Download The Cell Cycle: A closer look!

THE CELL CYCLE: A
CLOSER LOOK!
BIOLOGY 12
FUNNY?
REVIEW (FROM LAST CLASS):
WHICH STAGE IS LONGEST?
INTERPHASE
• Aka the resting phase (but not really…)
• Essentially, the cell is in between divisions and is
carrying out maintenance activities of the cell
• Made up of 3 sub-phases:
1. G1 phase
2. S phase
3. G2 phase
INTERPHASE: G1 PHASE
• 1st growth phase
• Cell mature by making more cytoplasm &
organelles
• Cell carries on its normal metabolic activities, such
as synthesising proteins
INTERPHASE: S PHASE
• Synthesis stage
• DNA is copied or replicated
Two
identical
copies of
DNA
Original DNA
INTERPHASE: G2 PHASE
• 2nd Growth Stage
• Occurs after DNA has been copied
• All cell structures needed for division are completed
(e.g. centrioles)
• Both organelles & proteins continue to be
synthesized
MITOSIS
• Aka karyokinesis
• Division of the nucleus
• Only occurs in eukaryotes
• Made up of 4 phases:
1.
2.
3.
4.
Prophase
Metaphase
Anaphase
Telophase
MITOSIS: PROPHASE
• Early prophase:
• Centrioles: make spindle fibres and move towards opposite
plates
• Chromosomes shorten and thicken (now visible under a
microscope)
• Late prophase:
• Centrioles reach poles
• Nuclear membrane (envelope) & nucleolus start to
disappear
MITOSIS: METAPHASE
• Spindle fibres attach to centromeres
• Sister chromatids (doubled chromosomes) line up at
equator (middle of cell)
• Guided by spindle fibers
MITOSIS: ANAPHASE
• Centromeres divide in
two
• Spindle fibers contract
and pull sister
chromatids towards
opposite ends of cell
(pole)
• Each pole (future
daughter cells) will have
an identical set of
chromosomes
MITOSIS: TELOPHASE
• Sister chromatids at
opposite poles
• Spindle disassembles
• Nuclear membrane forms
around each set of sister
chromatids
• Nucleolus reappears
• Chromosomes loss their
distinct outlines reappear
as chromatin
IN PICTURES:
• Prophase
• Metaphase
• Anaphase
• Telophase
15
CYTOKINESIS:
• Means division of the cytoplasm
• Division of cell into two, identical halves called
daughter cells
• Would this happen the same way in plants and
animal cells? Why or why not?
• In plant cells, cell plate forms at the equator to divide cell
• In animal cells, cleavage furrow forms to split cell
CYTOKINESIS
Cleavage furrow
in animal cell
Cell plate in animal
cell
17
HELPFUL HINT?
•
•
•
•
•
•
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
IPMATC
Amimation:
• http://www.youtube.com/watch?v=AhgRhXl7w_g&
feature=fvsr
TO DO:
• Mitosis colouring sheet
• Labelling sheet
• Nelson Bio 11 Book
• #1 to 9