELL CYCLE. Activator— kwl chart mitosis. activator. Name the stages of mitosis in order. Impacts, Issues: Henrietta’s Immortal Cells. Cancer cells isolated from Henrietta Lacks established a self-perpetuating lineage of cancer cells
MITOSIS (CELL DIVISION) AND CELL CYCLE
Name the stages of mitosis in order.
Fig. 9-2, p.141
Fig. 9-10, p.149
one chromosome (duplicated)
a One chromosome (unduplicated)
b One chromosome (duplicated)
Fig. 9-3a, p.142
DNA and proteins
arranged as cylindrical fiber
Figure 9.5Page 144
one spindle pole
one of the condensed chromosomes
as a spindle apparatus
one spindle pole
same chromosome (duplicated) in interphase prior to mitosis
mitosis, cytoplasmic division
in daughter cell
in daughter cell
at interphaseMaintaining Chromosome Number
XX (or XY)
Fig. 9-6a, p.145
b The same two
duplicated, in that
cell at interphase,
prior to mitosis
a Two of the chromosomes
in a parent cell at interphase
c Two chromosomes
(unduplicated) in the
parent cell’s daughter
cells, which both start
life in interphase
Fig. 9-6b, p.145
Maintaining Chromosome Number
Duplicated chromosomes begin to condenseand become observable under a microscope; mitotic spindle
a Cell at Interphase
The cell duplicates its DNA, prepares for nuclear division
pair of centrioles
b EARLY PROPHASE
c LATE PROPHASE
d TRANSITION TO METAPASE
Mitosis begins. The DNA and its associated proteins have started to condense. The two chromosomes color-coded purple were inherited from the female parent. The other two (blue) are their counterparts., inherited from the male parent.
Chromosomes continue to condense. New microtubules become assembled. They move one of the two pairs of centrioles to the opposite end of the cell. The nuclear envelope starts to break up.
Now microtubules penentrate the nuclear region. Collectively, they form a bipolar spindle apparatus. Many of the spindle microtubules become attatched to the two sister chromatids of each chromosome.
Fig. 9-7a, p.146
All chromosomes have become lined up at the spindle equator. At this stage of mitosis (and of the cell cycle), they are most tightly condensed
Attachments between the two sister chromatids of each chromosome break. The two are separate chromosomes, which microtubules move to opposite spindle pores.
There are two clusters
of chromosomes, which decondense. Patches of new membrane fuse to form a new nuclear envelope. Mitosis is completed.
Now there are two daughter cells. Each is diploid; its nucleus has two of each type
of chromosome, just like the parent cell.
Fig. 9-7b, p.146
Animal Cell Division—
1 Mitosis is
over, and the spindle is now disassembling.
2 At the former spindle equator, a ring of micro-filaments attached to the plasma membrane contracts.
3As its diameter shrinks, it pulls the cell surface inward.
4Contractions continue; the cell is pinched in two.
Fig. 9-8a, p.148
cell plane forming
1As mitosis ends, vesicles cluster at the spindle equator. They contain materials for anew primary cell wall.
2Vesicle membranes fuse. The wall material is sandwiched between two new membranes that lengthen along the plane of a newly forming cell plate.
3 Cellulose is deposited inside the sandwich. In time, these deposits will form two cell walls. Others will form the middle lamella between the walls and cement them together.
4A cell plate grows at its margins until it fuses with the parent cell plasma membrane. The primary wall of growing plant cells is still thin. New material—cellulose- is deposited on it.
Fig. 9-8b, p.148
Fig. 9-12, p.150
cell at interphase
Fig. 9-15, p.153