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Cells
Bell Ringer
1. What did Robert Hooke observe with the use of
a microscope? How did he describe what he
saw?
2. What 3 components make up the cell theory?
3. Where is the DNA housed in a eukaryotic cell?
4. How do organelles in a cell compare to organs
in the human body?
Learning Target
• “I can” analyze the difference between a
prokaryotic cell and a eukaryotic cell.
• “I can” analyze the difference between a plant
cell and an animal cell.
It’s a Rap
• http://www.youtube.com/watch?v=zafJKbMPA8
Discovery of the Cells
• The discovery of the cell helped answer this
question…
▫ How do living things differ from non-living
things?
• Microscopes have made a huge impact on the
study of biology.
▫ Microscope observations of organisms led to the
discovery of the basic characteristics common to
all living things.
History
• 1665, Robert Hooke observed a piece of cork
under a microscope that only had the strength to
magnify a specimen 30x.
▫ Hooke observed many little boxes in the cork.
• They reminded Hooke of small rooms that
monks live in called “cells.”
• Later, Hooke observed the same “little boxes” in
the stem and roots of plants.
History Cont.
• 10 years later a Dutch man by the name of Anton
Van Leeuwenhoek used a more powerful
microscope that could magnify specimens 300x.
▫ He observed pond water and discovered many
living creatures in the water that he named
animalcules, which means “tiny animals.”
• Thanks to Leeuwenhoek we now know these
animalcules as single celled organisms
(prokaryotes.)
History Cont.
• It took over 150 years for scientists to fully
appreciate the studies of Hooke and
Leeuwenhoek.
• Matthias Schleiden a German botanist,
concluded that cells make up every part of a
plant.
• 1 year later Theodore Schwan a German
zoologist, discovered that animals are also made
up of cells.
History Cont.
• Rudolph Virchow, a German physician,
proposed that cells only come from the division
of other cells.
• All of the observations form Schleiden, Schwan,
and Virchow helped form the Cell Theory.
Cell Theory
• The cell theory is composed of the following 3
things.
▫ 1. All living things are made up of one or more
cells.
▫ 2. Cells are the basic units of structure and
function in an organism.
▫ 3. All cells arise from existing cells.
Cell Shape
• Cells vary greatly in size and shape.
• A cells shape reflects the cells function.
▫ There are at least 200 types of cells.
▫ The human body is made up of about 100 trillion
cells.
• Larger cells often have shapes that increase the
surface area available for exchange.
Cell Size
• All substances that enter or leave a cell must
pass through the surface of a cell.
• As a cell gets larger, it takes up more nutrients
and releases more waste.
• Cell size is limited to by a cells surface areato-volume ratio.
• Cells with a greater surface area-to-volume ratio
can exchange substances more efficiently.
▫ Ex: lungs
Cell Organelles
• Cell Membrane- is the cells outer boundary.
▫ It acts as a barrier between the outside environment
and the inside of the cell.
• Cytoplasm- includes cytosol and almost all of the
structures that are suspended in it.
▫ Jelly like substance that is found in the inside of the
cell.
• Ribosome- is a cellular structure on which proteins
are made.
▫ Ribosomes are found all throughout the cytoplasm.
Prokaryotic Cell
• Prokaryote is a single celled organism.
▫ Ex: bacteria
• Organization is very simple. DNA freely floats in the
middle of the cell instead of being trapped in the
nucleus.
▫ Pro-No
• The prokaryotic cell wall surrounds the cell membrane.
The cell wall provides strength and structure to the cell.
• Capsule- is a structure around the cell wall that enables
prokaryotes to cling to surfaces, including, teeth, skin,
and food.
• Prokaryotic cells are thought to be 3.5 billion years
old.
Prokaryotic Cell
• Prokaryotic cells move around with the help of a
flagella.
▫ Flagella- Flagella are long projections composed
of protein. They rotate due to a protein motor
secured in the plasma membrane.
• Prokaryotic cells also contain pili.
▫ Pili- help bacteria stick to other cells. They are
short “hair like” projections.
Eukaryotic Cell
• Eukaryote is an organism made up of one or
more cells.
▫ Some live as single celled organisms.
▫ Others are multicellular.
• Because of their complex organization,
eukaryotic cells can carry out more specialized
functions that prokaryotic cells can not.
• Eukaryotic cells first appeared 1.5 billion years
ago
Eukaryotic
• Eukaryotic cells contain an organelle called a
nucleus that houses the DNA for the cell.
• Eukaryotes have membrane bounded organelles.
▫ Organelle- is a structure that carries out specific
activities inside the cell.
 Each organelle performs a distinct function.
• Eukaryotic cells contain, cytoplasm, ribosomes,
cell membrane, mitochondrion, Golgi apparatus,
endoplasmic reticulum, centrioles, Lysosomes,
nucleolus, and a nucleus.
