Transcript Cells - Marric.us

Cells and Organelles
Chapter 4 – Cells: The
Basic Units of Life
M.Elizabeth
Martin Luther King, Jr. JHS
2005
Chapter 4 Cells: The Basic Units of Life
4.1 Organization of Life
 4.2 The Discovery of Cells
 4.3 Eukaryotic Cells: The Inside Story
 Review

4.1 Organization of Life
Cells: Starting Out Small
Tissues: Cells Working in Teams
Organs: Teams Working Together
Organ Systems: A Great Combination
Organisms: Independent Living
The Big Picture –
Populations
Communities
Ecosystems
Biosphere
4.2 The Discovery of Cells
Seeing the First Cells
Seeing Cells in Other Life Forms
The Cell Theory
Cell Similarities
Cell Membrane
Hereditary Material
Cytoplasm and Organelles
Small Size
Giant Amoeba Eats New York City – Surface to
Volume Ratio limitations
The Benefits of Being Multicellular
Two Types of Cells
Prokaryotes
Eukaryotic Cells
4.3 Eukaryotic Cells: The Story Inside
Holding It All Together
Cell Membrane
Cell Wall
The Cell’s Library - nucleus
Protein Factories – ribosomes
The Cell’s Delivery System
The Cell’s Power Plants
Mitochondria
Chloroplasts
Endosymbiotic Theory
The Cell’s Packaging Center
The Cell’s Storage Centers
Packages of Destruction
Plant or Animal
4.1 Organization of Life


Cells: Starting Out Small
Terms
 Tissue – a group of similar cells that work
together to perform a specific job (function)
in the body
 Organ – A combination of two or more
tissues that work together to perform a
specific function in the body
 Organ System – Groups of organs working
together to perfomr body functions
 Organism – anything that can live on its own
 Unicellular – made of one cell
 Multicellular – made of many cells
4.1 Organization of Life


Cells: Starting Out Small
Terms (continued)
 Population – a group of individuals of
the same species that live together in
the same area at the same time
 Community – All of the populations of
different species that live and interact
in an area
 Ecosystem – a community of organisms
and their non-living (abiotic)
environment
 Biosphere – all life on Earth
Cells Starting Out Small

Example of a cell that is large
enough to be seen without a
microscope:
 Chicken egg – The first cell
of a chick is yellow with a
tiny white dot in it and it is
surround by a clear jellylike
fluid called egg white The
white dot divides over and
over again to form a chick.
The yellow yoke from the
first cell and the egg white
provide the nutrients for
the developing chick’s cell
growth.
Humans have about 200 different kinds of cells
and each type is specialized to do a particular job.
Tissues: Cells Working Together
Tissues are groups of cells that work together
to perform a specific function
Organs: Tissues working together
Two or more tissues working together
The skin is the body’s largest organ. An
average person’s skin has a mass of about
4.5 kg (almost 10 lbs)
In your lifetime you will shed about how much
dead skin?
18 kg (almost 40 lbs)
Plant Organs
1.
2.
3.
4.
5.
6.
Leaf
Flower
Fruit
Stem
Seed
Root
http://www.urbanext.uiuc.edu/gpe/case1/c1m1app.html
Organ Systems: A Great Combination
Organs working together in groups to
perform particular functions are called
organ systems.
 Organ system card activity

From Cell to Organ System

Muscle cell makes up heart tissue that
makes up a heart (organ) that is part of the
circulatory/cardiovascular system.
Respiratory System


Inhalation (Breathing in)
Exhalation (Breathing out)
Humans in and out
the mouth
Fish in the mouth
with water through
the gills and out
Skeletal System
Skeletal System – Bone Tissue
Note the
haversian canal
and surrounded
by osteocytes
and a mineralized
matrix
Bone has calcium salts in the matrix, giving it greater strength. Bone also
serves as a reservoir (or sink) for calcium.
Protein fibers provide elasticity while minerals provide strength.
Two types of bone occur.
Dense bone has osteocytes (bone cells) located in lacunae connected
by canaliculi. Lacunae are commonly referred to as Haversian canals.
Spongy bone occurs at the ends of bones and has bony bars and
plates separated by irregular spaces. The solid portions of spongy bone
pick up stress..
Organisms: Independent Living

