Topic 2: Cells
2.1.1 Outline the cell theory.
Discuss the theory that living
organisms are composed of cells.
 The Cell Theory states that:

– All organisms are composed of one or more
cells.
– All cells arise from pre-existing cells.
– All vital functions of an organism occur
within cells.
– Cells are the most basic unit of life.
– Cells contain hereditary information. Why?
2.1.2 Discuss the evidence for
the cell theory.
What is Evidence?
 What is a theory?
 Evidence for Cell theory:
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– Living tissues= composed of cells
– Cells of an organism can sometimes survive on
their own but smaller cell components can
NOT.
– Classic experiments showed that spontaneous
generation of life= impossible.
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The cell theory has amassed tremendous
credibility through the use of the microscope in
the following:
Robert Hooke- studied cork and found little tiny
compartments that he called cells
Antonie Van Leeuwenhoek- observed the first
living cells, called them 'animalcules' meaning
little animals
Schleiden- stated that plants are made of
'independent, separate beings' called cells
Schwaan- made a similar statement to
Schleiden about animals
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When scientists started to look at the structures of
organisms under the microscope they discovered that all
living organisms where made up of these small units which
they proceeded to call cells. When these cells were taken
from tissues they were able to survive for some period of
time. Nothing smaller than the cell was able to live
independently and so it was concluded that the cell was the
smallest unit of life. For some time, scientists thought that
cells must arise from non-living material but it was
eventually proven that this was not the case, instead they
had to arise from pre-exsisting cells. An experiment to
prove this can be done as follows:
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Take two containers and put food in both of these
Sterilize both of the containers so that all living organisms
are killed
Leave one of the containers open and seal the other closed
What will happen is that in the open container mold will
start to grow but in the container that was sealed no mold
will be present. The reason for this is because in the open
container, cells are able to enter the container from the
external environment and start to divide and grow.
However, due to the seal on the other container no cells will
be able to enter and so no mold will develop, proving that
cells cannot arise from non-living material.
Exceptions to aspects of the
theory?
 Skeletal muscle –
multinucleate cytoplasm
 Some fungal hyphaemultinucleate cytoplasm.
 Extracellular material
(material outside the cell
membrane), such as teeth
and bone, forms a
significant part of the body.
 Some biologists consider
unicellular organisms to be
acellular.
Do you think these constitute
exceptions to cell theory?
Justify your answer.
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Note: this slide=not in new
syllabus…
2.1.3 State that unicellular
organisms carry out all the
functions of life.
 Discussion: What are the necessary
functions of life?
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C—Made of one or more than on cell
 H—Maintain Homeostasis
 E—Metabolize energy
 D—Made of DNA
 D—Develop and Grow
 A—Adapt
 R—Reproduce
 S—Respond to stimuli
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2.1.4
Compare the relative sizes of molecules, cell
membrane thickness, viruses, bacteria, organelles
and cells, using appropriate SI units.
“Molly Membrane’s Virus Backed Off Most Cells”

Molecules (1 nm) (Smallest)
Cell membrane thickness (10 nm)
Viruses (100 nm)
Bacteria (1 µm)
Organelles (<10 µm)
Most cells (<100 µm) (Largest)
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Interactive http://www.cellsalive.com/howbig.htm
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 2.1.5
Calculate linear
magnification of
drawings.
– Drawings should
show cells and cell
ultrastructure.
 Include:
– A scale bar: |------| =
1 µm
– Magnification: ×250
 To
calculate
magnification:
– Magnification =
Measured Size of
Diagram ÷ Actual Size
of Object
2.1.6
Explain the importance of
the surface area to
volume ratio as a
factor limiting cell size.

– The rate of
exchange of
materials
(nutrients/waste)
and energy (heat) is
a function of its
surface area.
(Why?)
– As cell size
increases, the
surface area to
volume ratio
decreases
 This can make
the exchange
rate inadequate
for large cells
– Cell size, therefore,
remains small
2.1.7 State that multicellular organisms show
emergent properties.

