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Cell Structure
Standard 7.L.3 The student will demonstrate an
understanding of how the levels of organization within
organisms support the essential functions of life.
Lesson Standard
7.L.3A.1 Obtain and communicate information to
support claims that (1) organisms are made of one
or more cells, (2) cells are the basic unit of
structure and function of organisms, and (3) cells
come only from existing cells
The History of Viewing Cells
●
The first microscope was made in the
late 1500’s. It was two magnifying
glasses put together in a tube.
●
Antonie van Leeuwenhoek made a
simple microscope with a tiny glass
bead for a lens.
●
THINK ABOUT IT: What kind of
microscopes do we use in lab?
Development of the Cell Theory
Cell Theory: the summary of
ideas that says:
1) All organisms are made up
of one or more cells
2) The cell is the basic unit
of organization
3) All cells come from cells
that already exist
Development of the Cell Theory - Timeline
● 1665: Robert Hooke looked at a thin slice of cork
under a microscope. He saw tiny empty boxes,
which he named cells.
● 1830: Matthias Schleiden studied plants under a
microscope. He concluded that all plants are made
of cells.
Development of the Cell Theory - Timeline
● Theodor Schwann studied animals under a
microscope. He concluded that all animals are
made of cells.
● Schleiden and Schwann came to the conclusion that
all living things are made of cells.
● Rudolf Virchow made a hypothesis that cells divide
to form new cells. Cells come from a cell that
already existed.
Robert Hooke
Cells means “little rooms”
in Latin
Schleiden & Schwann
Plant cell
Animal cell
Rudolf Virchow
The Cell Theory
All organisms are made up of An organism can be one cell
one or more cells.
or many cells. Most plants
and animals have many cells.
The cell is the basic unit of
organization in organisms.
Even in a complex organisms,
the cell is the basic unit of
structure and function.
All cells come from cells.
Most cells can divide to form
two new cells that are
identical.
7.L.3A.3 Develop and use models to
explain how the relevant structures
within cells (including cytoplasm, cell
membrane, cell wall, nucleus,
mitochondria, chloroplasts, lysosomes,
and vacuoles) function to support the
life of plant, animal, and bacterial cells.
Cell structures / ORGANELLES
● Structures that are
common to plant and
animal cells are the
cell membrane,
nucleus, mitochondria,
and vacuoles.
● Structures that are
specific to plants are
the cell wall and
chloroplasts.
What is the function of a cell wall?
● Cell Walls: a tough, rigid
outer covering that
protects the cell and
gives it shape
● You find cell walls in the
cells of plants, algae,
fungi, and most bacteria
● Cellulose is a
carbohydrate that makes
up a plant cell wall
What is the function of a cell wall?
● Pectin may also be found in the cell
wall. It gives the cell wall strength and
helps it grow and develop.
● Lignin may also be found in the cell
wall. It is a compound that makes the
cell wall rigid.
● Where would you find plant cells with
high amounts of lignin?
Cytoplasm
● The gel-like fluid inside of a cell made of mostly
water. The other organelles are embedded in the
cytoplasm
● Made up of mostly water and salt
● Cytoplasm is responsible for giving a cell its
shape. It helps to fill out the cell and keeps
organelles in their place. Without cytoplasm, the
cell would be deflated and materials would not
be able to pass easily from one organelle to
another.
Nucleus
● Contains the genetic material (DNA)
and is the control center of the cell.
● One type of cellular reproduction,
mitosis, occurs in the nucleus. This
results in a duplicate copy of the cell.
● Mitosis is needed for:
● Growth - Ex: Babies grow into adults
● Repair - Ex: Repair a cut
● Replacement - Ex: Dead skin cells
need to be replaced
Vacuole
● Act as temporary storage
centers.
● Some store water; others
store waste products until
they can be eliminated from
the cell.
● Plant cells have fewer and
larger vacuoles than animal
cells.