Bell Ringer
Prokaryotic vs. Eukaryotic
• Compare and contrast a Eukaryotic and a
Prokaryotic cell.
Bell Ringer
• What 2 organelles prepare proteins for
extracellular transport?
• What is a central vacuole and where can it be
found?
• In the muscles there are tons of mitochondria,
why is this?
Framework of the Cell
• The cytoplasm of a Eukaryotic cell is packed
with structures particular to the cell.
• Cytoskeleton- helps the cell move, keep its
shape, and organize its parts.
▫ The cytoskeleton to the cell are like the bones to
the body.
3 types of Cytoskeleton
• 1. Microfilaments- are long, thin fibers that are
made of the protein actin.
▫ They contract to pull the membrane in some places
and expand to push it out in others.
• 2. Microtubules- are, thick hollow fibers that are
made of the protein tubulin.
▫ Information molecules travel through these tubes to
various places in the cell.
• 3. Intermediate Fibers- are moderately thick and
anchor organelles and enzymes to certain parts of
the cell.
Directing Cellular Activity
• Cellular activity depends on the proteins that the
cell makes.
• Instruction for making proteins is stored in the
DNA.
• In a Eukaryotic cell, DNA is packed into the
nucleus.
▫ This protects the DNA from other activity in the
cell from getting lost or destroyed.
Directing Cellular Activity
• DNA Instructions are copied as RNA messages,
which leave the nucleus  in the cytoplasm
ribosomes use the RNA messages to assemble
proteins.
Nucleus
• The nucleus is surrounded by a double
membrane called the nuclear envelope.
• The nuclear envelope has many nuclear pores.
▫ Nuclear pores- are small channels that allow
certain molecules to move in and out of the
nucleus.
• Nucleolus- located inside of the nucleus, this is
where the ribosome parts are made.
▫ Nucleolus nuclear pore cytoplasm
Ribosome.
Ribosome
• Ribosomes are made of RNA and many proteins.
• Free Ribosomes- Float freely in the
cytoplasm.
▫ Their job is to make proteins that remain inside
the cell, such as proteins that build new organelles
or enzymes to speed up reactions.
• Bound Ribosomes- are attached to the
membrane of another organelle.
▫ Their job is to make proteins that are exported
from the cell.
Protein Processing
• The proteins produced by cells have many uses.
• Proteins that are sent outside the cell must remain
separate from the cytoplasm. The cell does this with
the help of a vesicle.
▫ Vesicle- this is the site where proteins are packaged. It
is a small, often spherical shaped sac that is formed by
a membrane.
• In a eukaryotic cell 2 organelles are responsible for
modifying, packaging, and transporting proteins.
▫ The Endoplasmic Reticulum and The Golgi Apparatus.
Endoplasmic Reticulum
• Endoplasmic Reticulum (ER)- is a system of
internal membranes that moves proteins and
other substances through the cell.
▫ The ER is connected to the outer membrane of the
nuclear envelope.
Two Types of ER
• Rough ER- ribosomes are attached to the surface
of the ER.
▫ Rough ER has a bumpy appearance.
▫ 1.As proteins are made they cross the ER membrane,
entering the ER. Then, the ER membrane pinches off
to form vesicles around the protein.
• Smooth ER- the rest of the ER is called smooth
ER, with no attached ribosomes.
▫ Smooth ER has a smooth appearance.
▫ Smooth ER performs various functions such as making
lipids and breaking down toxic substances.
Golgi Apparatus
• Golgi Apparatus- is a set of flattened membranebound sacs.
▫ Cell products enter one side of the Golgi Apparatus,
which modifies, packs, and sorts them for distribution.
• 2. Repackaging-The vesicles membrane fuses with
the Golgi membrane. Inside the Golgi apparatus,
enzymes modify the protein as they move through
the organelle.
• 3. As the vesicle membrane fused with the cell
membrane, the completed proteins are released to
the outside of the cell.
Storage and Maintenance
• Vesicles play many roles in the cell.
▫ Vesicles- help maintain homeostasis by storing
and releasing various substances as cells need
them.
• Lysosome- is a vesicle that contains specific
enzymes that break down large molecules.
▫ These enzymes can digest food particles to provide
nutrients for the cell.
▫ They also help recycle materials in the cell by
digesting old, damaged, or unused organelles.
Lysosomes
• Lysosomes made by the Golgi Apparatus,
prevent the enzyme from destroying the cell.
Central Vacuole
• Central Vacuole- large membrane bound
compartment found in plant cells.
▫ Stores water, ions, nutrients and wastes.
▫ It can also store toxins and pigments.
• When the central vacuole fills up with water, it
makes the cell rigid, allowing the plant to stand
up right.
• When the central vacuole loses water it causes it
to wilt and the cell shrinks.
Other Vacuoles
• Contractile Vacuole- Pumps excess water out
of the cell.