Multicellular organisms show emergent
properties. For example: cells form tissues,
tissues form organs, organs form organ systems
and organ systems form multicellular organisms.
The idea is that the whole is greater than the
composition of its parts. For example your lungs
are made of many cells. However, the cells by
themselves aren’t much use. It is the many cells
working as a unit that allow the lungs to perform
their function.
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Define tissue, organ and
organ system.
Tissue: An integrated
group of cells that share
stucture and are adapted
to perform a similar
function.
Organ: A combination of
two or more tissues which
function as an integrated
unit, performing one or
more specific functions.
Organ system: A group
of organs that specialize in
a certain function together.
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2.1.8
Explain that cells in
multicellular
organisms
differentiate to
carry out
specialized
functions by
expressing some of
their genes but not
others.
– Differentiation:
becoming specialized
in structure and
function.
– Supporting examples?
– Multicellular organisms
show emergent
properties (What??)
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See Previous
slide…
Video: http://www.pbs.org/wgbh/nova/sciencenow/archive/title-m-z.html
2.1.9 State that stem cells retain the capacity to divide and
have the ability to differentiate along different pathways.
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Stem cells
– Retain the capacity to divide
– Have the ability to differentiate
along different pathways.
Therapeutic Use:
– Many possibilities
 Repair of damaged tissue
– Actual uses
 Restore neural insulation tissue
in rats.
 Use of umbilical cord blood stem
cells for leukemia patients.
– Sources and ethical issues:
 Embryonic
 placenta/umbilical cord
 Many other tissues have stem
cells
 Pluripotent vs.
totipotent/omnipotent
Video: http://www.pbs.org/wgbh/nova/sciencenow/archive/title-m-z.html
2.1.10 Outline one therapeutic use of stem cells.
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Bone marrow transplants are one of the many therapeutic uses of stem
cells. Stem cells found in the bone marrow give rise to the red blood cells,
white blood cells and platelets in the body. These stem cells can be used
in bone marrow transplants to treat people who have certain types of
cancer.
When a patient has cancer and is given high doses of chemotherapy, the
chemotherapy kills the cancer cells but also the normal cells in the bone
marrow. This means that the patient cannot produce blood cells. So before
the patient is treated with chemotherapy, he or she can undergo a bone
marrow harvest in which stem cells are removed from the bone marrow by
using a needle which is inserted into the pelvis (hip bone). Alternatively, if
stem cells cannot be used from the patient then they can be harvested
from a matching donor. After the chemotherapy treatment the patient will
have a bone marrow transplant in which the stem cells are transplanted
back into the patient through a drip, usually via a vein in the chest or the
arm. These transplanted stem cells will then find their way back to the
bone marrow and start to produce healthy blood cells in the patient.
Therefore the therapeutic use of stem cells in bone marrow transplants is
very important as it allows some patients with cancer to undergo high
chemotherapy treatment. Without this therapeutic use of stem cells,
patients would only be able to take low doses of chemotherapy which
could lower their chances of curing the disease
.
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When a patient has cancer and is given high doses of
chemotherapy, the chemotherapy kills the cancer cells but also
the normal cells in the bone marrow. This means that the patient
cannot produce blood cells. So before the patient is treated with
chemotherapy, he or she can undergo a bone marrow harvest in
which stem cells are removed from the bone marrow by using a
needle which is inserted into the pelvis (hip bone). Alternatively, if
stem cells cannot be used from the patient then they can be
harvested from a matching donor. After the chemotherapy
treatment the patient will have a bone marrow transplant in which
the stem cells are transplanted back into the patient through a
drip, usually via a vein in the chest or the arm. These
transplanted stem cells will then find their way back to the bone
marrow and start to produce healthy blood cells in the patient.
Therefore the therapeutic use of stem cells in bone marrow
transplants is very important as it allows some patients with
cancer to undergo high chemotherapy treatment. Without this
therapeutic use of stem cells, patients would only be able to take
low doses of chemotherapy which could lower their chances of
curing the disease.
2.1.10 - Outline one use of therapeutic stem cells .
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1.Non-Hodgkins Lymphoma is a
cancerous disease of the lymphatic
system:
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Outline of the disease:
1. patient requires heavy does of
radiation and or chemotherapy. This will
destroy health blood tissue as well as the
diseased tissue.
2. Blood is filtered for the presence of
peripheral (blood-forming) stem cells.
Cells in the general circulation that can
still differentiate into different types of
blood cell otherwise known as stem cells.
3. Bone marrow can be removed before
treatment.
4. Chemotherapy supplies toxic drugs to
kill the cancerous cells.
5. Radiation can be used to kill the
cancerous cells. In time however the
cancerous cells adapt to this treatment so
that radiation and chemotherapy are
often used together.
6. Post radiation/ chemotherapy means
that the patients health blood tissues is
also destroyed by the treatment.
7. Health stem cells or marrow cells can
be transplanted back to produce blood
cells again