Chloroplasts
● Are the sites where photosynthesis takes place in
a plant cell
● They contain the chlorophyll, the green pigment
that absorbs light energy
Chloroplasts
● During the process of photosynthesis, plants use
light energy (sunlight), carbon dioxide (CO2), and
water (H2O) to make glucose, a simple sugar
(C6H12O6) and oxygen gas (O2)
● Plant cells also release oxygen gas (O2) as a
waste product of photosynthesis
Mitochondria
● It is sometimes called the
“powerhouse” of the cell
● Are the energy producing sites
in the cell where respiration
takes place
● All organisms undergo cellular
respiration. During this process,
glucose (C6H12O6) is broken
down into carbon dioxide (CO2)
and water (H2O) to release
energy
Mitochondria
● The cell uses the energy to
build, repair, and
reproduce cells
● Cellular respiration is the
complementary process to
photosynthesis
● Cells that require a larger
amount of energy to
function contain a larger
number of mitochondria
Lysosomes
● Organelles responsible for digesting certain
materials within the cell
● The lysosome can digest food, worn out
organelles, as well as other cellular waste not
needed for cell metabolism
Only
found in
animal
cells
Cell membrane
● The thin,
flexible outer
covering of a
cell. It
controls what
enters and
leaves a cell
Two Main Ways Substances Enter and
Exit a Cell:
1. Diffusion is one way in which materials (for
example molecules of sugar, or waste) moves
across the cell membrane. It occurs as
materials move from an area of higher
concentration to an area of lower
concentration.
2. Osmosis is the diffusion of water across a
membrane.
Concentration gradient
Concentration Gradient - change in the concentration of a
substance from one area to another.
Diffusion
Molecules in solution tend to slowly spread
apart over time. This is diffusion.
Diffusion
●
Movement of molecules from an area of high concentration
to an area of lower concentration.
●
● Factors that affect the rate of diffusion: size of molecules,
size of pores in membrane, temperature, pressure, and
concentration.
Diffusion
concentrated, high energy molecules
[High]
[Low]
diffuse, low energy molecules
http://highered.mhe
ducation.com/sites/
0072495855/stude
nt_view0/chapter2/
animation__how_di
ffusion_works.html
Osmosis
● Osmosis is the movement of water across a
semi-permeable membrane
● At first the concentration of solute is very high on the
left.
● But over time, the water moves across the
semi-permeable membrane and dilutes the particles.
Osmosis – A Special kind of Diffusion
● Diffusion of water across a selectively permeable
membrane (a barrier that allows some
substances to pass but not others). The cell
membrane is such a barrier.
● Small molecules pass through – ex: water
● Large molecules cannot pass through – ex:
proteins and complex carbohydrates
http://highered.mhedu
cation.com/sites/0072
495855/student_view
0/chapter2/animation
__how_osmosis_wor
ks.html
PASSIVE TRANSPORT
● Passive transport occurs without expenditure of energy.
Molecules move using their own kinetic energy. Diffusion
and osmosis are examples of passive transport.
● Passive transport allows cells to get water, oxygen and
other small molecules that they need. It also allows the
cell to get rid of waste such as carbon dioxide.
OSMOSIS
DIFFUSION
7.L.3A.2 Analyze and interpret data
from observations to describe different
types of cells and classify cells as
plant, animal, protists, or bacteria
Unicellular or Multicellular
Organisms
● Unicellular organisms are
composed of one cell and
would include most protists
and bacteria.
● Multicellular organisms are
made up of lots of cells and
include plants & animals
Cellular Organization
Prokaryotic or Eukaryotic
● Prokaryotic cell: no membrane-bound
structures within the cell
● Lacks a nucleus
● Bacteria compose the majority of prokaryotic
organisms
● Eukaryotic cell: a cell with membrane-bound
structures
● Plant, animal, and protists are eukaryotic
Major structural differences between a
plant and an animal cell include:
● Plant cells are usually rectangular; animal
cells are usually round.
● Plant cells have a cell wall, but animal
cells do not. Cell walls provide support and
give shape to plants.
● Plant cells have chloroplasts, but animal
cells do not. Chloroplasts enable plants to
perform photosynthesis to make food.
Major structural differences between a
plant and an animal cell include:
● Plant cells usually have one large vacuole,
while animal cells have smaller vacuoles, if
any are present. Large vacuoles help
provide shape and allow the plant to store
water and food for future use. The storage
function plays a lesser role in animal cells,
therefore the vacuoles are smaller.
