Cells
The building blocks of all living
things.
Do you know why cells are
called “cells”?
 The first person to observe cells was an
English scientist named Robert Hooke.
 In 1665, Hooke looked at a piece of cork using
a microscope and drew a comparison between
what he saw and something he was already
familiar with.
 He thought that the sections making up the
cork looked like the rooms that monks lived in,
which are called “cells”.
 Hooke decided to call the cork sections “cells”,
too.
What are we going to learn?
 Cells are the small but complex building blocks
of all living things.
 Cells carry out all the activities that keep a
living thing alive.
 Cells take in nutrients, water, and air.
 Cells get rid of wastes, use energy, grow, and
reproduce themselves.
 Cells join together to form tissues, organs, and
organ systems.
 What happens when cells stop functioning
normally?
Cells
Prokaryotic
Eukaryotic
Prokaryotic
Cell
Ribosomes
Cell Wall
(Source: Cellupedia)
Flagella
Nucleulous/DNA
Cell
Membrane
The structure of prokarytic cells (Source: Glenn and Susan Toole)
Capsule
Prokaryotic Cell
Eukaryotic
Cell
Plant Cell
vacuole
Animal Cell
CELLS ALIVE
 http://www.cellsalive.com/cells/plntcell.htm
Cell Membrane
 Boundary between the inside of the cell and its
surroundings.
 The cell membrane controls the movement of
nutrients, water, salts, and other substances
into the cell and movement of waste out of the
cell.
 The membrane keeps out harmful bacteria,
viruses, and other things that could damage
the cell.
Boundaries
 List five boundaries that you can see around
you.
 For each one, tell what marks the boundary.
 List what is kept in and what is kept out by the
boundary.
 Example – A fence marks the boundary of the
yard.
 The fence keeps pet dog and young children in.
 It keeps strange dogs and bicyclists out
Cytoplasm
 This is a gel-like substance that fills the
cell and surround the organelles.
 It would be in comparison to our
environment (air, land, water)
Organelles
 Small structures inside the cell
membrane.
 Each organelle has a particular job to
do to keep the cell working properly.
 The organelles are found in the
cytoplasm that fills the cell.
What do all living things need
to stay alive?
 All living things need nutrients, water,
and air.
 All living things need a suitable place
to live.
What are the characteristics
of all living things?
Respond to their environment, inside
and out.
Organized to carry out life functions.
Grow and develop.
Energy.
Reproduce.
What do you think a single
cell needs to do in order
to stay alive?
Mitochondria
 Provide energy for the cell by breaking down
sugar.
 Known as the power house of the cell
 In a city this would be compared to power
plants
 Mitochondria burn fuel to provide our cells
with energy. A chemical reaction called
cellular respiration takes place in the
mitochondria.
 Humans cannot live without mitochondria!
 Why?
 Think about It: No organism can survive without
energy. How do you get and use energy? Draw
the concept map below, list some things in the
center box that are sources of energy for your
body. In the other boxes list ways your body uses
energy.
Sources Of
Energy
On a sheet of paper
answer the following:
 Where would you expect to find more
mitochondria-in very active cells such as
those in your heart and liver, or in less
active cells such as those in your
earlobes? Explain you answer.
Take in and use Energy
 Cellular respiration
 Mitochondria burn fuel to provide our cells with
energy. A chemical reaction called cellular
respiration takes place in the mitochondria.
 C6H12O6 + 6O2
 Glucose + oxygen
6CO2 + 6H2O + energy
carbon + water + energy
dioxide
Plant Cell’s Power House
 Plant cells like animal cells have mitochondria, but
they also have another kind of energy-converting
organelle called
a chloroplast..
The process that plants use chloroplast is called
photosynthesis.
Chlorophyll is the
chemical in the
chloroplasts that
captures sunlight.
Take in and use Energy
 Photosynthesis
The process that plants use chloroplast is called
photosynthesis.
6CO2 + 6H2O +light energy
C6H12O6 + 6O2
Carbon + water + light energy
dioxide
glucose + oxygen
Nucleus
1. Stores cell
hereditary
materials, DNA
2. Coordinates
the cells
activities
(Metabolism,
growing, protein
synthesis, cell 1. Chromosomes/chromatin: codes for the
DNA 2. Nucleolus: Membrane-less organism,
division
that manufactures ribosomes.
(reproduction)) 3. Nuclear Envelope: double-layered
3. Brain of the membrane that envelopes the contents of
the nucleus
cell
4. Nuclear Pore: regulates passage of
molecules between nucleus and cytoplasm.
Endoplasmic reticulum
 Carries materials around the cell.