Bone marrow transplants
only work because what
you are actually
transplanting is the
hematopoietic (blood cells
that give rise to all the
other blood cells) stem
cells in the marrow.
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peripheral blood stem
cells-- method of replacing
blood-forming stem cells
destroyed, for example, by
cancer treatment.
Immature blood cells
hematopoietic (blood cells
that give rise to all the
other blood cells) stem
cells in the circulating
blood that are similar to
those in the bone marrow
are collected by apheresis
from a potential donor.
Cord blood stem cells, can
be used in lieu of bone
marrow, making being a
donor FAR easier today
than in decades past.
2.2.1 Draw and Label a diagram of the Ultrastructure of
Eschrichia coli (E. coli) as an example of a Prokaryote
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Draw a generalized
prokaryotic cell as seen in
electron micrographs
The diagram should include:
– the cell wall,
– plasma membrane,
– cytoplasm,
– Pili
– Flagella
– Ribosomes
– nucleoid ( region
containing naked DNA).
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2.2.2 Anotate the diagram from
2.2.1 with the function of each
named structure
Cell Wall: Maintains the cell's
shape and give protection.
Plasma Membrane: Regulates
the flow of materials (nutrients,
waste, oxygen, etc.) into and out
of the cell.
Mesosome: A tightly folded
region of cell membrane. (has
attached proteins for
respiration/photosynthesis)
Cytoplasm: Holds and suspends
the cell's ribosomes and
enzymes. Region where
glycolysis occurs.
Ribosome: Protein synthesis.
Nucleoid region: Contains the
cell's genetic material (naked
DNA)
Slime capsule: Used as energy
storage
Flagella: Mobility
Pili: Interacting with other cells
Plasmid: Extra DNA which helps
with adaptations to the
environment
2.2.3 Identify the structures from 2.2.1 in
electron micrographs of E.Coli
2.2.4 State that prokaryote cells
divide by Binary Fission

Prokaryotic cells
divide by binary
fission
– Asexual
– splits directly into
two equal-sized
offspring, each with
a copy of the
parent's genetic
material.
FYI for future reference
 State that prokaryotes
show a wide range of
metabolic activity including
fermentation,
photosynthesis and
nitrogen fixation.
EX.
 Cyanobacteria (blue-green
algae)--photosynthesis.
 Bacteria can convert organic
substances into other organic
substances. (i.e., glucose to
lactic acid during anaerobic
respiration)
 Nitrogen fixation– convert N2
in air to ammonia.

