Transcript Characteristics of Life

Objective: Identify functions of organelles found in
eukaryotic cells, including the nucleus, cell membrane,
cell wall, mitochondria, chloroplasts, and vacuoles. (
ACOS #2)
Living Things have Cells
Cells
2 Types of Organisms
 All living things are
 Unicellular- single celled
composed of 1 or more cells.
 A cell is a membrane-covered
structure that contains all of
the materials necessary for
life.
 Membrane separates the
contents of the cell from it’s
environment.
 Most cells are too small to be
seen with the naked eye.
organisms
 Multicellular- many celled
organisms
Unicellular Organisms
Characteristics
 Single celled
 Various modes of locomotion
1) Flagella
2) Cilia
3) Pseudopods
 Asexual reproduction- a
single parent produces
offspring that are identical
to the parent; most
unicellular org. reproduce
this way
 Examples: bacteria, some
kinds of fungi, and most
protists
 Some live in colonies or
singularly
 Cells are identical
 Must carry out all life
processes
Unicellular Organisms Video
Multicellular Organisms
Characteristics
 Made of many cells
 Specialization: Each type of cell
 Grow by making more small
has a particular job; For
example- cardiac muscle cell is
specialized muscle cell (Heart
muscle cells contract and make
the heart pump blood.)
 Sexual reproduction: two
parents produce offspring that
will share characteristics of both
parents. Most animals and
plants reproduce this way.
cells, not by making cells
larger
 Larger size: Many are small,
but usually larger than singlecelled organisms
 Longer life: Life span is not
limited to the life span of any
single cell
Multicellular Organisms Video
Cells and the Cell Theory
 Robert Hooke- first person to describe cells
 Hooke built a microscope to look at tiny objects.
 Looked at a thin slice of cork (from the bark of trees)
 Cork looked like little boxes
 Cell means “little rooms” in Latin
Anton van Leeuwenhoek
 Dutch merchant
 Made his own microscope
 Looked at pond scum
 Saw small organisms in the water; He named them
animalcules (little animals)
 1st person to see bacteria and yeasts (both are
unicellular organisms)
The Cell Theory
States
Contributors
 All organisms are made of
 Matthias Schleiden- studied
one or more cells.
 The cell is the basic unit of
structure and function of all
living things.
 All cells come from existing
cells.
plants
 Theodor Schwann- studied
animals
 Rudolf Virchow- all cells
come only from other cells
Parts of a Cell
Cell Membrane
Cytoplasm
 Surrounds all cells
 Gelatin-like substance
 Serves a boundary between
 Inside the cell
cell and external
environment
 Protective layer that covers
the cell’s surface
 Acts as a barrier
 Controls materials going into
and out of the cell
 Holds all the cell’s organelles
Parts of a Cell (cont.)
Organelles
 Tiny, membrane-bound cell
structures
 Perform specific functions
within the cell
 Different types of cells have
different organelles
Pictures of bacterial, plant, and
animal cells with organelles
Parts of a Cell (cont.)
Nucleus
Cell Wall
 Organelle inside cells
 Rigid outside layer of plant
considered to be the “brain”
 Controls all cell activities
 Contains the
deoxyribonucleic acid (DNA)
 DNA- genetic material that
carries information needed to
make new cells and new
organisms
and bacterial cells
 Provides structure and
protection
 Separate inside of cell from
outside environment
Parts of the Nucleus
 Nuclear membrane/envelope- membrane that
surrounds the nucleus; protects the nucleus; materials
pass in and out through pores
 Chromatin- thin strands floating in nucleoplasm;
contain genetic material- instructions for directing the
cell’s functions
 Nucleolus- small, round structure; produces
ribosomes
Parts of a Cell (cont.)
Mitochondria
Endoplasmic Reticulum
 Rod-shaped structures
 A maze of passageways
 Known as the “powerhouses”
 Carry proteins and other
of the cell
 Convert energy in food
molecules to energy the cell
can use to carry out its
functions
materials from one part of the
cell to another
Parts of a Cell (cont.)
Ribosomes
Golgi bodies
 Small, grain like bodies
 Look like flatten sacs and
 Float in the cytoplasm and
tubes
 Thought of as cell’s mail
room
 Receive proteins and newly
formed materials form the
ER, package them, and
distribute them to other parts
of the cell
attached to endoplasmic
reticulum
 Factories to produce proteins
Parts of Cell (cont.)