Classifying an organism as
photosynthetic or non-photosynthetic
● Cells that are photosynthetic contain
chloroplasts and the pigment chlorophyll.
This would include most cells of the plant
kingdom and some protist.
● Non-photosynthesizing cells would lack
chloroplasts and chlorophyll. This would
include cells of the animal kingdom.
7.L.3A.4 Construct scientific arguments
to support claims that bacteria are both
helpful and harmful to other organisms
and their environment.
Bacteria are classified by shape
Bacteria can be helpful to
organisms and the environment
● Bacteria are in our digestive system and aid in
breaking down and absorbing food.
● Bacteria are used to make a variety of foods
including cheese and yogurt.
● Bacteria can decompose dead organisms and
release those nutrients back into the
environment.
Bacteria can be harmful to
organisms and the environment
● Bacteria can be pathogens and cause diseases
like strep throat, food poisoning, and
tuberculosis.
● Bacteria, such as wheat blight can infect
plants that are used as crops.
● Other bacterial pathogens that could be
considered are tetanus, bacterial pneumonia,
and a variety of other infectious diseases that
can affect a variety of living organisms.
Helpful & Harmful bacteria
● Some bacteria can be classified as both helpful
and harmful depending on the location of
infection in the human body. For example, E.
coli bacteria naturally live in the human
intestine. E. coli is essential for digestion to
occur. However, if E. coli enters the stomach
through contaminated food, it can cause
foodborne illness.
7.L.3B.1 Develop and use models to
explain how the structural organizations
within multicellular organisms
function to serve the needs of the
organism.
https://www.youtube.com/watch?v=ZRFykdf4kDc
The levels of organization,
from the simplest level to the most complex are:
Cell - The basic units of structure and function
within all living things. Though all cells perform
the processes that keep the organism alive, they
also have specialized functions as well.
Examples may be nerve cells (neurons), blood
cells, and bone cells, in animals and guard cells,
xylem cells and phloem cells in plants
The levels of organization,
from the simplest level to the most complex are:
Tissue - A group of specialized cells that work
together to perform a specific function.
Examples of the main types of tissue in animals
are nervous tissue, connective tissue, muscle
tissue, and epithelial tissue. Plants contain
xylem and phloem tissue that is comprised of
xylem and phloem cells.
The levels of organization,
from the simplest level to the most complex are:
Organs - A group of two or more different types
of tissue that work together to perform a
specific function. The task is generally more
complex than that of the tissue.
For example, the heart is made of muscle and
connective tissues which function to pump blood
throughout an animal. Flowers, roots, and stems
are organs in plants.
The levels of organization,
from the simplest level to the most complex are:
Systems - A group of two or more organs that
work together to perform a specific function.
Each organ system has its own function but the
systems work together and depend on one
another. Plants and animals have a reproductive
system.
https://www.youtube.com/watch?v=nnjmrrQ6xOs
Types of Tissue
Nerve tissue: Carries impulses, or
signals, back and forth between the
brain and the body.
Muscle tissue: Contracts and shortens, making body parts move.
There are three types of muscle tissues. Cardiac, smooth and
skeletal.
Epithelial tissue: covers surfaces of the body. Inside the body,
epithelial tissue serves as a lining or covering for internal
organs. Forms a layer of skin outside the body.
Connective tissue: Connects all parts of the body and provides
support. Examples of connective tissue includes tendons,
ligaments and cartilage.
Types of Muscle Tissue
Smooth Muscle
● Occurs in walls of
internal organs
● Involuntary
Cardiac Muscle
● Only occurs in the
walls of the heart
● Involuntary
Skeletal Muscle
● Usually attached to
bone
● Voluntary
7.L.3B.2 Construct explanations for how
systems in the human body (including
circulatory, respiratory,
digestive, excretory, nervous, and
musculoskeletal systems) work together
to support the essential life functions
of the body.
Nervous System
What does the nervous system do for our bodies?
What organs make up the nervous system?
Nervous System
The main functions of
the nervous system
● To receive stimuli
from inside and
outside the body
● To interpret the
stimuli
● Initiate responses
for survival
Nervous System
The main organs of the nervous system are:
1. Brain
2. Spinal Cord
3. Peripheral Nerves
https://www.youtube.com/watch?
v=NALZwb-_YO4
● An organ which has three
distinct parts that all serve
to control and coordinate
the activities of the body.