Cyanobacteria
Video:
http://www.pbs.org/wgbh/nova/sciencenow/3
401/04.html
Bacteria
Harvard Animation
 Why
are cells cool?
 http://multimedia.mcb.harvard.edu/
Eukaryotic Cells
2.3.1Draw a
diagram to show
the
ultrastructure of
a generalized
animal cell (liver
cell) as seen in
electron
micrographs.
 Should include
free ribosomes
rough
smooth ER
Lysosome
Golgi apparatus
mitochondria
nucleus.
An Animal Cell
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Define organelle.
An organelle is a discrete
structure within a cell, and has
a specific function.
2.3.2 Annotate the diagram
from 2.3.1 with the funciton of
each named structure
– mitochondrion
– golgi body
– endoplasmic reticulum
– vacuole
– lysosome
– ribosome In contrast to the
other organelles, they are
not surrounded by a
membrane.
– centriole (Unique to animal
cells)
– chloroplast
EUKARYOTE CELL ULTRASTRUCTURE
Practice: What are
the respective
magnifications of the
cell as a whole and of
each of its organelles
in the following cell
picture?
Summary of the major cell organelles:
ORGANELLE
MAIN
FUNCTIONS
DIMENSIONS
Nucleus
Cell division,
protein
synthesis
10 µm diameter
Mitochondrion
Respiration
pathways
Chloroplast
Photosynthetic
pathways
Lysosome
Digestion,
recycling &
isolation
Golgi apparatus
Secretion,
reprocessing,
lysosome
synthesis
Cisternae:
0.5µm thick, l3µm diameter
Endoplasmic
Reticulum (ER)
Support, Golgi
apparatus
synthesis.
26 to 56 nm
thick
Ribosome
Protein
synthesis
1.0 to 12.5 µm
5 to 10 µm
diameter
0.5 to 3.0 µm
diameter
20 nm diameter
State one function of each of
these organelles: ribosomes,
rough endoplasmic reticulum,
lysosome, Golgi apparatus,
mitochondrion and nucleus.
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Ribosomes: protein synthesis
Rough endoplasmic reticulum
(rER): Packages proteins
Lysosome: digests old cell
parts, macromolecules (food)
and engulfed viruses/bacteria
Golgi apparatus: Modifies,
stores and routes products of
the endoplasmic reticulum.
Mitochondrion: cellular
respiration.
Nucleus: contains genetic
material –transcription occurs
here.
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Ribosomes: Found either floating free in the cytoplasm or attached
to the surface of the rough endoplasmic reticulum and in
mitochondria and chloroplast. Ribosomes are the site of protein
synthesis as they translate messenger RNA to produce proteins.
Rough endoplasmic reticulum: Can modify proteins to alter their
function and/or destination. Synthesizes proteins to be excreted
from the cell.
Lysosome: Contains many digestive enzymes to hydrolyze
macromolecules such as proteins and lipids into their monomers.
Golgi apparatus: Receives proteins from the rough endoplasmic
reticulum and may further modify them. It also packages proteins
before the protein is sent to it’s final destination which may be
intracellular or extracellular.
Mitochondrion: Is responsible for aerobic respiration. Converts
chemical energy into ATP using oxygen.
Nucleus: Contains the chromosomes and therefore the hereditary
material. It is responsible for controlling the cell. Transcription
occurs here.
2.3.3 Identify structures from 2.3.1 in
electron micrographs of liver cells
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1.
2.
3.
4.
5.
Nucleus
Mitochondria
Cell border
Nucleoli
Red blood cell
Another example
Prokaryotic cells vs. Eukaryotic cells
 Contain naked DNA vs. DNA associated with protein
DNA in cytoplasm vs. DNA enclosed in a nuclear envelope
No membrane-enclosed organelles vs. membrane-enclosed
organelles (e.g., mitochondria, chloroplasts)
 70S vs. 80S ribosomes
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No mitochondria vs. Mitochondria
 Circular DNA vs. Linear DNA
Flagella lack internal microtubules vs. Flagella have
microtubules.
No mitosis/Meiosis (Reproduce via Binary fission vs.
Mitosis/Meiosis
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2.3.5 State three differences between
