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Lesson Overview
7.1 Life is Cellular
Lesson Overview
Life Is Cellular
The Discovery of the Cell
Schleiden, Schwann, Virchow:
Matthias Schleiden (1838) = all plants were made of cells
Theodor Schwann (1839) = all animals were made of cells
Rudolph Virchow (1855) = new cells were created only from division of existing
cells
These discoveries led to the cell theory:
- All living things are made up of cells.
- Cells are the basic units of structure and function in living things.
- New cells are produced from existing cells.
The Discovery of the Cell
What is the cell theory?
http://www.hippocampus.org/Biology;jsessionid=3529C2F539E99E86948A8205D1D283
F3
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The Discovery of the Cell
Hooke’s Drawing of Cork Cells
Hooke saw this and came
up with word “cell”
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Lesson Overview
Life Is Cellular
Prokaryotes and Eukaryotes
How are prokaryotic and eukaryotic cells different?
Prokaryotic cell
Eukaryotic cells
smaller
no true nucleus
simple, not many structures
no membrane-bound organelles
ex. bacteria
larger
nucleus
complex, many structures
membrane-bound organelles
ex. plant, animal cells
*** Both types of cells have genetic material and a cell membrane
Lesson Overview
Life Is Cellular
Prokaryotes and Eukaryotes
http://www.hippocampus.org/Biology;jsessionid=3529C2F539E99E86948A8205
D1D283F3
7-1
The cell theory states that new cells are produced
from
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nonliving material.
existing cells.
cytoplasm.
animals.
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7-1
The person who first used the term cell was
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Matthias Schleiden.
Lynn Margulis.
Anton van Leeuwenhoek.
Robert Hooke.
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7-1
Which organism listed is a prokaryote?
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protist
bacterium
fungus
plant
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7-1
One way prokaryotes differ from eukaryotes is that
they
• contain DNA, which carries biological information.
• have a surrounding barrier called a cell membrane.
• do not have a membrane separating DNA from the rest
of the cell.
• are usually larger and more complex.
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END OF SECTION
Lesson Overview
7.2 Cell Structure
http://vcell.ndsu.edu/animations/fly
through/movie-flash.htm
Lesson Overview
Life Is Cellular
Cell Organization
The eukaryotic cell can be divided into two major parts: the nucleus and
the cytoplasm.
The cytoplasm is the fluid portion of the cell outside the nucleus.
Lesson Overview
Life Is Cellular
The Nucleus
NUCLEUS: control center of the cell, contains DNA
DNA - instructions or blueprint for making proteins and other important
molecules
Lesson Overview
Life Is Cellular
The Nucleus
Most nuclei also contain a
small, dense region nucleolus
Nucleolus – makes
ribosomes (which eventually
make proteins)
Lesson Overview
Life Is Cellular
Vacuoles and Vesicles
VACUOLES: large, saclike, membrane-enclosed
structures that store materials such as water, salts,
proteins, and carbohydrates; much larger in plant cells
Lesson Overview
Life Is Cellular
Vacuoles and Vesicles
Vesicles –”vehicles”; used to store and move materials
between cell organelles, as well as to and from the cell
surface.
Lesson Overview
Life Is Cellular
Lysosomes
Lysosomes - small organelles filled with enzymes that function as
the cell’s “cleanup crew”.
• have hydrolytic enzymes which breakdown larger substances and
garbage (worn out organelles)
http://highered.mcgrawhill.com/sites/0072437316/student_view0/c
hapter5/animations.html
Lesson Overview
Life Is Cellular
The Cytoskeleton
Eukaryotic cells are given their shape and internal organization by a
network of protein filaments known as the cytoskeleton.
Microfilaments and microtubules are two of the principal protein filaments
that make up the cytoskeleton.
****Used for structure and movement (internal and external)
Lesson Overview
Life Is Cellular
Microtubules
Microtubules are hollow structures made up of proteins known as tubulins.
Important in cell division, where they form a structure known as the mitotic
spindle, which helps to separate chromosomes.
