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Cells, Tissues, Organs and Organ Systems
by Sajid Khan
What is a Cell?
Cells are the smallest unit of living matter. All living things are made up of cells including
bacteria, insects, small mammal’s and humans. There are a lot of different cells. Cells contain
atoms which is matter, the basic building blocks of objects. (1, 3)
Organism
Bacteria
Insect
Small mammal
Human
Bacteria are tiny
organisms whose single
cells have neither a
membrane-bounded
nucleus nor other
membrane-bounded
organelles. These
organisms are very
successful. Did you
know all bacteria found
on the surface of our
planet weigh more than
any other species?
That's amazing.
An insect can have millions of cells.
Insects have basic organ systems
that help all insects live and
reproduce. An organ system is a
group of organs that work together to
complete a specific task.
A small mammal can
contain millions of cells.
Don’t let size fool you.
Cells are microscopic so
they can fit in almost
any small space! Small
mammals also contain a
specific array of organ
systems
including
respiratory, circulatory,
ect. Which also included
in human organ systems
as well.
There are eleven major
organ systems in the
human body. Humans
contain a skeletal organ
system,
reproductive,
and an excretory organ
system. Humans can
produce billions of new
cells each hour! We put
our organ systems to
work.
Diagram
Notes
How Cells, Tissues, and Organ Systems Work.
Certain cells perform certain functions. When two cells perform similar functions they are both
organized into tissues. For example: A tissue like a skin tissue contain a collection of cells that are
highly specialized and are designed to do their job by creating new cells and absorbing the
nutrients to keep the skin healthy. If the cells in our skin didn’t fight off infection we would die
due to the infection passing through our skin into our body. (1, 3, 5)
Part
Cells
Tissues
Organs
Organ Systems such
as Circulatory
Cells are all different.
Each cell has a job. For
example a red blood
cells job is to carry
oxygen to the rest of
the body.
Tissues like blood and
skin are collections of
cells working together
to keep life in motion.
Organs like the heart,
brain, liver, and skin are all
collections of tissues. The
tissue
contains
many
functions to keep the
organs alive. The organs
all work together to sustain
life and create and organ
system.
This group of organs
transport blood and the
nutrients in blood through
out the body. This group of
organs work together and
become an organ system.
Diagram
Notes
How do cells and organ systems work together to create an
organism?

An organism is a living thing that can react to certain things like light, glucose,
carbon dioxide, etc. reproduce, grow, and maintain homeostasis. An organism can be
a bacteria, protist, fungi, virus, animal, or plant.
 An organ system is a group of organs that work together and complete a particular
task such as the respiratory systems job is to carry oxygen to your lungs and other
parts of your body then dispose of carbon dioxide.
 A cell is the structural, functional, and biological unit of organisms. (1, 5, 6. 7, 8)
“When two or more similar cells join together we get a tissue.
Two or more similar tissue fuse to form a organ.
Different organs function together to make a organ system.“ (8)
This is a tree map
explaining the flow of
how cells and organ
systems contribute to
making an organism.
Plant and animal cells
Plant and animal cells both have some things in common such as a nucleus. Plant cells contain
unique organelles that use light and turn it into energy. This is called photosynthesis. Each tiny cell
organelle has a special job to do within the cell. (1, 4)
Cell
Animal
Plant
Diagram
Cell part
Function
Nucleus
Found in both cells, A nucleus controls activity and contains cell genes.
Mitochondria
Breaths glucose and oxygen within the cell. Only found in animal cells.
Cell
membrane
The outer part of the cell which gives the cell shape and controls the cells molecules as
there passed in and out of the cell. Found both in animal and plant cells.
Cytoplasm
Chemical reactions that are very essential in the certain area. Found in both plant and
animal cells.
Cell wall
Strengthens the cell in the plant. Is made from cellulose. Found in Plant cells.
Vacuole
Contains a liquid that is sugary called cell sap. Found in plant cells.
Chloroplast
Carries out photosynthesis, turning light into energy. Only found in plant cells.
Essential cell organelles
Cell organelles carry out important functions in plants and animal cells. The nucleus builds
new proteins including enzymes and also controls activity in the cell so nothing goes hay
wire. The nucleus also contains DNA, the material of inheritance and is able to produce
new daughter cells during cell division aka mitosis. Mitochondria breathes glucose and
oxygen releasing energy. (1, 5)
Cell organelles in plants and animals:
Organelle
Mitochondria
Chloroplast
Nucleus
Cell membrane
Found in both
plant and animal
cells, Mitochondria
breaths
glucose
and oxygen to
release
energy
along with Co2
and water.