plant and animal cells.
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Only plant cells have:
Cell walls
Chloroplasts
Large central vacuoles and tonoplast
Plasmodesmata (microscopic channels
which traverse the cell walls of plan cells
and some algal cells, enabling transport
and communication between them
Starch granules for storage of
carbohydrates
Only animal cells have:
Centrioles
Lysosomes—careful, I have read where some
plants have lysosomes.
Glycogen for storage of carbohydrate
Also: Plant cells usually have much less
cholesterol in their plasma membranes.
Remember--Cholesterol is required to build and
maintain membranes; it modulates membrane
Said a little differently
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Animal cells only have a plasma membrane and no cell
wall. Whereas plant cells have a plasma membrane and a
cell wall. Animal cells do not have chloroplasts whereas
plant cells do for the process of photosynthesis.
Animal cells store glycogen as their carbohydrate resource
whereas plants store starch.
Animal cells do not usually contain any vacuoles and if
present they are small or temporary. On the other hand
plants have a large vacuole that is always present.
Animal cells can change shape due to the lack of a cell wall
and are usually rounded whereas plant cells have a fixed
shape kept by the presence of the cell wall.
2.3.6 Outline two roles of
extracellular components
 Animal
cells
– Extracellular matrix (secreted
glycoproteins)
 Support
 Adhesion
 Movement
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2.3.6 Outline two roles of extracellular
components
Plant cell wall
– Main component= cellulose
 Cellulose molecules are arranged in bundles
 give the cell wall great tensile strength and allow
high pressures to develop inside the cell.
 Functions= structure, support, protection.
…State the composition and function of the plant cell wall. (Just
an FYI—not an IB component)
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Three layers:
– middle lamella (between adjacent cells– attachment)
– primary cell wall
– secondary cell wall (stronger– has lignin for strength)
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Functions= structure, support, protection.
Membranes
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2.4.1 Draw a diagram of the fluid mosaic model.
http://www.youtube.com/watch?v=Qqsf_UJcfBc
Diagram should show
– the phospholipid bilayer,
– cholesterol,
– glycoproteins,
– Integral proteins
– peripheral proteins.
– Be sure you use the term “phospholipid bi-layer, NOT cell membrane
2.4.2 Explain how the hydrophobic and hydrophilic
properties of phospholipids help to maintain the
structure of cell membranes.
Hydrophilic
-”water loving”
-phosphate heads
Hydrophobic
-”water-fearing”
-fatty acid tails
Phospholipid molecules make up the cell
membrane and are hydrophilic (attracted to
water) as well as hydrophobic (not attracted to
water but are attracted to other hydrophobic
tails). They have a hydrophilic phosphate head
and two hydrophobic hydrocarbon tails. Cell
membranes are made up of a double layer of
these phospholipid molecules. This is because in
water the hydrophilic heads will face the water
while the hydrophobic tails will be in the center
because they face away from the water. The
phospholipid bilayer makes the membrane very
stable but also allows flexibility. The
phospholipid in the membrane are in a fluid
state which allows the cell to change it’s shape
easily.
Functions of membrane proteins
Hormone binding sites.
 Enzymes
 Cell adhesion
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– Attachment to the cytoskeleton and
extracellular matrix
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Cell communication
– Signal transduction
– Cell-cell recognition
Channels for passive transport
 Pumps for active transport.
 Electron carriers
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Define diffusion

