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7-1 Life Is Cellular
Photo Credit: © Quest/Science Photo Library/Photo Researchers, Inc.
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2. The Discovery of the Cell
What is the cell theory?
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3. The Discovery of the Cell
The cell theory states:
All living things are composed of cells.
Cells are the basic units of structure and function in living things.
New cells are produced from existing cells.
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Exploring the Cell
Electron Microscopes
Electron microscopes reveal details 1000 times smaller than those visible in light microscopes.
Electron microscopy can be used to visualize only nonliving, preserved cells and tissues.
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Exploring the Cell
Transmission electron microscopes (TEMs)
Used to study cell structures and large protein molecules
Specimens must be cut into ultra-thin slices
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history
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7. Prokaryotes and Eukaryotes
Cells come in a variety of shapes and sizes.
All cells:
are surrounded by a barrier called a cell membrane.
at some point contain DNA.
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8. Prokaryotes and Eukaryotes
Cells are classified into two categories, depending on whether they contain a nucleus.
The nucleus is a large membrane-enclosed structure that contains the cell's genetic material in the form of DNA.
The nucleus controls many of the cell's activities.
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9. Prokaryotes and Eukaryotes
Eukaryotes are cells that contain nuclei.
Prokaryotes are cells that do not contain nuclei.
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10. Prokaryotes and Eukaryotes
What are the characteristics of prokaryotes and eukaryotes?
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11. Prokaryotes and Eukaryotes
Prokaryotic cells have genetic material that is not contained in a nucleus.
Prokaryotes do not have membrane-bound organelles.
Prokaryotic cells are generally smaller and simpler than eukaryotic cells.
Bacteria are prokaryotes.
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1st single cells
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13. Prokaryotes and Eukaryotes
Eukaryotic cells contain a nucleus in which their genetic material is separated from the rest of the cell.
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14. Prokaryotes and Eukaryotes
Eukaryotic cells are generally larger and more complex than prokaryotic cells.
Eukaryotic cells generally contain dozens of structures and internal membranes.
Many eukaryotic cells are highly specialized.
Plants, animals, fungi, and protists are eukaryotes.
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birth of eukaryotes
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7-1
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7-1
The cell theory states that new cells are produced from
nonliving material.
existing cells.
cytoplasm.
animals.
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7-1
The person who first used the term cell was
Matthias Schleiden.
Lynn Margulis.
Anton van Leeuwenhoek.
Robert Hooke.
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7-1
Electron microscopes are capable of revealing more details than light microscopes because
electron microscopes can be used with live organisms.
light microscopes cannot be used to examine thin tissues.
the wavelengths of electrons are longer than those of light.
the wavelengths of electrons are shorter than those of light.
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7-1
Which organism listed is a prokaryote?
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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22. END OF SECTION

23. Explain the Endosymbiotic Theory

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7-2 Eukaryotic Cell Structure
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25. PRETEST
Cell Rap

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Eukaryotic Cell Structures
Structures within a eukaryotic cell that perform important cellular functions are known as organelles.
Cell biologists divide the eukaryotic cell into two major parts: the nucleus and the cytoplasm.
The Cytoplasm is the portion of the cell outside the nucleus.
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Plant Cell
Ribosome (free)
Mitochondrion
Golgi apparatus
Vacuole
Nucleolus
Nucleus
Smooth endoplasmic reticulum
Cell wall
Chloroplast
Nuclear envelope
Rough endoplasmic reticulum
Ribosome (attached)
Cell membrane
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28. Eukaryotic Cell Structures
Animal Cell
Smooth endoplasmic reticulum
Nucleolus
Nucleus
Nuclear envelope
Ribosome (free)
Cell membrane
Rough endoplasmic reticulum
Ribosome (attached)
Centrioles
Golgi apparatus
Mitochondrion
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29. MAKE FLASHCARDS PICTURE OF ORGANELLE FUNCTION(s) OF ORGANELLE
A PICTURE/DRAWING OF SOMETHING IN LIFE THAT WOULD HAVE THE SAME JOB.
Show examples

30. REMEMBER: ALL CELLS HAVE Cells do not all have the same function.
Cell membrane
Ribosomes
Cytoplasm
Genetic material (usually in the form of DNA)
Cells do not all have the same function.
Prokaryotes are bacterial cells
Eukaryotes are found in all of the other kingdoms – plant, animal, Protista, fungi

31. REMINDER: It is theorized that eukaryotes evolved the various organelles by a large prokaryote cell engulfing (eating) a smaller prokaryote This is called the Endosymbiotic Theory
THE FOLLOWING SLIDES WILL REVIEW THE VARIOUS CELL ORGANELLES.
WRITE DOWN THE NAME AND THE FUNCTION

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Nucleus
What is the function of the nucleus?
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Nucleus
The nucleus is the control center of the cell.
The nucleus contains nearly all the cell's DNA and with it the coded instructions for making proteins and other important molecules.
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Nucleus
The Nucleus
Chromatin
Nuclear envelope
Nucleolus
The nucleus controls most cell processes and contains the hereditary information of DNA. The DNA combines with protein to form chromatin, which is found throughout the nucleus. The small, dense region in the nucleus is the nucleolus.
Nuclear pores
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Ribosomes
What is the function of the ribosomes?
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Ribosomes
One of the most important jobs carried out in the cell is making proteins.
Proteins are assembled on ribosomes.
Ribosomes are small particles of RNA and protein found throughout the cytoplasm.
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37. Endoplasmic Reticulum
What is the function of the endoplasmic reticulum?
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Endoplasmic Reticulum
There are two types of ER—rough and smooth.
Ribosomes
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39. Mitochondria and Chloroplasts
What is the function of the mitochondria?
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Mitochondria 
Nearly all eukaryotic cells contain mitochondria.
Mitochondria convert the chemical energy stored in food into compounds that are more convenient for the cell to use.
Mitochondrion
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What is the function of chloroplasts?
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Chloroplasts 
Plants and some other organisms contain chloroplasts.
Chloroplasts capture energy from sunlight and convert it into chemical energy in a process called photosynthesis.
Chloroplast
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Centrioles are located near the nucleus and help to organize cell division.
Cell Organelle Interactive
Plant and Animal Model Interactive
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44. CELL WALL
Organelle Song