Chloroplasts
Vacuoles
 Green structures floating in
 Water-filled sac floating in the
the cytoplasm
 Found in the cells of plants
and some other organisms
 Capture energy from sunlight
and use it to produce food for
the cell
cytoplasm
 The storage area of cells- food,
waste products, and other
materials.
 Most plant cells have one large
vacuole.
 Some animal cells do not have
vacuoles; others do.
Parts of Cell (cont.)
Lysosomes
 Small, round structures
 Contain chemicals that break
down certain materials in the
cell
 Cell’s cleanup crew
Specialized Cells
 Plants and animals contain many cells.
 In multicellular organisms, the cells are often quite
different from each other and are specialized to
perform specific functions.
 In many celled organisms, cells are often organized
into tissues, organs, and organ systems.
Cell Size
A Few Large Cells
Many Small Cells
 Most cells are small.
 Physical reason why most
 A few cells are big.
cells are so small
 Cells take in food and get rid
of wastes through their outer
surface
 As cells get larger, they need
more food and produces
more waste.
 Therefore, more materials
pass through its outer surface
 A chicken egg is one big cell.
Cell Structures and Their Functions
Cell Structures and Their
Functions
Structure: Nucleus
Function: Controls all of the
cell’s functions
Structure: Cell Membrane
Function:
Structure: Cell Wall
Function:
Structure: Ribosome
Function:
Structure: Endoplasmic
Reticulum
Function:
Structure: Golgi apparatus
Function:
Structure: Vesicle
Function:
Structure: Mitochondria
Function:
Structure: Chloroplast
Function:
Structure: Lysosome
Function:
Plant
Animal
X
X
Bacterial
Structure of Cells Video
Two Kinds of Cells
 All cells have cell membranes, organelles, cytoplasm,
and DNA.
 Two basic types of cells- cells without a nucleus and
cells with a nucleus.
 Cells that have no nucleus are prokaryotic cells.
 Cells that have a nucleus are eukaryotic cells.
 Prokaryotic cells are further classified into two groups:
eubacteria and archaebacteria.
Two Kinds of Cells
Prokaryotic Cells
Eukaryotic Cells
 Cells without nucleus
 Cells with nucleus
 Single-celled organisms
 Most are multicellular
 No membrane bound
 Membrane bound organelles
organelles
 Two groups: Eubacteria and
Archaebacteria
 Include animals, plants, and
fungi, but not archaebacteria
or eubacteria
Prokaryotic Cells and Prokaryotes
(p. 27)
Eubacteria
Archaebacteria
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 Called archaea (ar KEE uh)
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Most common prokaryotes
Commonly called bacteria
No nucleus
DNA is long, circular molecule
that’s shaped sort of like a rubber
band
No membrane covered organelles
Have ribosomes- tiny, round
organelles made of protein and
other materials
Cell wall with cell membrane just
inside
Some live in soil and water and
others live in other organisms
 Not as common as bacteria but
1.
2.
3.

similar in some ways
Single-celled
Have ribosomes, cell
membrane, and circular DNA
Lack nucleus and membranebound organelles
Also called extremophiles due
to living in places where
conditions are extreme
Eukaryotic Cells and Eukaryotes
 Euk. cells are the largest cells. Plant cells and animals cells
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are euk. cells.
Microscopic but 100X larger than bacterial cells
Have a nucleus
Nucleus holds the cell’s DNA
Have organelles that have different functions (specific jobs)
Organisms made of euk. cells are called eukaryotes.
Eukaryotes are multicellular, meaning “many cells.”
Examples: Multicellular eukaryotes- Animals, plants, some
protists such as green algae, and fungi such as mushrooms;
Unicellular eukaryotes- protists such as amoebas and fungi
such as yeasts
Plant and Animal Cells
plant cell
animal cell
Plants and animals are made up of many eukaryotic cells.
Video Quiz: The Cell is the Basic
Unit of Structure and Function
References
 Cells: The Basic Units of Life. Ancient Lights.
(1994). Retrieved August 29, 2009, from
Discovery Education:
http://streaming.discoveryeducation.com/