 Name some things in a city that would be
like the endoplasmic reticulum.
 Sometimes known as rough endoplasmic
reticulum if ribosomes are attached.
Ribosomes
 Ribosomes
are the sites
of protein
synthesis
 1. free in the cytoplasm or
 2. attached to the surface of ER
 They would be like factories producing needed
products.
 Protein helps with growth and repair of a body.
Golgi Bodies
 1. Final sorting
and packaging
of proteins and
lipids
 2. Membrane breaks
 away as vesicles.
 3. It is like a packaging and shipping center. (The
UPS men)
 stacks of membrane-covered sacs that package
and move proteins to the outside of the cell. Golgi
bodies are the packaging and secreting organelles
of the cell.
 Note: Golgi Bodies are sometimes referred to as
Golgi Apparatus.
Lysosomes
 Lysosomes are a
special type of vesicle
that contain digestive
enzymes.
They are round structures surrounded by membranes.
Lysosomes recycle materials by breaking down
worn-out parts of a cell into smaller units. They
deliver these materials to the cytoplasm for use in
constructing new proteins. If the membrane of a
lysosome breaks, the enzymes released may also
destroy the cell itself, giving lysosomes the name
"suicide bag".
Lysosomes would be like waste processing plants.
Nucleolus
 Makes the ribosomes and found
in the nucleus.
Nucleolus
Chromosomes
 The hereditary information for the
cell.
 It is the blueprint of the cell
Vacuole
 Stores food and water until
needed or waste until it is time to
leave the cell.
CELL WALL
 Prokaryotic cells and plant cells both
have a rigid cell wall made up of
polysaccharides. The cell wall provides
and maintains the shape of these cells
and serves as a protective barrier.
 Can be also found in fungi cells.
Write a Dialogue:
 A dialogue is a conversation between at
least two people. Choose two of the
organelles of a plant or animal cell. Then
write a dialogue between them in which
they argue about which of them is more
important to the cell’s survival.
PASSIVE TRANSPORT
 The movement of substances
through the cell membrane without
the input of energy.
 Diffusion
 Osmosis
 Facilitated diffusion
Cells at Work
Energy for Life
Diffusion- the
movement of molecules
from an area of greater
concentration to an area of lesser
concentration.
Osmosis
 http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htm
Osmosis: the movement
of water molecules from
an area of high
concentration to an area
of low concentration.
ACTIVE TRANSPORT
energy –requiring process in which transport
proteins bind with particles and move them
through a cell membrane.
http://www.people.virginia.edu/~rjh9u/pumpanim.html
http://www.brookscole.com/chemistry_d/templates/student_resources/shared_
resources/animations/ion_pump/ionpump.html
 Endocytosis-the process of taking
substances into the cell. Endo means
into.
 Exocytosis –releasing substances out
of the cell.
Exo means to exit.
Cell
Division
Mitosis occurs in
Body cells, like skin,
Nerves, heart.
Mitosis – the process in which
the nucleus divides to form two
identical nuclei
Meiosis
 The process of cell division in sexually
reproducing organisms that reduces the
number of chromosomes in reproductive
cells from diploid to haploid, leading to
the production of gametes, sex cells like
sperm and eggs, in animals and spores
in plants.
 Found in egg and sperm cells
When Cells Get Together
Levels of Organization
Living things have different levels of
organization. The simplest level of organization is
that of the cell. A group of cells with a similar
function is called a tissue. Groups of tissues
working together to perform a common function are
called organs. An example of this would include the
nervous, muscle, and other tissues which make up
the heart. Groups of organs working together to
perform a common function are referred to as a
system or organ system. The blood vessels,
blood, and the heart are organs which work together
to form the circulatory system. Many different
systems function together to allow a complex
organism to function.
Cells
Nerve cells
Tissues
Nerve tissue
Brain /organ
Organ Systems
Nervous system
Organisms
http://daphne.palomar.edu/cc
arpenter/Lectures/levels~1.p
pt#1
http://www.usoe.k12.ut.us/cu
rr/science/core/7thgrd/sciber
7/CELLS/HTML/LEVLQUIZ.HT
M
Homeostasis
All the components of the living things, from the cells
and the organelles within them to the organ
systems of complex organisms must interact to
maintain a balanced internal environment within
the organism. Organisms possess many control
mechanisms to detect internal and external
changes and make changes to correct any
deviations. This maintenance of a stable internal
environment by an organism is called
homeostasis. Homeostasis in an organism is
constantly threatened. Failure to respond
effectively can result in disease or death.
EQUILIBRIUM
 This occurs when molecules of one
substance are spread evenly (equal)
throughout another substance.