The Cell Theory
• The cell is the basic unit of structure and
function (life)
• All living things are made up of 1 or more cells
• Cells come from other, preexisting cells (
reproduction)
What is a cell?
• It is the smallest unit of life that
carries out life functions
Animal Cell
Plant Cell
What’s Inside?
• Organelles
– tiny structures within a cell that perform
specific jobs to keep the cell alive
Cytoplasm - gel-like material inside cells
Cytoplasm
Cell Membrane - protects cell and gives it shape
and controls what enters and leaves the cell.
Cell
Membrane
Nucleus - directs cell activities (brain)
Nucleus
Endoplasmic Reticulum (ER) - movement of
materials throughout cell
ER
Ribosome - makes proteins
Ribosomes
Mitochondria - the powerhouse of the cell
(converts food into energy for the cell)
Mitochondria
Chromatin/Chromosomes (DNA) - contains
genetic information (inside the nucleus)
Chromatin
Chloroplast - takes energy from the sun and
makes food for the PLANT cell (not found in
Animal Cells)
Chloroplast
Cell Wall - supports and protects PLANT cells
(not found in animal cells)
Cell Wall
Vacuole - storage of food and water
Vacuole
Golgi Body - packages and moves proteins
Golgi
Body
Lysosome - digests wastes
Lysosome
RNA and DNA
• RNA- ribonucleic acid, a molecule that is
present in all living cells and that plays a role
in protein production
• DNA- deoxyribonucleic acid, a molecule that is
present in all living cells and that contains the
information that determines the traits that a
living thing inherits and needs to live
Protein
• Protein- a molecule that is made up of amino
acids and that is needed to build and repair
body structures and to regulate processes in
the body.
• Amino Acids- are used in every cell of your
body to build the proteins you need to
survive.
Cells
Bill Nye- Cells
Cell- is a membrane- covered structure that
contains all of the materials necessary for life.
Cells are very small and because of their size,
they were not discovered until microscopes
were invented in the mid- 1600s
Cells
Robert Hooke was the first person to describe
cells. In 1665 he built a microscope to look at
tiny objects.
He looked at a thin slice of cork. The cork looked
like it was made of little boxes. Hooke named
these boxes cells, which means little rooms.
Cells
Robert Brown discovers the nucleus in a plant
cell
Matthias Schleiden discovers that all plat tissue
is made up of cells
Theodor Schwann shows that all animal tissue is
made up of cells
Cells
• Rudolf Virchow determines that all cells are
produced from cells.
• Parts of an animal cell- video
• What's in a nucleus- video
Two Kinds of cells
Prokaryote- a single-celled organism that does
not have a nucleus or membrane-bound
organelles; examples are archaea and bacteria
Eukaryote- an organism made up of cells that
have a nucleus enclosed by a membrane;
eukaryotes include protists, animals, plants and
fungi, but not archaea or bacteria
Organization of Living Things
YOU are a multicellular organism. That means
that you are made of many cells. Multicellular
organisms grow by making more small cells, not
by making their cells larger.
Benefits of Being Multicellular
• Larger Size- many multicellular organisms are
small. But they are usually larger than singlecelled organisms. Larger organisms are prey
for fewer predators. Larger predators can eat
a wider variety of prey.
• Longer Life- The life span of a multicellular
organism is not limited to the life span of any
single cell.
Benefits of Being Multicellular
• Specialization- Each type of cell has a
particular job. Specialization makes the
organism more efficient. For example, the
cardiac muscle cell is a specialized muscle cell.
Heart muscle cells contract and make the
heart pump blood.
• Specialized cells and tissues (video)
Misconception Alert
Dead Cells- Hair and fingernails are not living.
Hair and fingernails grow out of specialized skin
cells. They grow continuously, but both are
composed of dead cells and protein called
keratin. If hair and fingernails were alive and
contained nerve cells as the deep skin layers do,
haircuts and manicures would be painful!!!
Levels of organization in the body
Levels of Organization
Level 1:
Level 2:
Level 3:
Level 4:
Level 5:
Cell
Tissue
Organ
Organ System
Organism
Cell Size
Most cells are too small to be seen without a
microscope. However, a few cells are big. The
yolk of a chicken egg is one big cell. The egg can
be this large because it does not need to take in
more nutrients.
Cell Rap
Cell Size
There is a physical reason why most cells are so
small. Cells take in food and get rid of wastes
through their outer surface. As a cell gets larger,
it needs more food and produces more waste.
Therefore, more materials pass through its outer
surface.
A cell’s surface area-to-volume ratio limits the
size of a cell.
