The Cell
1.1 Characteristics of Life
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Living things have organization
Living things are able to grow and
develop
Living things are able to respond to
their environment
Living things are able to reproduce
1.1 Needs of Life
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All organisms need energy to carry out
life’s activities
The energy used by almost all
organisms comes from the sun.
Plants and some bacteria can capture
the energy from the sun and use it to
make food.
Other organisms eat plants or other
animals to get their energy
1.1 All living things are made
of cells.
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The cell is the smallest unit of a living
thing
Some organisms are made of a single
cell. These organisms are unicellular
and usually are to small for you to see
by yourself.
Most organisms you can see like a frog
are made up of many cells and are
multicellular.
Unicellular Algae
Multicellular Frog
1.1 Unicellular vs. Multicellular
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Unicellular organisms have the
same needs and characteristics of
life as multicellular organisms.
Multicellular organisms have bodies that
are more complex, different body parts
that perform different functions.
Multicellular organisms have different
types of cells. These cells work together
to carry out the basic activities of life.
1.1 The Microscope
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Most cells are microscopic, too small to
see without the aid of a microscope.
A microscope is an instrument that
makes an object appear bigger than it
is.
The invention of the microscope lead to
the discovery of cells.
1.1 Microscope
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Robert Hooke
and Anton Van
Leeuwenhoek
(LAY- vuhn-hook)
were among the
first people to
describe cells.
1.1 Cell Theory
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Once cells were discovered people
started asking, who has them, where do
they come from?
The observations and evidence
gathered by many scientists over a long
time resulted in the cell theory.
1.1 Cell Theory
1. Every living thing is made of one or
more cells
2. Cells carry out the functions need to
support life
3. Cells come only from other living cells.
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A scientific theory is a widely accepted
explanation of things observed in
nature.
1.1 Louis Pasteur
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French Scientist
Discovered bacteria in spoiling milk
He developed a process called pasteurization, in
which heat is used to kill bacteria and therefore
keep milk fresh longer.
Pasteur discovered that bacteria could not be
formed by spontaneous generation. They could
only come from other bacteria cells.
1.1 Question: A
_____organism is made of
one cell.
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A. Frog
B. Multicellular
C. Unicellular
D. Human
E. Dog
1.1 Question: Which scientists
were the first to look at cells
under a microscope?
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A. Louis Pasteur
B. Gregor Mendel
C. James Watson
D. Robert Hooke and Anton Van
Leewenhoek
E. Francis Crick
1.1 Question: Which scientist
discovered bacteria?
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A. Francis Crick
B. Gregor Mendel
C. James Watson
D. Robert Hooke and Anton Van
Leewenhoek
E. Louis Pastuer
1.1 Question: Which of the
following is part of the cell
theory?
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A. Cells carry out the functions to
support life
B. Cells only come from other cells.
C. Every living thing is made of at least
one cell.
D. All of the above
E. None of the Above
1.2 Cells are Diverse
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Cells can differ in size and shape
The inside of one cell can be different
from that of another cell.
All Cells have this in common.
1.
2.
3.
4.
Cell Membrane
Cytoplasm
DNA (differences)
Ribosomes (differences)
2 Types of Cells
Prokaryotes
 Single celled
 Simple
 Smaller
 No cell parts
 DNA sprinkled through
out
 Examples= Bacteria,
algae
Eukaryotes
 Multicellular
 Complex
 Bigger
 Many cell parts
 DNA in the nucleus
 2 types= Plant and
animal cells
 Examples- Humans,
plants, dogs
Animal vs Plant Cell
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Animal cells are round and plant cells
are rectangular
Plant cells have 3 parts that animal
cells don’t have: cell wall, chloroplasts,
and a large central vacuole
1.2 Parts of a Eukaryotic Cell
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Cell membrane- encloses the inside of
each cell and protects it. Any material
moving in or out the cell must pass
through the cell membrane.
Cytoplasm- is gelatin like substance
where most of the work of the cell is
carried out.
1.2 Parts of a Cell
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In a eukaryotic cell, most of the
genetic material is stored in the
nucleus, these cells are more
complicated and have many more parts
then a prokaryotic cell.
Scientists use the word organelle to
describe any part of the cell enclosed
by a membrane.
1.2 Parts of a Cell
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The largest organelle that contains most of
the genetic material is called the nucleus.
The nucleus is like the control center for a
eukaryotic cell. It stores the instructions the
cell needs to function.
Most unicellular organisms are prokaryotic,
and most multicellular organisms are
eukaryotic. Plants and animal cells are
eukaryotes.
1.2 Cell Parts
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Plant cells also have cell walls. A cell
wall is a tough outer covering that lies
just outside the cell membrane.
The cell wall supports and protects the
cell.
Having a cell wall is one way in
which plant cells differ from animal
cells.
1.2 Cell Parts
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No cell can live without energy. Plants
absorb energy from the sun.
Plant cells have chloroplasts which are
organelles that use energy from the sun to
make sugars.
Some of the sugar is used right away and
some is stored.
