The Cell Cycle Mitosis
Apr 01, 2015
The Cell Cycle
Mitosis
The Cell Cycle
The regular sequence of growth and division that cells undergo.
The Cell Cycle
6 Parts Interphase Prophase* Metaphase Anaphase Telophase Cytokinesis
• *When mitosis begins.
Stage 1: Interphase
During interphase the cell grows, makes a copy of its DNA, and prepares to divide into 2 cells. Cell grows - The cell grows to full size and
produces structures it needs. Copies DNA -Cell makes a full copy of the
DNA. This process is known as replication.• DNA is found in the chromatin.
Stage 1: Interphase
Preparing for Division - After replication has occurred, the cell copies its centrioles.
• Centrioles - Cylindrical structures that produce microtubules used in mitosis.
Stage 2: Mitosis
Mitosis - The stage during which the cell’s nucleus divides into two new nuclei.
During mitosis, one copy of the DNA is distributed into each of the two daughter cells. Daughter cells - The cells that are produced following
cell division.
Stage 2: Mitosis Part 1
Prophase - Chromatin condenses in the nucleus to form chromosomes.
• Chromosomes are made of chromatin. The two chromatids that make up a chromosome is held together in the center by a centromere. (make a diagram.)
The centrioles move to opposite sides of the nucleus. The nuclear envelope breaks down.
Stage 2: Mitosis
Part2
Metaphase -• Chromosomes line up across the center of the
cell.• Each chromosome attaches to a spindle fiber at
its centromere.• The spindle fibers are connected to the centrioles.
Stage 2: Mitosis Part 3
Anaphase - • The centromeres split, and the chromatids
separate.• Each chromatid becomes a new chromosome.• New chromosomes move to opposite ends of the
cell.• Cell begins to stretch out as the opposite ends are
pushed apart.
Stage 2: Mitosis
Part 4 Telophase -
• Chromosomes lose their rod-like appearance• New nuclear envelope forms around the bundle of
chromosomes.• Two halves separate even farther.
Stage 3: Cytokinesis
Cytokinesis is the division of cytoplasm and organelles into each of the 2 new cells.
Stage 3: Cytokinesis
During cytokinesis: Cell membrane pinches in around the middle of the
cell. Cell splits in two and divides the cytoplasm. Each daughter cell has an identical set of
chromosomes and about 1/2 the organelles. Cytokinesis leads back into interphase.
Stage 3: Cytokinesis
Cytokinesis in PLANTS is different. A cell plate forms across the middle of the
cell, which gradually develops into the new cell membranes.
The new cell walls form around the cell membranes.
DNA Structure
Double helix - Twisted ladder shape The sides of the ladder are made up of sugar
molecules called deoxyribose, and alternate with a phosphate molecule.
The rungs are made up of a pair of nitrogen bases. 4 nitrogen bases: adenine (A), thymine (T), guanine
(G), and cytosine (C).
DNA Replication Process
The DNA “ladder” unwinds and unzips, leaving 1 of the 2 nitrogen bases on either side of the “ladder”.
Bases that are floating in the nucleus pair up with its appropriate partner. Adenine pairs with Thymine Guanine pairs with Cytosine