In animal cells, structures known as centrioles are also formed from tubulins
Microtubules help to build cilia and flagella, which enable cells to swim
rapidly through liquids.
Lesson Overview
Life Is Cellular
Organelles That Build Proteins
REVIEW: Why are proteins so important?
Organelles that help build proteins:
ribosomes
ER
Golgi apparatus
vesicles
Lesson Overview
Life Is Cellular
Ribosomes
Ribosomes - small particles of RNA and protein found throughout the
cytoplasm (in both prokayotes and eukaryotes)
Ribosomes produce proteins by following coded instructions that come from
DNA in process called translation
Lesson Overview
Life Is Cellular
Endoplasmic Reticulum
Endoplasmic reticulum, or ER – an internal membrane system; “highway”
Two kinds: rough ER and smooth ER
http://bcs.whfreeman
.com/thelifewire/defa
ult.asp - Chapter 4,
Tutorial 4.2
Lesson Overview
Life Is Cellular
Endoplasmic Reticulum
rough endoplasmic reticulum - take newly formed proteins from
ribosomes and modified and
transported
Lesson Overview
Life Is Cellular
Endoplasmic Reticulum
Smooth ER - contains collections of enzymes that perform
specialized tasks, including the synthesis of membrane lipids and the
detoxification of drugs.
Lesson Overview
Life Is Cellular
Golgi Apparatus
The proteins are bundled into tiny vesicles that bud from the ER and
carry them to the Golgi apparatus
The Golgi apparatus modifies, sorts, and packages proteins and
other materials from the ER for storage in the cell or release outside
the cell
Lesson Overview
Life Is Cellular
Organelles That Capture and Release
Energy
Chloroplasts (mostly found in plants)
Mitochondria (found in mostly all cells)
Lesson Overview
Life Is Cellular
Chloroplasts
Chloroplasts - capture the energy
from sunlight and convert it into
food that contains chemical energy
in a process called photosynthesis.
Two membranes surround
chloroplasts.
Inside the organelle are large
stacks of other membranes
(grana), which contain the green
pigment chlorophyll.
Lesson Overview
Life Is Cellular
Mitochondria
Mitochondria - power plants of the cell; convert the chemical energy
stored in food into compounds that are more convenient for the cell
to use
Two membranes—an outer membrane and an inner membrane—
enclose mitochondria. The inner membrane is folded up inside the
organelle (cristae)
Lesson Overview
Life Is Cellular
Mitochondria
Chloroplasts and mitochondria contain their own genetic
information in the form of small DNA molecules.
The endosymbiotic theory suggests that chloroplasts and
mitochondria may have descended from independent
microorganisms
http://www.sumanasinc.com/webcontent/animations/content/organelles.html
Lesson Overview
Life Is Cellular
Cellular Boundaries
cell membrane – found in all cells; regulates what goes
in and out of cell
cell wall – not found in animal cells; provides support
and protection for the cell
Lesson Overview
Life Is Cellular
Cell Membranes
Cell membranes made up of a lipid bilayer, which gives cell
membranes a flexible structure and forms a strong barrier
Phospholipid bilayer:
hydrophobic, or “water-hating” fatty acid chains (TAILS)
hydrophilic, or “water-loving,” (HEADS)
Lesson Overview
Life Is Cellular
The Fluid Mosaic Model
Most cell membranes contain protein molecules that are embedded in the
lipid bilayer. Carbohydrate molecules are attached to many of these
proteins.
Proteins used as channels
Carbohydrates used as ID markers
Lesson Overview
Life Is Cellular
The Fluid Mosaic Model
Most biological membranes are selectively permeable
Selectively Permeable/Semipermeable:
some substances can pass across them and others cannot
Lesson Overview
7.3 Cell Transport
Lesson Overview
Life Is Cellular
Passive Transport
• The movement of materials across the cell membrane
without using energy is called passive transport
• Diffusion & Osmosis
Lesson Overview
Life Is Cellular
Diffusion
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The process by which particles move from an area of
higher concentration to an area of lower concentration
Equilibrium
• Particles continuously move but NO NET CHANGE
http://programs.northlandcollege.edu/biology/Biology1111/animations/transp
ort1.html
Lesson Overview
Life Is Cellular
Facilitated Diffusion
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Molecules that cannot directly diffuse across the
membrane pass through special protein channels
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The movement of molecules by facilitated diffusion
does not require energy AND molecules move from
high to low concentration SO it is DIFFUSION.