Diffusion: the
passive
movement of
particles from a
region of higher
concentration to
a region of lower
concentration,
as a result of the
random motion
Animation
of particles.
http://www.indiana.edu/~phys215/lecture/lecn
es/lecgraphics/diffusion2.gif
Define Osmosis
Osmosis: the passive movement of
water molecules, across a
selectively permeable membrane,
from a region of lower solute
concentration to a region of higher
solute concentration. (i.e. the
diffusion of water)
Remember: Lowers solute
concentration = higher water
concentration!!!
Hypertonic (hyperosmotic)
Hypotonic (hypoosmotic)
Isotonic (isoosmotic)
http://www.tvdsb.on.ca/westmin/sci
ence/sbi3a1/Cells/Osmosis.htm
effect of osmosis on cell animation
2.4.5 Explain passive transport across membranes in
terms of diffusion.
 Simple
diffusion
 facilitated diffusion.
– No ATP used
– Channel proteins (integral membrane
proteins)
– Down concentration/electrochemical
gradient
– Specific
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ex. Ion Channels in neurons
2.4.6 Explain the role of protein pumps and
ATP in active transport across membranes.
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Active transport is the
movement of substances
across membranes using
energy from ATP.
– moves substances against a
concentration gradient.
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Active transport
animations:http://www.bbc.co.uk
Carrier proteins– protein
pumps
Types of transport
2.4.6
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Active transport involves the movement of substances
through the membrane using energy from ATP.
The advantage of active transport is that substances can be
moved against the concentration gradient, meaning from a
region of low concentration to a region of high
concentration.
This is possible because the cell membrane has protein
pumps embedded it which are used in active transport to
move substances across by using ATP.
Each protein pump only transports certain substances so
the cell can control what comes in and what goes out.
2.4.7 Explain how vesicles are used to transport materials within a
cell between the rough endoplasmic reticulum, Golgi apparatus,
and plasma membrane.
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Proteins synthesized by
ribosomes
enter the rough endoplasmic
reticulum to be modified
Vesicles bud from rER and carry
the proteins to the Golgi
apparatus.
Golgi apparatus modifies the
proteins.
Vesicles bud off from the Golgi
apparatus and carry the modified
proteins to the plasma membrane
– This is a process called
exocytosis.
Endocytosis is a similar process
which involves the pulling of the
plasma membrane inwards so that
the pinching off of a vesicle from
the plasma membrane occurs and
then this vesicle can carry its
content anywhere in the cell.
Describe how the fluidity of the membrane allows it to
change shape, break and reform during exocytosis.
In exocytosis vesicles fuse with the plasma membrane.
The contents of the vesicles are then expelled. The
membrane flattens out again.
animations:http://www.bbc.co.uk/education/asguru/biology
/01cellbiology/05pathways/09endoexo/index.shtml
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In
Describe how the fluidity of the membrane
allows it to change shape, break and reform
during endocytosis
endocytosis part of
the plasma membrane
is pulled inwards.
A droplet of fluid
becomes enclosed
when a vesicle is
pinched off.
Vesicle can then
move through the
cytoplasm carrying its
contents.
Cell Division
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State that the celldivision cycle involves
interphase, mitosis, and
cytokinesis.
New cells are produced by
the division of existing cell,
remember the cell theory.
Interphase: DNA replication
and transcription occurs.
Also, normal cell life.
Mitosis: Cell begins to
divide.
Cytokinesis: The cell finishes
dividing and the cytoplasm
splits between them.
Mitosis
2.5.1Outline the stages in the
cell cycle
 Must
include
– Interphase (G1, S, G2)
– Mitosis
– Cytokinesis
2.5.1
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The first stage of cell division is interphase which
is divided into 3 phases; G1, S and G2. The cell
cycle starts with G1 (Gap phase 1) during which
the cell grows larger. This is followed by phase S
(synthesis) during which the genome is
replicated. Finally, G2 (gap phase 2) is the
second growth phase which separates the newly
replicated genome and marks the end of
interphase.
2.5.1
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The fourth stage is mitosis which is divided into
prophase, metaphase, anaphase and telophase.
During mitosis the spindle fibers attach to the
chromosomes and pull sister chromatids apart.
This stage separates the two daughter genomes.
Finally, cytokinesis is the last stage during which
the cytoplasm divides to create two daughter
cells. In animal cells the cell is pinched in two
while plant cells form a plate between the
dividing cells.
2.5.2 State that tumours (cancers) are the
result of uncontrolled cell division and
that these can occur in any organ or
tissue.
 Tumors
are formed when cell division
goes wrong and is no longer
controlled. This can happen in any
organ or tissue.
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2.5.3 State that interphase is an active
period in the life of a cell when many
metabolic reactions occur, including
protein synthesis, DNA replication and
an increase in the number of
mitochondria and/or chloroplasts.
Interphase continued…
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Phases of Interphase
– G1 = growth of cell, protein synthesis
– S = replication of DNA
– G2 = growth of cell, increase in
organelles, preparation for cell division.
2.5.4 Describe the events that occur in the four
phases of mitosis…
Prophase
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the mitotic spindle (made
from microtubules) starts
growing (going from pole
to pole).
Chromatin coils up to form
distinct chromosomes.
(Each chromosome
contains two identical sister
chromatids, attached to
each other at the
centromere region.)
The nuclear envelope starts
breaks down.
…Describe the events that occur in the
four phases of mitosis…
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each chromosome
attaches to two spindle
microtubules (one going
to each pole) at the
centromere.
line up at the equator
mitotic spindle is fully
developed
some microtubules are
attached to
chromosomes and reach
to the equator; others go
from pole to pole.
…Describe the events that occur in the
four phases of mitosis…
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Anaphase
– the spindle
microtubules
pull the sister
chromatids to
opposite poles
– each sister
chromatid
becomes one
new
chromosome
of the daughter
cell.