Chloroplast is only
found in plant cells.
They are able to
combine
carbon
dioxide and water by
using the energy from
light.
By doing this
they release oxygen
and glucose.
A
cell’s
nucleus
contains
necessary
information or genes
so it’s able to produce
new
cells,
new
enzymes and new
proteins.
Humans
have over 30,000
genes.
Controls passage of
substances in and out
of a cell. Movement of
the molecules happen
by
active
uptake,
which is high activity
in
taking
up
molecules.
Diagram
Function
Specific cells in Humans and Animals
Cells are designed for specific functions in the human body and an animal body, which are very
much alike. Billions and billions of cells work together in our body to support their assigned life.
A red blood cell for example does not contain a nucleus so there is more room to transport more
oxygen to the rest of the body. A muscle cell may contain more mitochondria than normal cells
because it must produce more energy. (1, 2, 4)
Specific cells in animals:
Cell
Red blood cell
Nerve cell
Sperm cell
Muscle cells
Red blood cells
contain
no
nucleus and have
a larger surface
area. This allows
than to carry
more oxygen to
larger areas of
the body.
These
cells
carry
connections
through
out
our body
to
different nerve cells.
The can send out
impulses
to
other
nerve cells to send our
body
different
messages in a short
amount of time.
Sperm cells can swim
to their destination,
being the female egg,
using the tails and
streamlined head to
reach the female egg
and
deliver
fertilization.
Muscle cells are rich
in
mitochondria
allowing
them
to
produce
massive
amounts of energy by
taking in glucose and
oxygen and turning it
into energy. They
contract to make our
bodies move.
Diagram
Notes
Specific cells in Plants.
Like in animal cells, plant cells are also specifically designed to function along with their rolls and
produce life. Millions of cells work together to produce food for these green plants by taking light
and turning it into energy. A pollen cell, for example is like a male sperm cell compared to an
animal sperm cell. The pollen cell is transferred to the female carpel by insects therefore creating
new genetic information to create a new plant. (1, 8, 10)
Cell
Root hair cell
Xylem cells
Pollen cell
Stomata cell
Root hair cells
contain a large
surface area, just
like red blood cells.
They have this
large surface area
to take in more
minerals and water
to
create
photosynthesis for
a healthy plant.
Water is carried up
and down the plants
stem and through the
Xylem vessels. These
are long tubes that
reach from the roots to
the leaf. Water moves
in xylem cells.
Pollen cells are like
the male gametes and
are transferred to the
female
carpel
by
insects such as bees.
Each
pollen
cell
contains
genetic
information to create
a new specific plant.
These cells are located
on the underside of
leaves to exchange
water, carbon dioxide,
and
oxygen
when
photosynthesis
is
occurring in the plant.
Diagram
Notes
The size of cells in plants and animals
Cells in plants and animals come in all different sizes. We need a microscope to exam the
size of cells. Plant cells are much smaller than animal cells. Both plant and animal cells
split or divide before becoming to large. If cells didn’t split the surface area would become
too large and release oxygen and nutrients that could have been absorbed. (1, 10,11)
Cell
Typical animal cells
Typical plant cells
Cell division in plants and animals
Diagram
Notes
Mitosis
Animal cells range
much larger than
plant cells. They can
stretch to 10 to 100
meters.
Plant cells are
much smaller than
animal cells. Plant
cells stretch from
10
to
30
micrometers.
Stage one
2n
Parent cell
Stage two
4n
DNA replicates
Stage three
2n
Chromosomes
separate
Stage four
2n
2 Daughter cells
When cell volume increases, the ratio
decreases between surface area and
volume decreasing. This reduces the cells
ability to absorb nutrients and oxygen in the
cell membrane. Over a million cells split in
our bodies every day doubling our cells.
The Code For Life and Bio
Information
Organism
.
Tissues
Organ
System
Cell
Nucleus
The Code For Life
Chromosome
Big nose
Brown eyes
Nucleus
Straight hair
Genes
Structural Biology
Medicine and Biology at the Atomic Scale
Organ  Tissue  Cell  Molecule  Atoms
 A cell is an organization of millions of molecules
 Proper communication between these molecules is
essential to the normal functioning of the cell
 To understand communication between molecules:
*determine the arrangement of the atoms*
Advanced Cell &
Developmental Biology
Gene, Recombinant DNA
& Cloning Analysis
Restriction Enzymes
• Restriction enzymes are DNases
(nucleases) found in bacteria that recognize
specific DNA sequences as 4mers,6mers or
8mers and make double stranded breaks in
DNA .
