Transcript The Cell cycle & Mitosis

Ch. 5.1
At
the end of this lesson, students
will be able to…
• List the main stages of the cell cycle
in order
• Explain the main function of each
stage
• Describe factors that determine
division rate and cell size.
Prokaryotes
Eukaryotes
Nucleus
No
Yes
Chromosomes
Single, circular
More than one
Membrane bound
organelles
No
Yes
Mitochondria
No
Yes
Microtubules
No
Yes
Mitosis
No (Binary fission)
Yes
Examples
Bacteria
Animals, plants…
 The
cell nucleus is where eukaryotes
store their DNA
 DNA is what carries the instructions for
how to build a new cell down to every
detail – like the blueprints for a house
 The nucleus is surrounded by a
membrane called the nuclear envelope
 Inside the nucleus is the nucleolus which
is the site of rRNA transcription
 Fig
2.2, Pg. 131
 DNA
is in the form of double helix
strands
• If we stretched out human DNA strands from
ONE cell it would be 6.5 feet long
 In
order to organize these strands of
DNA, they are wrapped around proteins
called histones.
 Wrapping
DNA around histones isn’t
enough
 DNA/histone strands are twisted into
coils called chromatin
 Chromatin is twisted tighter and tighter
until it forms a neatly packed chromatid
 Chromatids duplicate during the cell
cycle to form the X shaped chromosomes
we generally see
 The
centromere is the pinched region of
the chromosome that holds the sister
chromatids together
 The kinetochores are the attachment
point for spindle fibers
Definition: The
cell cycle is the
regular pattern of growth, DNA
duplication, and cell division
that occurs in EUKARYOTIC
cells.
Interphase
includes:
• G1 (Gap 1)
• S (Synthesis)
• G2 (Gap 2)
Mitosis
includes:
• M (Mitosis)
• Cytokinesis
The
cell spends most of its time in
G1
This is when the cell carries out
its normal functions
Cells also GROW in size
Organelles replicate
The cell gets ready for the S stage
Synthesis
only begins if the cell
passes the checkpoint at the end
of G1
During the synthesis stage, DNA
is duplicated
At this point, DNA is still loosely
organized in the nucleus
G2
is another period of cell growth
and normal function
G2 also includes a checkpoint that
the cell must pass to enter mitosis
Definition: the
division of the
cell nucleus and its contents
(DNA)
• Mitosis is broken in 4 phases we
will learn about later
Cytokinesis
is the actual separation
of the cell into two identical
daughter cells
Literally
means “splitting of the
cytoplasm”
 What
are the 2 major phases of the cell
cycle?
 What percentage of time do most cells
spend in interphase?
 What is the non-dividing state called?
• Why do cells enter this state?
 What
is the function of histones?
 How many chromosomes do human
cells have to duplicate?
Catch
up: Section 5.1
• **FAQ #5 – Page 129**
• Fill in missing notes (powerpoints
on website)
For
tomorrow: Section 5.2
• FAQ #2 – Page 134
Ch. 5.2
At
the end of this lesson, students
will be able to…
• Describe what happens to DNA
during cell division
• List the phases of mitosis and
cytokinesis in order
• Explain major events in each phase
 The
M-Phase,
mitosis, can
be broken
down into
four stages
 FIRST: Number
off from 1 – 5
 SECOND: Find
the table in the back with
your number and become the “expert” on
that phase.
 THIRD: Mingle
with your classmates until
you have information on each phase of the
worksheet
 LAST: Once
your worksheet is filled in,
return to your seats
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
 http://www.youtube.com/watch?v=C6hn3s
A0ip0
 How long does mitosis typically last?
 Where do spindle fibers come from?
 T or F: The nucleolus breaks down in
prophase.
 Where do spindle fibers/microtubules
attach to?
 In what phase are sister chromatids
separated?
 T or F: new nuclear membranes form during
telophase.
 What does the contractile ring cause?
Pee
MAT
Parties (on) Mondays Aren’t That
Cool
Presidents May Admire The Cabinet
Please Make A Taco Cake
Please Make A Tasty Chicken
Play Makes A Toddler Crazy!
Personal
Money And Time Care
Parties
Make Aaron Totally Crazy
Purple
Monkeys Attack The Cat
Play
Mates Are Totally Cute
Prokaryote
cells divide faster than
eukaryotes
Cells that have a short “life span”
need to divide faster to replace dead
cells
• What types of cells die quickly?
• What types live a long time?