Lesson Overview
Life Is Cellular
Osmosis: An Example of Facilitated
Diffusion
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Many cells contain water
channel proteins, known as
aquaporins, that allow water
to pass right through them.
(faster than usual)
Lesson Overview
Life Is Cellular
Osmosis: An Example of Facilitated
Diffusion
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Osmosis involves the movement of water molecules
from an area of higher concentration to an area of lower
concentration.
http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP11003
Lesson Overview
Life Is Cellular
How Osmosis Works
In the experimental setup below, the barrier is permeable to water but not to
sugar. This means that water molecules can pass through the barrier, but the
solute, sugar, cannot.
Lesson Overview
Life Is Cellular
How Osmosis Works
• More sugar molecules on the right side than on the left
• Concentration of water is lower on the right than left
• Water moves from high to low concentration
Lesson Overview
Life Is Cellular
How Osmosis Works
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When the concentration is the same on both sides of
the membrane, the two solutions will be isotonic
(“equal”)
Lesson Overview
Life Is Cellular
How Osmosis Works
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The more concentrated sugar solution at the start of the
experiment was hypertonic (more solutes/less water)
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The dilute sugar solution was hypotonic (less
solutes/more water)
Lesson Overview
Life Is Cellular
Osmotic Pressure
Lesson Overview
Life Is Cellular
Active Transport
• The movement of materials against a concentration
gradient (low to high)
• requires energy (ATP)
http://programs.northlandcollege.edu/biology/Biology1111/animations/transport
1.html
Lesson Overview
Life Is Cellular
Active Transport
Lesson Overview
Life Is Cellular
Active Transport
1. ENDOCYTOSIS
- phagocytosis
(“eating”)
- pinocytosis
(“drinking”)
2. EXOCYTOSIS
7-3
QUIZ TIME!!
Unlike a cell wall, a cell membrane
a. is composed of a lipid bilayer.
b. provides rigid support for the surrounding cell.
c. is found only in plants, fungi, algae, and many
prokaryotes.
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7-3
QUIZ TIME!!
Unlike a cell wall, a cell membrane
a. is composed of a lipid bilayer.
b. provides rigid support for the surrounding cell.
c. is found only in plants, fungi, algae, and many
prokaryotes.
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7-3
If a substance is more highly concentrated outside
the cell than inside the cell and the substance can
move through the cell membrane, the substance
will
a. move by diffusion from inside the cell to outside.
b. remain in high concentration outside the cell.
c. move by diffusion from outside to inside the cell.
d. cause water to enter the cell by osmosis.
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7-3
If a substance is more highly concentrated outside
the cell than inside the cell and the substance can
move through the cell membrane, the substance
will
a. move by diffusion from inside the cell to outside.
b. remain in high concentration outside the cell.
c. move by diffusion from outside to inside the cell.
d. cause water to enter the cell by osmosis.
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7-3
The movement of materials in a cell against a
concentration gradient is called
a. facilitated diffusion.
b. active transport.
c. osmosis.
d. diffusion.
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7-3
The movement of materials in a cell against a
concentration gradient is called
a. facilitated diffusion.
b. active transport.
c. osmosis.
d. diffusion.
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7-3
The process by which molecules diffuse across a
membrane through protein channels is called
a. active transport.
b. endocytosis.
c. facilitated diffusion.
d. osmosis.
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7-3
The process by which molecules diffuse across a
membrane through protein channels is called
a. active transport.
b. endocytosis.
c. facilitated diffusion.
d. osmosis.
Copyright Pearson Prentice Hall