Cells Working Together
A TISSUE is a group of cells that work together
to perform a specific job.
Animals have 4 basic types of tissue: nerve
tissue, muscle tissue, connective tissue, and
protective tissue.
Levels of Organization
Cells Working Together
Epithelial Tissue
Epithelial Tissue: covers the body surface and
forms the lining for most internal cavities.
Major functions include protection, secretion,
absorption, and filtration. The skin is an organ
made up of epithelial tissue which protects the
body from dirt, dust, bacteria and other
microbes that may be harmful.
Connective Tissue
Connective Tissue: is the most abundant of the
tissues. Connective tissues perform a variety of
functions including support and protection. The
following connective tissues are found in the
human body- loose connective tissue, fat tissue,
dense fibrous tissue, cartilage, bone, blood, and
lymph.
Muscle Tissue
There are 3 types of Muscle Tissue: skeletal,
smooth, and cardiac. Skeletal muscle is a
voluntary type of muscle tissue that is used in
the contraction of skeletal parts. Smooth
muscle is found in the walls of internal organs
and blood vessels- it is involuntary. The cardiac
muscle is found only in the walls of the heart
and is involuntary.
Nerve Tissue
Nerve Tissue: composed of specialized cells
which not only receive stimuli (signals), but also
conduct impulses to and from all the parts of
the body. Nerve cells or neurons are long and
string like.
Cells Working Together
Plants have 3 types of tissues: transport tissue,
protective tissue and ground tissue
Transport tissue moves water and nutrients
through a plant. Protective tissue covers the
plant. It helps the plant retain water and
protects against damage. Photosynthesis takes
place in ground tissue.
Tissues Working Together
A structure that is made up of two or more
tissues working together to perform a specific
function is called an organ.
Plants also have different kinds of tissues that
work together as organs. A leaf, stem and roots
are examples of plant organs.
Organs Working Together
A group of organs working together to perform a
particular function is called an organ system.
Each organ has a specific job to do in the body.
Plants also have organ systems- leaf systems,
root systems and stem systems.
Organisms
Anything that can perform life processes by
itself is an organism.
Structure- is the arrangement of parts in an
organism. It includes the shape of a part and
the material of which the part is made.
Function- is the job the part does
Plant Organs
Prokaryotic Vs. Eukaryotic
Create a t-chart and fill in the information
towards the end of this video.
Prokaryotic vs Eukaryotic cells
Critical Thinking
1. Explain how the structure and function of an
organism’s parts are related. Give an
example.
2. What would happen if all of the ribosomes in
your cells disappeared?
3. Name two functions of the cell membrane.
Cell Structure and Function
Comparing organelles to school
Comparing organelles to school
Organelle
Part of School
Plasma (cell) membrane
Security System
Nucleus
Principal
Nucleolus
Cafeteria
Smooth Endoplasmic Reticulum
Bus system
Cytoskeleton
Walls, ceiling and support beams
Rough Endoplasmic Reticulum
Classroom
Lysosomes
Custodian
Cytoplasm
School Floor
Golgi Apparatus
Senior Class
Centrioles
Graduation
Mitochondria
Generator
Cell Project Ideas
Cell Project Ideas
Creating a SUPER cell
Materials needed:
Science journal with organelle functions
Paper
Crayons/markers/colored pencils
Partner from table group
MITOSIS
Mitosis
Mitosis Brain Pop Video
Mitosis- Amoeba Sisters
Mitosis
Mitosis is the simple duplication of a cell and all
of its parts. It duplicates its DNA and the two
new cells (daughter cells) have the same pieces
and genetic code. Two identical copies come
from one original. Start with one; get two that
are the same.
Mitosis
There are five (5) basic phases in the life-cycle of
a cell
PMATI
PROPHASE - METAPHASE - ANAPHASE TELOPHASE - INTERPHASE
The Phases
The Phases
Prophase: A cell gets the idea that it is time to
divide. First, it has to get everything ready. You
need to duplicate DNA, get certain pieces in the
right position (centrioles), and generally prepare
the cell for the process of mitotic division.
The Phases
Metaphase: Now all of the pieces are aligning
themselves for the big split. The DNA lines up
along a central axis (middle) and the centrioles
send out specialized tubules that connect to the
DNA. The DNA (chromatin) has now condensed
into chromosomes. Two strands of a
chromosome are connected at the center with
something called a centromere. The tubules
actually connect to the centromere, not the
DNA.
