Transcript
• Identify and describe the main phases of the cell cycle
• Identify what form DNA is in during dif ferent stages of the cell cycle
• Describe 3 key events during interphase
• Identify and describe 4 main phases of mitosis
• Compare cytokinesis in plant and animals cells
5A: CELL CYCLE &
5B: MITOSIS
The life of a cell is described as the cell cycle.
Divided into three stages:
INTERPHASE: Cells carry out normal functions
MITOSIS: Duplication of genetic material and division of the nucleus
CYTOKINESIS: Cell with 2 nuclei splits to form two identical daughter cells.
THE CELL CYCLE
Longest stage in the cell cycle
During this phase DNA is in the form of chromatin
Divided into three parts
1. Growth and Preparation: Cell increases in size while performing its
usual functions
1. DNA Replication: DNA replicates making an exact copy of itself
1. Continued Growth and Preparation: Cell continues to grow and
makes copies of its organelles
INTERPHASE
INTERPHASE – DNA REPLICATION
Shortest stage in the cell cycle
Contents of the nucleus divide resulting in two daughter
nuclei that are identical to the original parent cell
MITOSIS
Important structures:
Spindle Fibers: Protein structures that move chromosomes during
mitosis
Centrioles (Animal cells only): Organelles that control the spindle
fibers. *add label to animal cell diagram
MITOSIS
Mitosis is divided into 4 stages (PMAT)
1. Prophase (early prophase & late prophase)
2. Metaphase
3. Anaphase
4. Telophase
MITOSIS
Early Prophase
Duplicated chromosomes
condense into X-shape
Nucleolus disappears
Spindle fibers start to form
and spread across the cell
Centrioles move to opposite
ends of the cell
Late Prophase
Spindle fibers complete
forming
Spindle fibers attach to
chromosomes at the
centromere
Nuclear membrane
disappears
MITOSIS - PROPHASE
Spindle fibers pull chromosomes into a line across the
metaphase plate at the center of the cell
MITOSIS - METAPHASE
Spindle fibers contract and shorten to separate sister
chromatids and pull to opposite ends of the cell
Once separated, sister chromatids are now considered
daughter chromosomes
MITOSIS - ANAPHASE
Final stage of mitosis
A complete set of chromosomes is at each end of the cell
Nuclear membranes form around each set of chromosomes
Nucleolus reappears
Spindle fibers disappear
There are two nuclei in one cell
MITOSIS - TELOPHASE
Final stage of the cell cycle
Cell with two nuclei splits into two daughter cells
New cells are identical to each other and to the parent cell
Cytokinesis is dif ferent in plant and animal cells due to the
presence of a cell wall in plants.
Animal cell: Cell membrane pinches together to separate two halves
Plant cell: Cell plate forms along center of the cell
CYTOKINESIS
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