1.2 Cell Parts
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Ribosomes are tiny
structures located through
the cytoplasm and in the
endoplasmic reticulum.
Ribosomes use information
from the nucleus to build
molecules called proteins.
1.2 Cell Parts
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No cell can stay alive without energy!
That means they/you need to eat or absorb
energy from some source
Plants get their food from the sun through
photosynthesis and their chloroplasts
Animals must eat food to get their energy
Both Plant and Animal cells must process the
food
Cell Parts
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Mitochondria are the organelles that
allow plants and animals to use energy.
Mitochondria use oxygen to get energy
from processing food.
1.2 Cell Parts
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The endoplasmic reticulum works with
the ribosomes to build proteins but it is also
a part of the cellular transport system.
Pieces of endoplasmic reticulum break off to
form small packages called vesicles.
The vesicles carry processed materials to an
organelle called the golgi apparatus.
1.2 Cell Parts
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The Golgi apparatus takes the materials
and finishes processing them.
Cells store water, sugar, and other materials.
Cells must also store waste materials.
Vacuoles function with the cell membrane
to move materials in and out of the cell.
They also can store water, waste, and other
materials. The are found in plant cells.
1.2 Cell Parts
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Lysosomes are the animal cells version
of vacuoles. Lysosomes can hold
materials and contain chemicals that
can break down nutrients, old cell parts,
and other waste.
1.2 Question: A _____cell is
simple and only has a single
cell.
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A. Large
B. Eukaryotic
C. Elephant
D. Prokaryotic
E. Multicellular
1.2 Question: The ___holds
the genetic material and is the
control center for the cell.
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A. Mitochondria
B. Cell Membrane
C. Cell Wall
D. Ribosomes
E. Nucleus
1.2 Question: Which 3 parts
do only plant cells have?
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A. cell wall, large vacuole, and nucleus
B. chloroplasts, cell wall, and ribosomes
C. cell wall, chloroplasts, and large
vacuole
D. cell wall, cell membrane, chloroplasts
E. None of the above
1.2 Question: Which organelle
uses oxygen to energy from
processing food?
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A. Mitochondria
B. Chloroplast
C. Ribosome
D. Endoplasmic Reticulum
E. Nucleus
1.2 Question: Which organelle
uses the sun to make sugar?
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A. Mitochondria
B. Chloroplast
C. Ribosome
D. Endoplasmic Reticulum
E. Nucleus
1.3 Cell Type
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Organisms can be classified by their cell
type.
Unicellular organisms have prokaryotic
cells
Multicellular organism have eukaryotic
cells.
1.3 Cells can Specialize
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Most multicellular organisms consist of
many different types of cells that do
different jobs. For example most animals
have blood cells, nerve cells, and muscle
cells.
The cells are specialized.
Specialization of cells means that specific
types of cells perform specific functions.
1.3 Specialization
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This specialization is why a single cell from a
multicellular organism cannot survive on its
own.
All the cells in your body work together.
You can think of the cells in an organism as
members of a community.
The size and nature of the community differ
from organism to organism.
1.3 Community of Cells
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Cells are the smallest unit.
In complex animals and plants, cells are not
only specialized but grouped together in
tissues.
A tissue is a group of similar cells that are
organized to do a specific job.
Examples- connective, muscle, nervous, and
epithelial (skin)
1.3 4 Types of Tissue
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Epithelial Tissue (skin)- provides
protection and allows for absorption
and secretion
Nerve Tissue- transmits or sends
electrical impulses from one part of the
body to another
1.3 4 types of tissue
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Muscle Tissue- consists of bundles of
long and narrow cells that can contract or
shorten. They make all movement possible.
Connective Tissue- joins body parts
together providing protection and support.
Tendons and ligaments are examples.
Together tissues provide protection and
support.
1.3 Community of Cells
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An organ is made of different tissues
working together to perform a particular
function.
Organs represent another level of
organization.
Examples- eye, heart, and leaf
So far we have cells  tissue  organ
1.3 Community of Cells
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Different organs and tissues working
together form and organ system.
An organism may only have a few organ
systems while others have many.
Humans have about 10 organ systems.
The nervous system for examples
includes: brain, spinal cord, nerves, and
sensory receptors in organs such as the eyes
and ears.
1.3 Organization
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Cells  tissues  organs organ
systems -> Organism
Examples of organ systems:
digestive system, reproductive system,
respiratory system, and skeletal system
1.3 Question: Eukaryotic
organisms have ____cells that
each do a particular job.
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A. Large
B. separated
C. Specialized
D. Colorful
E. Small
1.3 Question: A ____is a
group of similar cells working
together.
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A. Organ
B. Organ System
C. Cell
D. Tissue
E. Organism
1.3 Question: An____is made
of different tissues working
together.
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A. Organism
B. Organ System
C. Cell
D. Tissue
E. Organ
1.3 Question: Our digestive
system is an example of
an____.
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A. Organ
B. Organ System
C. Cell
D. Tissue
E. Organism