 DNA
 Cell
packaging (1.75 mins)
signals, Growth factors, and Healing
(13 min)
Hand
Blue
in mitosis activity packet
mitosis packets – Thursday 2/21
Powerpoints
Test
and flashcards online
– probably on Friday 3/1
• Note packet will be collected on test day
Page 128 - Figure 1.2 Cell Life Span
CELL TYPE
APPROXIMATE LIFE SPAN
Skin cell
2 weeks
Red blood cell
4 months
Liver Cell
300 – 500 days
Intestine – Internal lining
4 – 5 days
Intestine – muscle and other tissues
16 years
Would
a skin cell have a long
or short G1 stage compared
to other cell types? Explain.
Cells
must be BIG enough to include
all of the necessary parts, but SMALL
enough to have the correct ratio of
membrane surface area to volume
Membrane
surface area allows
diffusion and osmosis to take place
See
fig 1.3 on page 129
 Demo
– How does size affect the cell??
Catch
up:
• 5.1 – FAQ #5 and 5.2 – FAQ #2
• Fill in missing notes (powerpoints
on website)
For
tomorrow:
• Read 5.3 and do FAQ #5 page 139
What
limits the maximum size
of a cell? The minimum size?
Ch. 5.3
At
the end of this lesson,
students will be able to…
• Identify factors that regulate the
cell cycle
• Explain cancer in terms of the
cell cycle
 The
cell cycle is like an assembly line at
a factory – Quality checks need to be
made along the way to make sure
everything is being made correctly
• Three major checkpoints occur during the
cell cycle: at the end of G1, G2, and
metaphase
• If the cells fail any of these checkpoints
they will move into the NON-dividing
phase called G0
 Other
things that can regulate cell
division are:
• Cell to cell contact – when cells come into
contact with each other, cell division stops
• Apoptosis – programmed cell death. Cells that
are defective or no longer needed are shut down
and destroyed
• Growth factors – proteins and hormones that
stimulate growth and division
External
factors – Available
nutrients, chemicals from
environment
Internal
factors – Genetics, stress
(causes release of chemicals and
hormones inside the body)
Cell signals, Growth factors, and
Healing (13 min)
If
any methods of regulation
become dysfunctional – cell
division can run out of control
• Uncontrolled cell division is
called cancer
CANCER =
UNCONTROLLABLE
CELL
DIVISION!!!!!!!!!!!!!
 Define:
• Benign –
• Malignant –
• Metastasize• Carcinogens –
 Why
are tumors harmful?
 What are Oncogenes?
 What is the difference between radiation
and chemotherapy?
 Tumor
Growth
Oncogenes
– genes that have the
ability to cause cancer
Normally these genes are inactive or
expressed at healthy levels
• BUT – if a mutation occurs, even a single base
pair, the function of this gene can change to
produce cancerous cell division
Genes
that keep cancer turned
off
• If these genes mutate, their normal
function changes and they can’t keep
cancer away
P53
– tumor suppressor on
chromosome 17
 When
normal it keeps damaged cells
from replicating – Damaged DNA is a
major cause of cancer so if these cells
aren’t stopped, cancer can develop
 About
50% of human cancer is associated
with this gene – these cancers are
generally the most aggressive
Human
chromosomes –
Cancer related
genes written in
red
1920 - 1951
North County High School freshman Jack Andraka
earned the grand prize at the Intel International
Science and Engineering Fair for creating a test
that can detect early-stage pancreatic cancer
with 90% accuracy and at a cheaper rate than
other tests.
“It detects an abnormal protein that you find in the
blood when you have a pancreatic cancer,” Dr.
Anirban Maitra, professor of pathology, oncology
and chemical and biomolecular engineering at
Johns Hopkins School of Medicine, told CBS
affiliate WJZ-13. “He conceived this idea, and I
think the fact that he is 15 makes this whole story
more remarkable.”
Discuss:
• If a child was born with defective
growth hormone receptors, how
would development be affected?
Catch up:
• 5.1-5.3 with FAQs
• Fill in missing notes (powerpoints on website)
For tomorrow:
• Re - read Pg 138-139 and the “career” box on
pg. 276
For Monday:
• Read 5.4 and do FAQ # 3 page 142
Ch. 5.4
At
the end of this lesson, students
will be able to…
• Identify at least one organism that uses
asexual reproduction
• Explain the outcome of asexual
reproduction
• Explain the advantages and
disadvantages of asexual reproduction
 Requires
a male and female to donate
sperm and eggs
• Sperm and eggs are specialized cells called
gametes
• Gametes carry the genetic information of each
parent
• When these gametes come together, the genetic
information is combined to create a UNIQUE
genetic combination and therefore a unique
individual
Definition: The
creation of
offspring from a single parent and
does not involve the joining of
gametes.