Telophase
– each sister chromatid reaches its pole (becoming a
chromosome).
– nuclear envelope starts to reform. Spindle microtubles
deteriorate.
Cytokinesis (division of the cytoplasm) takes place.
Summary of
Mitosis
Summary of mitosis continued
2.5.5 Explain how mitosis produces two genetically
identical nuclei. (an IB standard)
Mitosis is divided into four stages; prophase, metaphase, anaphase
and telophase. During prophase, the chromosomes become visible
under a light microscope as they super coil and therefore they get
shorter and more bulky. The nuclear envelope disintegrates and
the spindle microtubules grow and extend from each pole to the
equator. At metaphase the chromatids move to the equator. The
sister chromatids are two DNA molecules formed by DNA
replication and are therefore identical. These sister chromatids are
then separated in anaphase as the spindle microtubules attaches
to centromere and pulls the sister chromatids to opposite poles.
As the sister chromatids separate they are called chromosomes.
This means that each pole has the same chromosomes (same
genetic material). Finally the microtubules break down, the
chromosomes uncoil and the nuclear membrane reforms. The cell
then divides into two daughter cells with genetically identical
nuclei.

2.5.6 State that growth, embryonic
development, tissue repair, and
asexual reproduction involve mitosis.

Greater Tracy Area

Outline the differences in
mitosis and cytokinesis
between animal and plant
cells.
(limit this to the lack of the
centrioles in plant cells and the
formation of the cell wall.)


Animals:
– Centrioles
– No cell wall
Plants:
– No centrioles
– Cell wall (cell plate) is
formed between cells as
vesicles transport cell wall
materials to middle.







State that tumors are the
result of uncontrolled cell
division and that these
can occur in any organ.
Cancer cells do not respond
to cell cycle regulation
Transformation– results from
successive mutations
– mutagens
Tumor: benign (don’t
spread) or malignant (do
spread)
– Clonal
Metastasis – spreading of
cancer cells to other areas
http://www.pbs.org/wgbh/nova/cancer/ (Cancer Warrior–
angiogenesis resources)
http://www.pbs.org/wgbh/nova/cancer/progra
m.html (Video: Cancer Warrior-- angiogenesis)

http://www.pbs.org/wgbh/nova/cancer/grows.html
End of IB stuff


State that a virus is
a non-cellular
structure consisting
of DNA or RNA
surrounded by a
protein coat.
Characteristics of
Viruses
– not considered living
– no metabolism.
– Unable to reproduce
without a host
– Others?

Explain three
advantages of
using light
microscopes.
– color instead of
monochrome (black
and white) images.
– large field of view.
– Facilitate preparation
of sample material.
– Allow for the
examination of living
material and the
observation of
movement.
– Relatively
inexpensive

Outline the advantages of using
electron microscopes.
1) higher resolution and magnification than light microscopes.
– Resolution refers to the ability to distinguish two objects
as seperate entities.
– Magnification refers to the ability to increase the size of
a viewed object.
2) May provide a three dimensional view.
 Scanning Electron Microscopes (SEM) provide images of the
specimen's surface
 Transmission Electron Microscopes (TEM) provide images of
a sample's interior. The resolution of an SEM is
approximately half that of a TEM.
TEM
SEM