● All the parts of the brain
work together, but each
part has its own special
properties.
● The brain is divided in half
into two hemispheres.
Brain
3 Main Areas of the Brain
● Cerebrum - largest part of the brain
○ Controls thoughts, voluntary actions,
& the sensations related to the 5 senses
● Cerebellum - small lobe located at the
back of the brain
○ Helps with balance and coordination
● Brain stem - (Also called the medulla) located at the
base of the brain
○ Controls vital and involuntary processes
(breathing, heartbeat, & digestion)
Spinal Cord
A bundle of nerves
that begins at the
brainstem and
continues down
the center of the
back through the
vertebrae. It
connects with the
peripheral nerves.
Peripheral Nerves
A network of
nerves that branch
out from the spinal
cord and connect
to the rest of the
body and transmit
signals to and from
the brain through
the spinal cord.
Circulatory System
What does the circulatory system do for our bodies?
What organs make up the circulatory system?
Functions of the Circulatory System
The main functions of the
circulatory system is to
transport blood to all parts of
the body so that gases,
nutrients, and waste products
are transported to and from
the cells.
The Main Organs
1) Heart - Causes blood to circulate through
the body by its pumping action
2) Blood Vessels (arteries, veins, &
capillaries) - tubes that carry blood
throughout the entire body.
http://www.youtube.com/watch?v=nOLFVC10ctw
Functions of the Circulatory System
● Transport gases- oxygen from the lungs to cells
around the body and carbon dioxide from the cells
to the lungs.
● Transport nutrients (sugars, calcium); Transport
wastes from cells to organs that are capable of
breaking wastes down (liver, kidneys)
● The white blood cells within the circulatory system
help to fight infection in the body.
● Maintains the pH levels and ionic concentration of
fluids in the body, and Helps maintain body
temperature
What are Arteries and Veins?
● Most arteries carry blood that has oxygen and
nutrients to all the parts of the body.
● Most veins carry waste products (for example
carbon dioxide) from all the parts of the body back
to the heart.
What are capillaries?
● Capillaries are very
small vessels where
the exchange of
oxygen and nutrients
from the blood into
the cells and carbon
dioxide & other waste
products enter the
blood from the cells.
The Heart
● Causes blood to circulate through the body by its
pumping action
● The heart is a hollow organ about the size of a clenched
fist. It is made almost entirely of muscle.
● As the heart pumps blood, it creates a pressurized system
that forces blood to travel through the blood vessels
throughout your body, and back to the heart again, thus
circulation!
● Your heart pumps more than 1600 gallons a day!
The Heart
The heart has two layers:
1. The outer layer of the heart is a protective film
called pericardium. (peri means outer)
2. The inner layer of
the heart is known as
myocardium.
(myo means muscle)
The Heart has Four Chambers
The Human heart has 4 chambers, as follows:
● the right ventricle
● the left ventricle
● the right atrium
● the left atrium.
Atria receive blood going into the heart.
Ventricles pump blood out of the heart.
Blood Flow
Blood enters the heart
through two large veins,
the inferior and superior
vena cava, emptying
oxygen-poor blood from
the body into the right
atrium of the heart. As
the atrium contracts,
blood flows from your
right atrium into your
right ventricle through
the open tricuspid valve.
https://www.youtube.com/watch?v=BE
WjOCVEN7M
Blood is composed of red blood cells, white blood
cells, platelets, and plasma. These components have
different functions.
Parts of the Blood:
● Red Blood Cells
○ Contain hemoglobin which is a protein that
helps carry oxygen and carbon dioxide
● White Blood Cells
○ Part of your immune system and help fight
infections
● Platelets
○ Help form clots to stop bleeding
● Plasma
○ Transports nutrients, hormones, and proteins
https://www.youtube.com/watch?v=R-sKZWqsUpw
Functions of Blood:
1. Transportation:
a. oxygen & carbon dioxide
b. nutrients
c. waste products (metabolic wastes, excessive
water, & ions)
2. Regulation - hormones & heat (to regulate body
temperature)
3. Protection - clotting mechanism protects
against blood loss & leukocytes provide
immunity against many disease-causing agents
Respiratory System
What does the respiratory system do for our bodies?
