Download 4.4 Presentation: Mitosis

Cell Cycle - Handout
• Complete the assignment.
• Raise your hand to be checked off for completion.
• Glue/tape the assignment into your notebook
making sure that the stamp is visible
Mitosis Foldable
Understanding Mitosis
• Prophase
• (1st phase of mitosis)
• Chromatin condenses to form visible chromosomes
• 1 chromosome = 2 sister chromatids
• (packaged copies of DNA from S-phase of interphase)
• Nuclear envelope disappears
• Important structures for completion of the cell cycle
appear:
• Centrioles: send out spindle fibers
• Spindle Fibers: attach to sister chromatids to pull apart
• Centromeres: hold 2 sister chromatids together
Understanding Mitosis
• Metaphase
• (“M” is for Middle)
• Chromosomes move to the middle of the cell
• Still paired as sister chromatids
• Attached in center with a centromere (also to spindles)
Understanding Mitosis
• Anaphase
• (“A” is for Apart)
• Centromeres break and sister chromatids pull apart
• Spindle fibers shorten and pull chromatids (now each is
an individual chromosome) toward opposite sides of cell
Understanding Mitosis
• Telophase
• Begins when chromosomes reach opposite poles of cell
• Chromosomes de-condense to less visible chromatin
and nuclear envelope and organelles re-appear
• Cell begins to pull apart and prepares for division
Understanding Mitosis
• Cytokinesis
• Animal Cells – cleavage
furrow forms
• Cell membrane pinches
in to divide cells
• Plant Cells – cell plate
• Forms a new portion of
the cell wall
So How Do I Remember All of
These?
• Prophase: hands together with fingers interlocked
• Prometaphase: hands together with fingers
extended
• Metaphase: hands overlapping each other with
fingers extended
• Anaphase: hands side by side with fingers extended
(only your middle fingers should be touching)
• Telophase: hands closed in a fist side by side
• Cytokinesis: hands separated in a fist
Understanding Mitosis
• Cell Cycle Regulation
• Uncontrolled cell division results in tumors / cancer
• Chemicals monitor each phase of the cycle
• Reasons why cells may divide uncontrollably:
• Radiation, carcinogens, mutated genes
Cell Cycle and Mitosis
Review
Get 1 partner
Get a whiteboard and a marker
Review your notes for the first five minutes of class
with your partner.
Describe what occurs
during cytokinesis
What phase of mitosis is
represented by the picture
below?
Why do plant cells have a
cell plate and animal cells
have a cleavage furrow?
Describe what occurs
during prophase
What phase of mitosis is
represented by the picture
below?
Describe what occurs
during anaphase
Describe what occurs
during the first gap phase
Describe what occurs
during metaphase
What phase of mitosis is
represented by the picture
below?
Describe what occurs
during the second gap
phase
Why is prokaryotic cell
division simpler than
eukaryotic cell division?
Describe what occurs
during telophase
Describe what occurs
during the synthesis phase
What is the end product
of mitosis?
Chromosomes move to the
middle of the cell during
which phase?
What structure holds sister
chromatids together?
During which phase does
the nuclear envelope
disappear?
During which phase do
chromosomes first become
visible?
List the phases of
mitosis in order
Describe what occurs
during interphase
What is cancer?
Describe what occurs
during interphase
What phase of mitosis is
represented by the picture
below?