Transcript Cell cycle - Schoolwires

Mrs. Gilbert
 Identify
the phases of the cell cycle
 Discuss the activities of each phase of mitosis
 Compare the genetic makeup of cells before
and after mitosis
 Compare reproduction in eukaryotic and
prokaryotic cells
 Cell
cycle
 Centromere
 Cleavage furrow
 Cytokinesis
 Deoxyribonucleic acid (DNA)
 Interphase
 Metaphase
 Mitosis
 Sister chromatid
 Spindle fibers
 Defined-
a course or series of events or
operations that repeats
 One pattern seen in different parts of life
 Saying life runs in cycles means that many of
life’s activities repeat themselves.
 It also means that many actions start at one
point.
 These actions go through different steps to
return to that same point.
 Upon returning to that point, they then begin
the cycle all over again.
All
cells are produced from
other cells.
But
how?
3
Stages:
(1)
Interphase
(3)
Cytokinesis
(2)
Mitosis
 During
interphase:

the cell grows

makes a copy of its DNA
(DNA Replication)
 Deoxyribonucleic

The code that controls all of the cell’s activities
 DNA


Acid
Structure = “double helix”
Handrails (outside)= structural
support
Bases (inside) = genetic code
 DNA
is stored in the
nucleus as
chromosomes
 DNA
Replication:

DNA unzips and the 2
sides separate

New bases attach to the
2 old strands, creating 2
identical copies of the
original DNA
A
cell spends most of its
life in interphase


Nuclear membrane &
nucleolus are clearly visible
Chromosomes are NOT
visible
 During
mitosis:

the cell’s
nucleus
divides into 2

since 2 copies of DNA were made during
interphase, each nucleus gets 1 complete copy

Steps of Mitosis
1.
Prophase


Chromosomes
become visible
Nucleolus & nuclear
membrane break down
& disappear

Steps of Mitosis
1.
Prophase


Centrioles move to
opposite ends of the cell
(poles)
Spindle fibers appear

Steps of Mitosis
2.
Metaphase


Chromosomes line up
Centromeres attach to
spindle fibers

Steps of Mitosis
3.
Anaphase


Centromeres split
2 strands of chromosomes
separate & move to
opposite ends of the cell

Steps of Mitosis
4.
Telophase


Centrioles & spindle
fibers disappear
Chromosomes
become harder to
see

Steps of Mitosis
4.
Telophase

Nuclear membrane
& nucleolus reform
Plant Cell Mitosis Animal Cell Mitosis
 During

cytokinesis:
The cell’s cytoplasm divides
to create 2 new, identical
cells
2 copies of
DNA are
made
(1)
Interphase
(2)
Mitosis
nucleus
divides in 2
cytoplasm
divides to create
2 identical cells
(3)
Cytokinesis
 Some
organisms reproduce by mitosis
 Asexual


reproduction:
A new organism is
produced from a single
parent
offspring are genetically
identical to the parent
3



types:
binary fission
budding
regeneration
 Budding—a
new organism grows from the
body of the parent organism

Example: hydra
 Regeneration—a
new organism can develop
from a piece of the old organism

Example: starfish
 www.sciencespot.net
 Biology:
Cycles of life. Circle Pines: MN. AGS
Publishing. (pp.3, 246-250)