What organs make up the respiratory system?
Respiratory System
● The main function of the respiratory system is
to provide gas exchange between the blood
and the air.
● When air is inhaled, the lungs remove oxygen
from the air. Carbon dioxide is exhaled back
into the environment when it is removed from
cells and carried by the blood to the lungs.
● Enables speech production.
Respiratory System
The main organs of the
respiratory system are:
1) Nose-Collects air from
the environment. Moistens
and heats the air before it
enters the trachea.
2) Trachea-The
windpipe; moves air from
the nose to the lungs.
Respiratory System
3) Bronchi (e.g.
bronchus)-Tubes that
move air from the
trachea to the lungs; one
bronchus leads to each
lung; part of each
bronchus is outside the
lung and part is inside.
Respiratory System
4) Lungs-The main organs
where gases are
exchanged between air
and the blood; the alveoli
are small sacs within lung
tissue. It is in the alveoli
where the gas exchange
takes place.
https://www.youtube.com/
watch?v=AJpur6XUiq4
Respiratory System
5) Diaphragm The muscle that
aids in the
breathing
process and
allows the rib
cage to expand
https://www.youtube.co
m/watch?v=hp-gCvW8
PRY
Digestive System
What does the digestive system do for our bodies?
What organs make up the digestive system?
Digestive System
The main functions of the
digestive system are:
● To break down foods
into nutrients that can
be used by the body
● Absorb nutrients that
are necessary for
energy, growth, and
maintenance
● Rid the body of solid
wastes.
Digestive System
● The organs of the digestive system can be divided
into two categories, primary and secondary.
● Primary organs have a direct role in digesting
food and come into physical contact with the
food
● Secondary organs support the process of
digestion by secreting digestive juices. Food
does not pass through secondary organs
Elbow Partner
Discuss the difference between primary organs and
secondary organs of the digestive system.
Primary Organs
● Mouth
● Begins to break down food into smaller pieces
through mechanical digestion; saliva in the
mouth starts the process of chemical digestion
● Esophagus
● Tube that carries chewed food to the stomach
● Peristalsis is the muscle movement that pushes
food to the stomach
● Stomach
● Continues the process of mechanical digestion;
secretes gastric juices that continue the process
of chemical digestion started in the mouth
Primary Organs
● Small Intestines
● The organ where most of the
chemical digestion of food takes
place; nutrients from food are also
absorbed into the bloodstream
through the small intestines
● Large Intestines
● The organ where water from the
food is absorbed into the
bloodstream; prepares the
remaining undigested food for
elimination from the body
Primary Organs
● Rectum
● A short tube that stores solid waste until it
is eliminated from the body
● Anus
● Opening where solid waste is eliminated
Secondary Organs
● Liver
● Produces bile, which is used by
the body to break up fat, and
filters blood
● Gallbladder
● Stores bile produced by the liver
● Pancreas
● Produces digestive juices that
help to further break down the
food in the small intestine
Types of Digestion
● Mechanical digestion involves physically breaking
the food into smaller pieces
● Begins in the mouth as the food is masticated
● Masticate is a synonym for chew
● Also occurs in the stomach from the churning
that mixes the food with stomach acids
Chewing + Churning = Mechanical
Types of Digestion
● Chemical digestion involves breaking down the food
into simpler nutrients that can be used by the cells
using enzymes
● Begins in the mouth with saliva
● Continues in the stomach when gastric acids and
enzymes break down the food into simpler particles
● Continues in the small intestines as secretions are
added from the liver and pancreas
Chemicals = Chemical Digestion
Interacting with Other Systems
The digestive system works very closely with
the circulatory system to get the absorbed
nutrients distributed through your body. The
circulatory system also carries chemical signals
from your endocrine system that control the
speed of digestion.
Interacting with Other Systems
The digestive system also works in parallel
with your excretory system (kidneys and
urination). While the digestive system
collects and removes undigested solids, the
excretory system filters compounds from the
bloodstream and collects them in urine. They
are closely connected in controlling the
amount of water in your body.
Excretory System
What does the excretory system do for our bodies?
What organs make up the excretory system?