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
Anything that can live on its own is an
organism.
 Recall virus are not considered living –
here is another reason way – because
they cannot live on their own.
Unicellular organisms– one cell, usually
requires a microscope to view.
Multicellular organisms
 A group of cells that can remain alive only
together as a unit.
Plant Organ Systems


In flowering plants, the flower
functions in sexual reproduction.
The essential flower parts are:
 male parts called the stamens
 female part called the pistil.
The stamen is the male plant organ and has
two parts: anthers and filaments.
Pollen (usually yellow) is produced at the ends of
the stamens on structures called anthers.
 Anthers are supported by a thread-like
structure called a filament.

The pistil which is the female plant organ
has three parts: stigma, style, and ovary.
The stigma is the sticky surface at the top of
the pistil; it traps and holds the pollen.
 The style is the tube-like structure that
supports the stigma.
 The style leads down to the ovary which
contains the ovules.

During the process of pollination
1.
2.
3.
4.
5.
Pollen moves from the male parts to the female parts.
Pollen grains land on the stigma
A tiny tube grows from it and down the style into the
ovary.
Sperm cells travel down the tube from the pollen
grains and join with an egg cell in the ovule resulting in
fertilization.
The fertilized ovule becomes the seed and the ovary
becomes the fruit.
The Big Picture



Organisms interact in populations:
 All of the red oak trees make up the
forest’s red oak population.
Communities include two or more different
populations living in the same area.
 The populations of foxes, oak trees,
lizards, flowers, and other organisms in a
forest are all part of a particular forest
community
Ecosystems: Community and all nonliving
things (abiotic) like: water, soil, rocks,
temperature, and light.
Sample Ecosystem
What makes up a community?
A community is made up of the populations of living
things (biotic) in the ecosystem. So the community
in the ecosystem is the deer, butterflies, trees,
grasses, and flowers.
4.2 The Discovery of Cells
Seeing the First Cells

Robert Hooke: 1665 British
scientist. Looking for
demonstration for a
scientific meeting. Hooke
looked at a piece of cork
and noticed hundreds of
little boxes.
 He named the little boxes
cells which means in Latin
“little rooms”
http://www.roberthooke.org.uk/
Seeing Cells in Other Life Forms

Anton Leeuwenhoek
 Used his own handmade microscope
that be built to look more closely at
fabrics he was buying while in
Holland.
 Looked at blood, teeth tarter and all
kinds of living cells. He also
discovered that yeasts that make
bread are unicellular.
The Cell Theory
1.
2.
3.
All organisms are composed of one or
more cells
The cell is the basic unit of life in all
living things
All cells come from existing cells
Three scientists involved:
1.
2.
3.
Matthias Schleiden (1838) German, plant cells
Theordor Schwann (1839) German, animal cells.
Wrote the first two tenets of the theory.
Rudolf Virchow (1858) German doctor. Wrote
the last tenet after observing that cells could
not develop from anything but other cells.
Cell Similarities

All Cells have the following in common:
Cell membranes – barriers to the outside world.
Control the passage of materials into and out of
the cell.
 Hereditary Material – DNA (deoxyribonucleic acid) or
sometimes RNA (ribonucleic acid)
 Cytoplasm and Organelles
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Cytoplasm is the fluid that is contained within the
cell and that the organelles are found. Not all cells
have membrane-bound organelles (nucleus,
mitochondria, chloroplasts, golgi, etc.)
Small size – too small to be seen by the eye.
Giant Amoeba Eats New York City

The surface area and volume of a cube
can be found with the following
equations: SA = 6L2 , and V = L3
where
S = surface area (in units squared),
V = volume (in units cubed), and
L= the length of one side of the cube.
What is important about Surface-to-Volume