• This enables cutting of genome in specific
ways to generate restriction site maps and
the development of approaches for pasting
pieces of DNA together in specific ways.
A
Separation
of EcoR1
B
segments
C
on an
D ,E agarose gel
F
DNA Hybridization
• DNA hybridization is the process whereby complementary strand of DNA anneals
(to form a double helix) with the single stranded DNA
• Hybridization can be measured by labeling the “complementary strand” either with
32P nucleotides or fluorescent probes .
• There is also DNA-RNA hybridization
Southern Blotting
• Southern Blotting enables identification of specific DNA sequences (gene
fragments) from among the total sequence of DNA
Cut DNA with restriction
enzymes
Separate fragments on
agarose or acrylamide
gels
Transfer the separated
DNA from gel on to
nitrocellulose paper
Hybridize with a labeled DNA or RNA of
interest ( e.g., 32P labeled DNA) followed
by autoradiography or phosphoimaging
for detection
Northern Blotting
•
Northern Blotting is where RNA is blotted and then probed labeled DNA (cDNA)
synthesized from the mRNA isolated from the cell
• Enables identification and quantification of specific mRNAs from among the vast
population of RNAs in the cell
DNA cloning
• DNA cloning enables specific
pieces of genome to be inserted
into bacteria as plasmid or
phage lambda vectors and
grown in large quantity.
• The first step is to generate a
library of bacteria with inserted
DNA fragments. This could
either be a genomic(DNA)or a
cDNA (mRNA) library
Replica plating and in situ hybridization
• Techniques used to identify a bacterial colony that contains the gene (DNA sequence)
of interest. The isolated colony can be grown up in large quantities.
CsCl centrifugation for separation of plamid DNA
from chromosomal DNA
Replica plating and in situ hybridization
cDNA libraries
• They are generated to isolate
particular genes of interest or to
identify a gene based on the protein
expression of that gene cloned in
the bacterial cell
• The latter procedure is called
“reverse genetics” whereby the
protein product is used to identify
the gene followed by DNA
sequencing
DNA sequencing
•
Sanger’s dideoxy method
DNA to be sequenced is
mixed with each of 4
ddNTPS (chain
terminators) in separate
reactions for DNA
synthesis and later
separation of the products
by electrophoresis
•
Can now be done
automatically via
sequencing machines that
work with different
flurochromes attached to
each of dideoxy
nucleotides
•
To determine the sequence
of a gene of many
kilobases overlapping
DNA fragments of 400800 bp must be sequenced
Protein expression vectors
• These are specially designed plasmid
vectors for fusion protein expression
to isolate large quantities of protein of
interest for antibody production or
other studies of purified protein.
• The proteins are produced as fusion
proteins of the cDNA gene coding
sequence ligated to a protein
expression marker or reporter protein
e.g. beta-galactosidase
• They can also be used as a major tool
in cell biology to study the expression
of proteins in cells following DNA
transfection
DNA transfection and Polymerase chain reaction (PCR)
• DNA transfection is used to
Polymerase chain reaction (PCR)
track the properties of individual proteins
in a cell
Is used as an alternative to cloning
for purifying a particular DNA (gene
sequence
Construct a plasmid expression system
that contains the protein of interest fused
with a reporter gene such as a betagalactosidase or a short peptide sequence
such as HA 9 mer peptide or FLAG
epitope for antibody localization with
anti HA or anti FLAG or fluorescent
localization in living cells with GFPconstructs (GFP-actin)
It enables the production of microgram
quantities of the DNA sequence of
interest in the test tube
Provides an alternative for preparing DNA
probes to screen genomic or cDNA library
for clones encoding a protein of interest
DNA Microarrays and chips
• Enable via fluorescence in situ hybridization (FISH) to measure expression
of 1000’s of genes on each array/ chip.
Actual chip size
Yeast genome microarray: The array is hybridized to cDNA
labeled with a green fluorescent dye prepared from cells grown in
glucose and with red labeled cDNA from cells grown in ethanol.