Chromosome
The Phases
Anaphase: The separation begins. Half of the
chromosomes are pulled to one side of the cell;
half go the other way. When the chromosomes
get to the side of the cell, it's time to move on to
telophase.
The Phases
Telophase: Now the division is finishing up. This
is the time when the cell membrane closes in
and splits the cell into two pieces. You have two
separate cells each with half of the original DNA.
The Phases
Interphase: This is the normal state of a cell
(resting state). It's just going about its daily
business of surviving and making sure it has all
of the nutrients and energy it needs. It is also
getting ready for another division that will
happen one day.
Critical Thinking
1. What happens to your cells as you grow?
2. What is mitosis?
3. Name the phases of Mitosis.
Diffusion
• Particles travel from where they are
crowded to where they are less crowded.
This movement from areas of high
concentration (crowded) to areas of low
concentration (less crowded) is called
diffusion. Diffusion also happens within
and between living cells. Cells do not
need to use energy for diffusion.
Diffusion/Osmosis
The cells of organisms are surrounded by
and filled with fluids that are made mostly
of water. The diffusion of water through
cell membranes is so important to life
processes that it has been given a special
name—osmosis.
Diffusion/Osmosis
Moving Particles
Particles travel through channels by either
passive or active transport. The movement
of particles across a cell membrane
without the use of energy by the cell is
called passive transport (high to low
concentration). Diffusion and osmosis are
examples of passive transport.
Moving Particles
A process of transporting particles that requires
the cell to use energy is called active transport
(low to high concentration).
Diffusion/ Osmosis
• Amoeba Sisters- Osmosis and Diffusion
Endocytosis and Exocytosis
The active-transport process by which a cell
surrounds a large particle, and encloses the
particle in a vesicle to bring the particle into the
cell is called endocytosis. Vesicles are sacs
formed from pieces of cell membrane.
Endocytosis and Exocytosis
When large particles, such as wastes,
leave the cell, the cell uses an activetransport process called exocytosis.
Cell Energy
Why do you get hungry? Feeling hungry is your
body’s way of telling you that your cells need
energy.
Animal cells have different ways of getting
energy from food. One way, called cellular
respiration, uses oxygen to break down food.
Many cells can get energy without using oxygen
through a process called fermentation.
Amoeba Sisters- Cellular Respiration
Fermentation
Have you ever felt a burning sensation in your leg
muscles while you were running? When muscle cells
can’t get the oxygen needed for cellular respiration,
they use the process of fermentation to get energy.
One kind of fermentation happens in your muscles and
produces lactic acid. The buildup of lactic acid
contributes to muscle fatigue and causes a burning
sensation. This kind of fermentation also happens in
the muscle cells of other animals and in some fungi and
bacteria.
The Cell Cycle
As you grow, you pass through different stages
in life. Your cells also pass through different
stages in their life cycle. The life cycle of a cell is
called the cell cycle.
Amoeba Sisters- Eukaryotic and Prokaryotic
The Cell Cycle
The cell cycle begins when the cell is formed and
ends when the cell divides and forms new cells.
Before a cell divides, it must make a copy of its
DNA.
DNA is the hereditary material that controls all
cell activities, including the making of new cells.
The DNA of a cell is organized into structures
called chromosomes.
The Cell Cycle
Prokaryotic Cells- Cell division in bacteria is
called binary fission, which means “splitting into
two parts.” Binary fission results in two cells that
each contain one copy of the circle of DNA.
The Cell Cycle
Eukaryotic cells are more complex than
prokaryotic cells are. The chromosomes of
eukaryotic cells contain more DNA than those of
prokaryotic cells do.
Humans have 46 chromosomes.
Similar chromosomes are known as homologous
chromosomes
The Cell Cycle
The Cell Cycle
A cell produces more cells by first copying its DNA.
Eukaryotic cells produce more cells through the four
phases of mitosis.
Mitosis produces two cells that have the same number
of chromosomes as the parent cell.
At the end of mitosis, a cell divides the cytoplasm by
cytokinesis.
In plant cells, a cell plate forms between the two new
cells during cytokinesis.
Critical Thinking
1. Compare: Name two organelles of a plant
cell that are not found in an animal cell.
Describe the function of those organelles.
2. Explain: What would happen to an animal
cell if it had no lysosomes?
3. Apply: Which kind of cell in the human body
do you think would have more mitochondriaa muscle cell or a skin cell? Explain?
Critical Thinking
1. List: What are 3 benefits of being
multicellular?
2. Apply: Could an organism have organs but
no tissues? Explain.
3. Compare: How are structure and function
different?
4. Explain: What does “specialization of cells”
mean?