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Cells need food, energy, and to remove
wastes and heat in proportion to its size or
volume, V
All of these things must be transported
across the cell's surface, S, so the rate at
which needs can be met is proportional to
the surface area.
Size small structures that are more
"surfacey" than large structures can meet
their needs faster.
This can be seen by considering 2 cubes of
different size.
Surface to Volume Ratio
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Surface Area = S = 6r2
Volume = V = r3
Surface/Volume = S/V = 6/r
It is harder for
nutrients and wastes
to get in and out from
the central area of
larger cells
Cell Surface Area to Volume
What are the two types of cells?
 Eukaryotic
cells – have a nucleus
and other membrane bound
organelles
 Prokaryotic cells – do not have a
nucleus or other membrane bound
organelles
Prokaryotes
 no
nucleus
 no membranes except cell membrane
 bacteria or blue/green algae
 very small
 almost always unicellular
 ribosomes
 single circular DNA chromosome
Eukaryotes
 nucleus (eukaryotic means “true
nucleus” in Greek)
 membrane bound Organelles
 larger in size
 uni or multicellular
 many linear DNA chromosome
 evidence indicates that they first
appeared about 2 billion years ago
during the Precambrian Era.
 animals, plants, fungi, protista
4.3 Eukaryotic Cells: The Inside Story

Holding it all together
 Cell Membrane - phospholipids
 Cell Wall
 Plant
cells – cellulose cell wall
 Fungal cells – chitan usually
Cell Membrane
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

The cell membrane is a structure that
forms the outer boundary of the cell and
allows only certain materials to move into
and out of the cell.
Food, oxygen and water move into the cell
through the membrane. Waste products
also leave through the membrane.
Cells that perform photosynthesis (plants
and some protists) take in carbon dioxide
through the cell membrane instead of
oxygen.
Cell Membrane Function

The cell membrane allows only certain
materials to move in and out of the cell
Looks like this
Functions like this
Cell Membrane Composition

The current best model of what a cell
membrane looks like is in the figure
below. As you can see it is made up of
three parts.
phospholipids (magenta and green)
 proteins (orange and red)
 carbohydrates (black). Carbohydrates can be
attached to either the phospholipids or the
proteins in the cell membrane.

The Cell’s Library - Nucleus

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Nucleus – means “kernel or nut” because it
is the “essence of cells”
In all except for plant cells is the largest
and most visible organelle.
Is called the control center of the cell
Stores DNA which has the information to
make all of the cell’s proteins.
The dark central area is called the
nucleolus which stores materials to make
ribosomes in the cytoplasm (RNA)
Protein Factories - Ribosomes
Proteins are the building blocks of all
cells
 Proteins are made up amino acids
 Ribosomes make proteins by linking
amino acids together in accordance
with the information stored in DNA
 All cells have ribosomes because all
cells need proteins to live
 Ribosomes are not covered with a
membrane – NOT Membrane Bound

Review
Do prokaryotic cells have ribosomes?
Yes, prokaryotes have ribosomes
because ribosomes are essential and
are not membrane bound.
Cell’s Delivery System –
Endoplasmic Reticulum
 Membrane covered
 Flattened sacks stacked side by side
 May be covered with ribosome (rough
endoplasmic reticulum)
 Makes lipids and other materials for
use inside and outside of the cell.
 Is an internal delivery system of the
cells (tubular connections – like cars
moving through tunnels
Review Question
Are endoplasmic reticulum found in
prokaryotes?
No, prokaryotes do not have organelles
that are membrane bound.
Cell Power plants
Mitochondria and Chloroplasts
 All cells need energy
 Mitochondria and chloroplasts both
have membranes
 Mitochondria are in all eukaryote cells
 Mitochondria create useable energy
(ATP) from sugar using oxygen
 Only plant cells contain chloroplasts
 Plant cells create sugar using sunlight,
carbon dioxide, and water.
Cell Power plants
Mitochondria and Chloroplasts


All cells need energy
Mitochondria (2 or more mitochondrion)
 Have 2 membranes: folded inner
membrane and an outer membrane.
 Where ATP is made
 Needs oxygen to perform cellular
respiration where glucose (sugar) is
broken down to release energy in the
form of ATP
Chloroplasts
 Plants and algae have this organelle
that can covert sunlight energy, CO2
and H2O into glucose (C6H12O6)
 Chloroplast means “green structure”.
 Chlorophyll make chloroplasts green
and is the compound that captures
the light energy
 Both mitochondria and chloroplasts
have separate DNA.