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7-2
In the nucleus of a cell, the DNA is usually visible as
a dense region called the nucleolus.
the nuclear envelope.
granular material called chromatin.
condensed bodies called chloroplasts.
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7-2
Two functions of vacuoles are storing materials and helping to
break down organelles.
assemble proteins.
maintain homeostasis.
make new organelles.
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7-2
Chloroplasts are found in the cells of
plants only.
plants and some other organisms.
all eukaryotes.
most prokaryotes.
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7-2
Which of the following is NOT a function of the Golgi apparatus?
synthesize proteins.
modify proteins.
sort proteins.
package proteins.
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7-2
Which of the following is a function of the cytoskeleton?
manufactures new cell organelles
assists in movement of some cells from one place to another
releases energy in cells
modifies, sorts, and packages proteins
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50. END OF SECTION

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7-3 Cell Boundaries
7-3 Cell Boundaries
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All cells are surrounded by a thin, flexible barrier known as the cell membrane.
Many cells also produce a strong supporting layer around the membrane known as a cell wall.
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Cell Membrane
Cell Membrane
The cell membrane regulates what enters and leaves the cell and also provides protection and support.
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Cell Membrane
The cell membrane regulates what enters and leaves the cell.
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Cell Walls
What is the main function of the cell wall?
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Cell Wall
Cell walls are found in plants, algae, fungi, and many prokaryotes.
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57. Diffusion Through Cell Boundaries
Measuring Concentration 
A solution is a mixture of two or more substances.
The substances dissolved in the solution are called solutes.
The concentration of a solution is the mass of solute in a given volume of solution, or mass/volume.
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58. Diffusion Through Cell Boundaries
What happens during diffusion?
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59. Diffusion Through Cell Boundaries
Particles in a solution tend to move from an area where they are more concentrated to an area where they are less concentrated.
This process is called diffusion.
When the concentration of the solute is the same throughout a system, the system has reached equilibrium.
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When equilibrium is reached, solute particles continue to diffuse across the membrane in both directions.
Diffusion depends upon random particle movements. Therefore, substances diffuse across membranes without requiring the cell to use energy.
Diffusion is the process by which molecules of a substance move from areas of higher concentration to areas of lower concentration. Diffusion does not require the cell to use energy.
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Osmosis
What is osmosis?
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Osmosis
Osmosis
Osmosis is the diffusion of water through a selectively permeable membrane.
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How Osmosis Works
Osmosis is the diffusion of water through a selectively permeable membrane. In the first beaker, water is more concentrated on the right side of the membrane. As a result, the water diffuses (as shown in the second beaker) to the area of lower concentration.
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Water tends to diffuse from a highly concentrated region to a less concentrated region.
If you compare two solutions, three terms can be used to describe the concentrations:
hypertonic (“above strength”).
hypotonic (“below strength”).
isotonic (”same strength”)
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Osmotic Pressure 
Osmosis exerts a pressure known as osmotic pressure on the hypertonic side of a selectively permeable membrane.
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Glucose molecules
Facilitated Diffusion
During facilitated diffusion, molecules, such as glucose, that cannot diffuse across the cell membrane’s lipid bilayer on their own move through protein channels instead.
Protein channel
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Active Transport
Active Transport
Sometimes cells move materials in the opposite direction from which the materials would normally move—that is against a concentration difference. This process is known as active transport.
Active transport requires energy.
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Active Transport
Molecular Transport
In active transport, small molecules and ions are carried across membranes by proteins in the membrane.
Energy use in these systems enables cells to concentrate substances in a particular location, even when diffusion might move them in the opposite direction.
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Molecular Transport
Molecule to be carried
Active Transport
Active transport of particles against a concentration difference requires transport proteins and energy.
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Endocytosis and Exocytosis 
Endocytosis is the process of taking material into the cell.
Two examples of endocytosis are:
phagocytosis
pinocytosis
During exocytosis, materials are forced out of the cell.
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7-3
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7-3
Unlike a cell wall, a cell membrane
is composed of a lipid bilayer.
provides rigid support for the surrounding cell.
allows most small molecules and ions to pass through easily.
is found only in plants, fungi, algae, and many prokaryotes.
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7-3
The concentration of a solution is defined as the
volume of solute in a given mass of solution.
mass of solute in a given volume of solution.
mass of solution in a given volume of solute.
volume of solution in a given mass of solute.
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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
move by diffusion from inside the cell to outside.
remain in high concentration outside the cell.
move by diffusion from outside to inside the cell.
cause water to enter the cell by osmosis.
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7-3
The movement of materials in a cell against a concentration difference is called
facilitated diffusion.
active transport.
osmosis.
diffusion.
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7-3
The process by which molecules diffuse across a membrane through protein channels is called
active transport.
endocytosis.
facilitated diffusion.
osmosis.
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78. END OF SECTION