▫ This process controls the concentration of salts
and other molecules and helps the cell maintain
homeostasis.
• Food Vacuole- forms when the cell membrane
surrounds food particles outside the cell and
pinches off to form a vesicle inside the cell.
Energy Production
• Cells need a constant source of energy.
• The energy needed for cellular function is
produced by chemical reactions that occur in the
mitochondria and chloroplasts.
▫ Eukaryotic cells= mitochondria
▫ Plant cells= chloroplasts
• In both reactions ATP is produced.
▫ ATP is the form of energy that fuels almost all cell
processes.
Chloroplasts
• Chloroplast- is an organelle that uses light
energy to make sugar from carbon dioxide and
water.
▫ In the inner membranes of the chloroplasts is
where the ATP producing chemical reactions take
place.
Mitochondria
• Mitochondrion- an organelle that uses energy
from organic compounds to make ATP.
▫ Cells that have a high energy requirement, such as
muscle cells, will contain more mitochondria.
▫ ATP producing enzymes are located on the inner
membranes of the mitochondria.
Word Bank
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Cell Membrane
Cytoplasm
Ribosome
Nucleus
Nuclear envelope
Rough ER
Smooth ER
Golgi Apparatus
Chloroplasts
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Flagella
Pili
Capsule
Mitochondrion
Cell wall
Lysosome
Vacuole
DNA
Bell Ringer
1. I am like the assembly line for the cell because
I assemble items that the cell needs
2. I am like the bricks for the cell because I give it
structure
3. I am like the control center for the cell because
I hold on the instructions of life
4. I am like the storage unit for the cell because I
stored materials until they are needed
5. I am like a bakery for the cell because I only
make proteins
Bell Ringer
1. An army is like a __________ because it
protects the U.S.A from its enemies.
2. A light bulb is like a ________because it gives
us energy.
3. A coach is like a _________ because he makes
all the decisions for the team.
4. A postman is like a ______ because he sorts
and packages items for people.
PLANT VS. ANIMAL
• If a scientist viewed a plant cell and an animal cell under a
microscope what could he or she expect to see?
• On the poster that I pass out you need to list, define and tell how
that particular organelle helps the cell function.
Bell Ringer
• Get out your notebooks and study what we have
covered so far in class.
• If you weren’t here Thursday you need to have
your project out on your desk and your
questions that you completed in your notebook
out.
Word Bank
• Nucleus
• Ribosomes
• Endoplasmic
Reticulum
• Cell Membrane
• Cell Wall
• Lysosome
• Vesicle
• Cytoplasm
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Golgi Apparatus
Nucleolus
DNA
Mitochondria
Chloroplasts
Nuclear Envelope
Vacuole
Diversity in Cells
• Prokaryotic cells are always unicellular and
limited in size.
• Eukaryotes are often larger and can be either
unicellular or multicellular.
• Prokaryotic cells lack a nucleus and membrane
bound organelles.
▫ The different organelles and features of cells
enable organisms to function in unique ways in
different environments.
Diversity in Prokaryotes
• Prokaryotes can vary in shape, the way that
they obtain and use energy, the makeup of their
cell walls, and their ability to move.
• Prokaryotes contain
▫ Flagella- long tail like structure that grows out of
the cell, allows the cell to move.
▫ Pili- are short hair-like projections that allow
prokaryotes to attach to surfaces or to other cells.
Types of cells
• The two types of Eukaryotic Cells are
▫ Animal and Plant
• Plant cells contain both cell walls and
chloroplasts which Animal cells do not.
• Plant and animal cells have highly specialized
cells that form tissues and organs.
▫ Tissue- a group of similar cells that perform the
same function
 Lung tissue
 Leaf tissue
Types of cells
• Organ- a collection of tissues that carry out a
specialized function in the body.
▫ Leaf
▫ Lung
• Organ System- a group of organs that work
together to form body functions.
▫ Circulatory System
▫ Root System
Body Types
• Multicellular Organisms- are composed of many
individual, permanently associated cells that
coordinate their activities.
• Colonial Organisms- a collection of genetically
identical cells that are permanently associated
but in which little or no integration of cell
activities occur.
Multicellularity
• True multicellularity occurs in eukaryotes.
• Multicellular organisms begin as a single cells.
▫ For example a chicken develops from an egg, new
cells form by cell division.
• Differentiation- is the process by which cells
develop specialized forms and functions.
BILL NYE
• http://www.youtube.com/watch?v=X6N82No4
Nz8
LINCS chart words
1.
2.
3.
4.
5.
Cell Membrane
Diffusion
Osmosis
Facilitated Diffusion
Dynamic
Equilibrium
6. Hypotonic
7. Hypertonic
8. Isotonic
9. Active Transport
10. Pumps
11. Exocytosis
12. Endocytosis