Spots were detected with a scanning confocal microscope
Antibody production
• Polyclonal antibodies are
generated by injecting
antigen into an animal and
purifying the antibody
titer from blood
• Monoclonal antibody
technique enables to obtain
a single clone of cells that
recognizes one epitope
( usually ~ 9 a.a.) of the
total protein
Monoclonal antibody production
Genetic Engineering
• Introduction of exogenous genes ( mutant or
normal) in to normal cells or organisms to study
gene expression
• Used to study the role of the protein coded by the
gene in the cell/organism function or for
engineering gene expression for improving food
production or reducing the destrcutive damage of
human diseases
Site Directed Mutagenesis
• Alterations in nucleotides (substitutions or
deletions) in vitro at known (directed) sites to
create “mutant genes”
• These mutant genes can be transfected into cells as
previously discussed and enables study of gene
function at the individual cell level. The
transfected genes are also called “transgenes”
Production of transgenic mouse
Inject mutant gene
in to one of the
pronuclei of the
fertilized mouse
oocyte
Transfer oocyte to
surrogate mother. 1030% of offspring
contain the transgene
in equal amounts in
all tissues
Gene Knockout or “replacement”
• Form of trangenics
• Occurs following homologous recombination of the transgene at the site of the
endogenous gene
• Occurs readily in yeast cells but in mammalian cells the rate of recombination is very
slow and hence a double selection marker approach is adopted where the first marker
e.g. neomycin resistance selects for all cells with homologous recombination while
the second marker allows growth of only those cells that carried out homologous
recombination
Knockout protocol
ES cells are isolated
from the inner
blastocyst and
culture
ES cells are
tranfected with
the gene of
interest
ES cells successfully
transfected via homologous
recombination are selected
and grown in culture and
injected into a host
blastocyst. Chimeras
develop which contain ES
cells from both the
transfected and the host
cells.
Enables
direct study of
gene function
in an intact
organism
Gene Replacement/therapy
• Replace an abnormal
gene with a normal one
at a very early stage of
development
• It has the potential for
curing or alleviating the
symptoms of a wide
variety of human
diseases, e.g.,Parkinson’s
disease
Procedure for gene replacement
How Ian Wilmut Made Dolly 1
Making Quiescent Cells
Mammary gland cells
Finn Dorset ewe
3.5 months pregnant
Culture mammary cells
Starve cells
Harvest quiescent
cells
How Ian Wilmut Made Dolly 2
Collecting The Donor Nucleus
Glass pipette
Suction
Suction
Pipette
How Ian Wilmut Made Dolly 2
Collecting The Donor Nucleus
Glass pipette
Suction
Suction
Pipette
How Ian Wilmut Made Dolly 3
Egg Preparation
Egg
Scottish Blackfaced
ewe egg donor
An egg is collected then
placed into a dish where it
can be manipulated
How Ian Wilmut Made Dolly 3
Egg Preparation
Glass pipette
Egg
Chromosomes
Suction
Suction
Pipette
How Ian Wilmut Made Dolly 3
Egg Preparation
Chromosomes
Glass pipette
Egg
Suction
Suction
Pipette
How Ian Wilmut Made Dolly 4
Inserting The Donor Nucleus
Glass pipette
Suction
Suction
Pipette
How Ian Wilmut Made Dolly 4
Inserting The Donor Nucleus
Glass pipette
Suction
Suction
Pipette
How Ian Wilmut Made Dolly 4
Inserting The Donor Nucleus
Suction
Suction
Pipette
How Ian Wilmut Made Dolly 5
Initiating Development
How Ian Wilmut Made Dolly 5
Zygote
Initiating Development
How Ian Wilmut Made Dolly 5
Cleavage
Initiating Development
How Ian Wilmut Made Dolly 5
Cleavage
Initiating Development
How Ian Wilmut Made Dolly 5
Cleavage
Initiating Development
How Ian Wilmut Made Dolly 5
Cleavage
Initiating Development
How Ian Wilmut Made Dolly 5
Morula
Initiating Development
How Ian Wilmut Made Dolly 6
Development
Morula
Scottish Blackfaced
ewe surrogate
mother
Finn Dorset lamb
Dolly
References
1. Unit 38 Cells, Tissues, and Organ Systems
http://www.slideshare.net/scienceinteractive/unit-38-cells-tissues-organs-and-organsystems
2. Medicene.Net
http://www.medterms.com/script/main/art.asp?articlekey=5260
3. Biology.about.com
http://biology.about.com/od/organsystems/a/aa031706a.htm
4. Cells Alive!
http://www.cellsalive.com/cells/3dcell.htm
5. Cells and Organelles
http://biology.clc.uc.edu/courses/bio104/cells.htm
6. Answers.com
http://www.answers.com/topic/organism
7. Biology-online.org
http://www.biology-online.org/dictionary/Cell
8. Biology-online.org
http://www.biology-online.org/dictionary/Cell
9. Wiki.answers.com
http://wiki.answers.com/Q/Relate_cells_to_tissues_to_organs_to_organ_systems_how_
do_they_work_together
References
10. Microscopy.fsu.edu
http://www.microscopy.fsu.edu/cells/plantcell.html
11. Wikipedia.org
http://en.wikipedia.org/wiki/Cell_%28biology%29