• These offspring are genetically
identical to each other AND to the
single parent.
 Prokaryotes
(no nuclei) use asexual
reproduction
 Most bacteria only have a single, circular
chromosome – makes reproduction very
fast!
• Bacteria
 The
chromosome is replicated, separated
and the cell divides in half
• This is called BINARY FISSION (pg. 140)
 We
normally think of asexual
reproduction as a prokaryotic trait – But
there are some eukaryotes that use it too
 Three examples of eukaryotic asexual
reproduction are:
• Budding
• Fragmentation
• Vegetative reproduction
 In
budding, the single celled organism
grows a “clone” that eventually breaks off
and becomes an individual
 Yeast (a fungus), hydra (a multicellular
aquatic organism)
 Fig 4.3, Pg. 142
Fragmentation, the
parent splits
into pieces and each piece can
become its own individual
• Certain worms can do this, starfish
Vegetative
Reproduction – the
plant version of fragmentation
• Plant cuttings, runners
Asexual
 Pros:
• Fast
• Don’t need a partner
• Less energy input than
sexual
 Cons:
• No genetic diversity –
Risky in a changing
environment
Sexual
 Pros:
• Offspring are
genetically unique –
have a better chance
at adapting
 Cons:
• Slower
• Need partner
Some
organisms have the ability to
switch between sexual and asexual
reproduction.
• What might cause the organism to do
this?
• How does this benefit the organism?
Catch
up:
• 5.1-5.4 with FAQs
• Fill in missing notes (powerpoints
on website)
For
tomorrow:
• Read 5.5 and do FAQ #5 page 147
Ch. 5.5
At
the end of this lesson, students
will be able to…
• Explain how cells differentiate in
terms of genetics and specialized
cells
• Identify different types of stem
cells and why they are important in
terms of function and medical
possibilities
If
we all start out as a single cell
that multiplies by MITOSIS, how
do we develop skin, muscles,
bones, hair??
Cellular
Differentiation!
As
the body forms and cells divide
and grow, certain genes within the
DNA are switched on or off causing
the cell to commit to a specific
function
• This function determines which tissue, organ,
and system that the cell will be a part of
• Fig 5.2 Pg. 145
The
book uses the example of your
DNA being like a cookbook and
genes are like all of the different
recipes
• When a cell is ready to differentiate it “reads”
a specific gene that changes its development
 Video
 Tissues: are
groups of cells that work
together to perform a similar function
 Organs: are
groups of tissues that work
together to perform a specific function or
related functions
 Organ
systems: are organs that carry
out similar functions
Stem
cells are a unique type of body
cell that have the ability to:
• Divide and renew themselves for long
periods of time
• Remain undifferentiated
• Develop into a variety of specialized
cell types
 Stem
cells are classified by their
potential to develop into differentiated
cell types
• Totipotent: can grow into ANY other cell type
• Pluripotent: can grow into any cell type EXCEPT
a totipotent stem cell
• Multipotent: can develop into cells within a
specific range (ex: if the range is blood cells, it
cannot become a brain cell)
 See
fig. 5.3, Pg 146
The
potential of these stem cells
depends on where they come from
• Embryonic – These cells have the ability to
become any cell or tissue type in the body,
pluripotent
• Adult – These cells can become the tissue
they were taken from (liver, brain, blood etc.),
multipotent
 Diseases
and trauma that could benefit
from stem cell research:
• Parkinson's disease,
• Diabetes,
• Traumatic spinal cord injury,
• Duchenne's muscular dystrophy,
• Heart disease
• Vision and hearing loss
• Burn victims
• Cancer patients
• Liver disease
This
is the END OF THE UNIT!
• Finish missing readings and FAQs
• 5.1#5 - 5.2#2 - 5.3#5 - 5.4#3 -
5.5#5
• Fill in missing notes (powerpoints
on website)
• Be sure to have: blue mitosis
packet, cancer test, stem cell
packet
A. The order of the cell
cycle phases
B. The major events of the
cell cycle phases
C. Things that affect the
rate of division
D. Cell size
E. The FAQs
F. Regulation of the cell
cycle
G. Cancer and the cell
cycle
H. Asexual reproduction in
prokaryotes
I. Asexual reproduction in
eukaryotes
J. Differentiation of cells
K. Stem cells
L. Mitosis