Endosymbiotic Theory
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Endo – inside, internal
Symbiotic- living together, mutually
beneficial
The Endosymbiotic Theory is an explanation
for the origins of mitochondria and
chloroplasts.
The theory states that mitochondria and
chloroplasts originated as prokaryotic cells
that were eaten (endocytosis) and instead
of being digested they survived and
continued functioning

Lines of evidence for the Endosymbiotic
Theory:
1. Mitochondria and chloroplasts are
about the same size as bacteria
(prokaryotes)
2. Mitochondria and chloroplasts are
surround by two membranes
The inner membrane is thought to be the original
bacterial cell membrane and the outer
membrane created during endocytosis.
3. Mitochondria and chloroplasts contain a
separate circular DNA which is
duplicated when mitochondria and
chloroplasts created.
The Cell’s Packaging CenterGolgi complex
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The Golgi complex modifies and packages
compounds such as lipids or proteins.
Golgi look like endoplasmic reticulum (ER)
but are usually located closer to the cell
membrane than ER.
Final modified products are enclosed in a
piece of the Golgi membrane that pinches
off to form a small compartment (vesicles)
that transport the modified
The Cell’s Storage Centers

The cell’s storage centers are:
 Vesicles
 Vacuoles
Vesicles are membrane covered
compartments that are found in all
eukaryotic cells
 Vacuoles are membrane covered
compartment that contain water and
other liquids that help support the
plant cells.

Special Vesicles
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
Contractile vacuoles are a type of vesicle
that helps to control excess fluid in some
unicellular organisms.
Breath out – exhalation results from a
contraction of the diaphragm.
Lysosomes are specialized vesicles that
contain digestive enzymes that get rid of
waste materials and old cell parts, protect
cells from foreign invaders, and helps
digest food particles.
Endoplasmic reticulum
Nucleolus
Vesicles
Golgi complex
Cytoplasm
Ribosomes
DNA
Nucleus
Mitochondria
Cell membrane
Central Dogma
DNA to Proteins
Review
Organs
1. (Organs or Organelles) ___________are
made up of various tissues that work
together to perform a specific job.
mitochondria
2.The role of the cell’s ____________
(nucleus or mitochondria) is to release
energy that can be used to power various
cellular processes.
3. Unlike animal cells, plant cells have
chloroplasts
_____________(nuclei
or chloroplasts)
to capture energy from the sun.
4. DNA, the genetic material of a eukaryotic
nucleus
cell, is located in the cell’s ___________
(nucleus or ribosome).
Review
5. Cells that have no membrane-covered organelles
prokayotic
are _____________
(prokaryotic or eukaryotic).
6. A part of the endoplasmic reticulum can pinch
lysosome
off and form a______________
(lysosome or
vacuole), which contains digesting enzymes.
7. Which of the following statements is not part of
the cell theory?
a. The most basic component of any organism is
the cell.
b. All cells originate from other cells.
c. All cells have a nucleus and a cell membrane.
d. All living things are made up of one or more
cells.
c. All cells have a nucleus and a cell membrane
8. A life scientist who observes the relationships
between plants, animals, weather,and soil on a
ecosystem (ecologist)
mountaintop is studying a(n) ________________
a. community.
c. ecosystem.
b. population.
d. organism.
9. Which of the following is not found in plant
cells?
a. lysosomes
c. cell membrane
b. ribosomes
d. Golgi complex
10. Which of the following contain cellulose?
a. all plant cell walls
c. all eukaryotic cells
b. all mushroom cells d. some prokaryotic cells
11. Which part of a cell manufactures lipids?
Endoplasmic reticulum
__________________
a. nucleolus
c. cell membrane
b. endoplasmic reticulum
d. vesicles
12. Materials that are to be released outside the
cell are transported to the cell membrane in a
small compartment that has pinched off of the
a. nucleus.
c. rough ER.
b. contractile vacuole. d. Golgi complex.
13. Which of the following is not a characteristic
of bacteria?
a. They are prokaryotes.
b. Their DNA is one long, circular molecule.
c. They have an endoplasmic reticulum.
d. They have a cell membrane.