Download mitosis - Peoria Public Schools

Big Idea: characteristics from parents are
passed to offspring in predictable ways
Unit 2 Lesson 1 Mitosis
Essential Question: How do cells divide?
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 2 Lesson 1 Mitosis
P92
Splitsville!
Why do cells divide?
• Cell division is important for asexual reproduction, which
involves only one parent organism. – Unicellular
organisms
• Offspring are identical to the parent
• Binary Fission
• Budding
• Most growth in a multicellular organism happens because
cell division produces new cells.
• Cell division also produces cells for repair.
Unit 2 Lesson 1 Mitosis
P93
What happens to genetic material during
cell division?
• The genetic material in cells
is called DNA
(deoxyribonucleic acid).
• In eukaryotic cells, DNA is
found in the nucleus.
• A DNA molecule contains
the information that
determines the traits that a
living thing inherits and
needs to live.
Unit 2 Lesson 1 Mitosis
What happens to genetic
material during cell division?
• During most of a cell’s life cycle, DNA
is found in a mass of loose strands
called chromatin.
• Before cell division, DNA is duplicated.
• As cell division begins, the chromatin
is compacted (condenses) into visible
structures called chromosomes.
• A duplicated chromosome is made of
two identical structures called
chromatids connected by a
centromere.
P93
Unit 2 Lesson 1 Mitosis
Around and Around
P94-95
What are the stages of the cell cycle?
Unit 2 Lesson 1 Mitosis
P94-95
What are the stages of the cell cycle?
• Interphase is the stage in the cell cycle during which
the cell is not dividing.
• The cell grows to about twice the size it was when it
was first produced.
• It produces various organelles and engages in normal
life activities.
• Changes that occur during interphase prepare a
cell for division.
• DNA is duplicated
Unit 2 Lesson 1 Mitosis
P94-95
What are the stages of the cell cycle?
• In eukaryotic cells, mitosis is the part of the cell cycle
during which the nucleus divides.
• Mitosis results in two nuclei that are identical to the
original nucleus.
• Chromosomes condense from chromatin
• When mitosis is complete, the cell has two identical
sets of chromosomes in two separate nuclei.
• Prophase, Metaphase, Anaphase, Telophase,
Unit 2 Lesson 1 Mitosis
P94-95
What are the stages of the cell cycle?
• Cytokinesis is the division of the parent cell’s cytoplasm.
• Cytokinesis starts during the last step of mitosis and
eventually forms two complete cells.
• Cell membrane pinches inward between the new nuclei.
Eventually, it pinches all the way forming two complete
cells
• In cells that have a cell wall, a cell plate forms during
cytokinesis. The cell plate separates the cell into two new
cells.
Unit 2 Lesson 1 Mitosis
P94-95
Around and Around
What are the stages of the cell cycle?
Interphase
Mitosis
Cytokinesis
In Private, My
Amazing
Teacher Cries
Normal
Cellular
activities
take place
Cell Grows
Larger in
size
Produces
various
organelles
DNA gets
duplicated
Unit 2 Lesson 1 Mitosis
Phasing Out
P96-97
Mitosis
What are the phases of mitosis?
• There are four phases of mitosis: prophase,
metaphase, anaphase, and telophase.
• By the end of the four phases, the cell will have
two identical nuclei.
Unit 2 Lesson 1 Mitosis
P96-97
What are the phases of mitosis?
• In (1) prophase, the
chromatin in the nucleus
condenses into
chromosomes. The
membrane around the
nucleus breaks down.
• In (2)metaphase,
the chromosomes line
up in the middle of
the cell.
Unit 2 Lesson 1 Mitosis
P96-97
What are the phases of mitosis?
• In (3) anaphase, the
chromatids of each
chromosome are pulled
to opposite sides of the
cell.
• In (4)telophase, a new
nuclear membrane forms
around each group of
chromosomes, which become
less condensed.
• Cytokinesis begins during
this phase.
Unit 2 Lesson 1 Mitosis
P96-97
What are the phases of mitosis?
• After mitosis, cytokinesis results in two new cells,
and the two new cells start the cell cycle again.
Cyto
=
hollow
vessel
Kinesis = division
Mitosis
Cytokinesis