Excretory System
The main functions of the excretory system:
● Eliminate waste
● Filter cellular wastes, toxins, excess water that
result from cellular respiration
● Toxins are chemicals that could be poisonous
to the body
Excretory System
The main organs of the excretory
(urinary) system are:
● Kidneys - The two kidneys get rid
of urea, excess water, and some
other waste materials released by
the cells. These are eliminated as
urine.
● Ureters -Tubes which connect
each kidney to the bladder.
Excretory System
● Bladder - A sac-like muscular organ
which stores urine until it is
released from the body.
● Urethra - Tube through which
urine passes before it is removed
from the body
https://www.youtube.com/watch?v=WtrYotjYvtU
What Does This System Do?
What do those kidneys do? The regulation
process of body fluids and salt levels is also
called osmoregulation. The kidneys act as a
filter. Eventually all of the blood in your body
passes through the kidneys and they are able to
do their filtering magic. The kidneys pull
harmful molecules out of your bloodstream and
leave the ones that are good for you.
What Does This System Do?
The kidneys are also key players in the
hydration (water) levels for your body. Let's
say you are in the desert and you haven't
been drinking much water. Chemical signals
are sent to your kidneys to reabsorb as much
water as possible. The result is less urine
creation and your body loses less water. A
normal day has you creating about one and a
half liters of fluid.
Interacting with Other Systems
The excretory system is a close partner with
both the circulatory and endocrine system. The
circulatory system connection is obvious. Blood
that circulates through the body passes through
one of the two kidneys. Urea, uric acid, and
water are removed from the blood and most of
the water is put back into the system.
Interacting with Other Systems
The endocrine system is the major controller of
the excretory system. As levels of compounds and
fluids are monitored, kidney function must be
constantly altered to provide the best internal
environment for your cells. If you drink too much
water, hormones are released that allow for more
urine production. If you are dehydrated, less urine
will be produced. The kidneys are also tied to the
endocrine system with the adrenal gland position
on the top of each kidney. The adrenals release
adrenaline into your body.
Musculoskeletal System
What does the musculoskeletal system do for our bodies?
What organs make up the musculoskeletal system?
Musculoskeletal System
The main functions of the
musculoskeletal system:
● Provide movement and
support for the body
● Protect internal organs
● Provide attachment
sites for the muscles
Musculoskeletal System
The main organs of the musculoskeletal system are:
● Muscles
● Soft tissue that has the ability to relax and
contract in order to initiate movement within
the body
Musculoskeletal System
Bones
● Provide shape and
support for the body
● Protection for many
organs and structures
● Attachment sites for
muscles
● Some bones produce
blood cells
● Store minerals
Musculoskeletal System
There are three types of muscle:
● Cardiac muscles
● Involuntary muscle that forms the
heart
● Smooth muscles
● Involuntary muscles that control many
types of movement within the body
(such as digestion).
● Skeletal muscles
● Voluntary muscles attached to bones
and provide the force needed to move
the bones; tendons connect the
skeletal muscles to bones
Musculoskeletal System
● Joints
● A place in the skeleton where two or
more bones meet
● There are many types of joints found in
the body
Musculoskeletal System
● Ligaments
● Soft connective tissue that attach bones at the joints
● Attaches bone to bone
● Tendons
● Soft connective tissue that attaches muscles to bones
Relationships of the Major Body Systems
Even though each system in the human body
performs its own function, the different systems
work together and depend on one another for
the body to function successfully.
● Examples of relationships between the major
body systems may be:
● All body systems are dependent upon the
circulatory system to transport materials.
Relationships of the Major Body Systems
● The circulatory system works with the excretory
system to help remove wastes from the body.
● The respiratory system works with the circulatory
system to make sure that oxygen (O2) reaches
the bloodstream and carbon dioxide (CO2) is
removed from the bloodstream.
● The digestive system works with the circulatory
system to make sure that nutrients made
available by digestion (for example glucose) get
to the cells of the body.
Relationships of the Major Body Systems
● The nervous system works with the muscular and
skeletal systems to direct behavior and
movement.
● The nervous system controls internal processes in
the body (for example digestion and circulation).
● Muscles control the movement of materials
through some organs (for example the stomach,
intestines, and the heart).