Download CELL CYCLE

THE CELLULAR BASIS
OF INHERITANCE
CHAPTER 9
Why Is Cell Reproduction
Essential for Life?
#1) Maintain/Heal the Body
– TO REPLACE LOST OR DAMAGED
CELLS
Example:
Every minute of the day we lose about
30,000 to 40,000 dead skin cells off
the surface of our skin.
Why Is Cell Reproduction
Essential for Life?
#2) GROWTH
- Increase body size by
increasing the number
of cells in the body
Why Is Cell Reproduction
Essential for Life?
#3) REPRODUCTION = TO CREATE
A COMPLETE NEW ORGANISM.
2 TYPES OF REPRODUCTION:
a) ASEXUAL
b) SEXUAL
ASEXUAL REPRODUCTION
How Many
Parents?
• SINGLE
PARENT
• OFFSPRING ARE
GENETICALLY
IDENTICAL TO EACH
OTHER AND TO
PARENT.
• SEEN IN
UNICELLULAR
ORGANISMS AND
SOME
MULTICELLULAR
ORGANISMS SUCH AS
PLANTS,FUNGI, AND
SOME ANIMALS LIKE
SPONGES AND
STARFISH.
SEXUAL REPRODUCTION
• 2 PARENTS
• GENETIC MATERIAL
(CARRIED IN EGG AND
SPERM) FROM EACH
PARENT COMBINES
• EACH OFFSPRING IS
GENETICALLY
DIFFERENT FROM
PARENTS
• Egg and Sperm are
produced through
cell division
REVIEW:
WHY DO CELLS DIVIDE
AND PRODUCE NEW
CELLS?
For Maintenance of the body
(multicellular organisms)
For Growth
(multicellular organisms)
For Reproduction
(multi- and unicellular organisms)
The
“CELL CYCLE”
• STARTS WHEN A CELL IS
“BORN” & ENDS WHEN IT
REPRODUCES.
• CELL CYCLE PRODUCES
CELLS NEEDED FOR
GROWTH & MAINTENANCE
OF THE BODY
The
“CELL CYCLE”
Cell is not
dividing
(Most of
the time)
Cell is
dividing
Nucleus
divides
first
Cytoplasm
divides
last
The
“CELL CYCLE”
• HAS 2 MAIN STAGES:
•INTERPHASE
– cell isn’t dividing
•MITOTIC PHASE
– cell is dividing
INTERPHASE
•WHAT IS IT?
•WHAT HAPPENS
DURING IT?
INTERPHASE
• LONGEST STAGE (90%
OF THE CELL CYCLE)
• THE CELL GROWS &
PERFORMS ITS JOB AS A
CELL
INTERPHASE
• IN THIS STAGE
DNA EXISTS AS A
MASS OF VERY
LONG THIN FIBERS
CALLED
CHROMATIN
_________________.
INTERPHASE
• CELL ALSO PREPARES
TO REPRODUCE (CELL
DIVISION) BY
INCREASING ITS
NUMBER OF
ORGANELLES & BY
MAKING COPIES OF ALL
DNA
ITS _____________.
muy importante!!!
•EACH DNA STRAND IS COPIED & THE 2 COPIES ARE
CENTROMERE
JOINED AT ONE SPOT CALLED THE __________________.
DNA IN CHROMATIN FORM
What Happens Next?!
•After the cell has
made all its
preparations,
then it divides!
•On to the Mitotic
Phase!!
MITOTIC PHASE
• SHORTEST
STAGE of the
CELL CYCLE
• THIS IS WHERE 1
CELL DIVIDES
INTO 2 CELLS
• OCCURS IN 2
STEPS:
1) MITOSIS
2) CYTOKINESIS
MITOSIS
• All about the Nucleus!
• In this stage the
nucleus divides
into 2 and the
chromosomes are
evenly divided up.
• Each daughter nucleus
receives a complete
set of chromosomes
MITOSIS
• ALL THE DUPLICATED
CHROMATIN FIBERS
NOW COIL UP (GET
SHORTER &
THICKER) & ARE
CALLED
CHROMOSOMES .
____________________
• EACH CHROMOSOME
IS MADE UP OF 2
IDENTICAL HALVES
SISTER
CALLED ______________
CHROMATIDS
.
SISTER
CHROMATIDS
MITOSIS
• The SISTER CHROMATIDS SEPARATE &
GO TO OPPOSITE ENDS OF THE CELL
FORMING 2 NEW “DAUGHTER” NUCLEI
CYTOKINESIS
• The CYTOPLASM
DIVIDES
BETWEEN THE 2
NEW
“DAUGHTER”
NUCLEI FORMING
2 NEW CELLS
The
“CELL CYCLE”
Cell is not
dividing
(Most
of
INTERPHASE
the time)
Cell is MITOTIC
dividing PHASE
Nucleus
divides
first
MITOSIS
Cytoplasm
divides
last
CYTOKINESIS
Name the Structure!
?
Centromere
?
Centromere
?
?
?
?
Chromosomes
SISTER
CHROMATIDS
?
CELL
CYCLE
______________ =
series of events that cells go
through as they grow and
develop
cells alive cell cycle
CELL CYCLE
INTERPHASE – non-dividing phase
G1- Grow bigger
Cell is “doing its job”
DNA is spread out as chromatin
S - Synthesis (copy DNA)
& chromosomal proteins
G2- Grow bigger, make organelles &
molecules needed for cell division
CELL DIVISION
MITOSIS – Nuclear division
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis – Cytoplasm divides
G0 – cell stops dividing
(Ex: nerve cell)
INTERPHASE (G1 - S - G2)
In between divisions
Cells are in this phase most of the time
Can see nucleus
DNA spread out as chromatin
Can’t see chromosomes
DNA gets copied (S)
Cell gets ready to divide
Pearson Education Inc publishing as Pearson Prentice Hall
PROPHASE
1st dividing phase
http://www.life.uiuc.edu/plantbio/102/lectures/08mit&veg102.html
DNA scrunches into chromosomes
Centrioles appear in centrosome region
& move to poles
Nuclear membrane & nucleolus disappear
Spindle fibers form & attach to
chromosomes
CENTROSOME
________
region organizes spindle
Spindle MICROTUBULES are part of cytoskeleton
http://www.coleharbourhigh.ednet.ns.ca/library/organelle_worksheet.htm
METAPHASE
Chromosomes line up in
middle
___________
Images from:
Pearson Eduction Ince; Publishing as Pearson Prentice Hall
http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0247.JPG
ANAPHASE
Centromeres split
apart
Centrioles pull chromatids_______
Images from:
Pearson Eduction Ince; Publishing as Pearson Prentice Hall
http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0247.JPG
TELOPHASE (reverse prophase steps)
two nuclei
See ______
Nuclear membrane & nucleolus return
Chromosomes spread out as chromatin
Centrioles disappear
Spindle fibers disappear
Images from:
Pearson Eduction Ince; Publishing as Pearson Prentice Hall
http://www2.bc.cc.ca.us/cnewton/Biology%2011/Mitosis.html
CYTOKINESIS
Cytoplasm splits into 2 cells
ANIMAL CELLS pinch cytoplasm in two
with a ______________________
CLEAVAGE FURROW
CYTOKINESIS
Cytoplasm splits into 2 cells
PLANT CELLS can’t pinch because
they have a sturdy ____________
CELL WALL
Plant cells separate cytoplasm by
CELL PLATE
growing a _______________
down the middle.
http://www.eastcentral.edu/acad/depts/BI/plant_mitosis_nolabels.html
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase