Are All Cells Alike?

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Are All Cells Alike?
Interest Grabber
Section 7-1

• All living things are made up of cells. Some
  organisms are composed of only one cell. Other
  organisms are made up of many cells.
• 1. What are the advantages of a one-celled
  organism?
• 2. What are the advantages of an organism that is
  made up of
• many cells?

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2
Section Outline
Section 7-1

• 71 Life Is Cellular
• A. The Cell Theory
• B. Basic Cell Structures
• C. Prokaryotes and Eukaryotes
• 1. Prokaryotes
• 2. Eukaryotes

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Prokaryotic and Eukaryotic Cells
Section 7-1
Prokaryotic Cell
Nucleus
Eukaryotic Cell
Organelles
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Division of Labor
Interest Grabber
Section 7-2

• A cell is made up of many parts with different
  functions that work together. Similarly, the
  parts of a computer work together to carry out
  different functions.
• Working with a partner, answer the following
  questions.
• 1. What are some of the different parts of a
  computer? What are the functions of these
  computer parts?
• 2. How do the functions of these computer parts
  correspond to the functions of certain cell
  parts?

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5
Section Outline
Section 7-2

• 72 Cell Structures
• A. Cell Wall
• B. Nucleus
• 1. Chromatin and Chromosomes
• 2. Nucleolus
• 3. Nuclear Envelope
• C. Cytoskeleton
• D. Organelles in the Cytoplasm
• 1. Ribosomes
• 2. Endoplasmic Reticulum
• 3. Golgi Apparatus
• 4. Lysosomes
• 5. Vacuoles
• 6. Chloroplasts
• 7. Mitochondria

E. Organelle DNA F. The Cell as a
Factory G. Comparing Cells
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6
Venn Diagrams
Section 7-2
Prokaryotes
Eukaryotes
Nucleus Endoplasmic reticulum Golgi
apparatus Lysosomes Vacuoles Mitochondria Cytoskel
eton
Cell membrane Ribosomes Cell wall
Animal Cells
Plant Cells
Cell membrane Ribosomes Nucleus Endoplasmic
reticulum Golgi apparatus Vacuoles Mitochondria Cy
toskeleton Lysosomes
Centrioles
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Figure 7-5 Plant and Animal Cells
Section 7-2
Plant Cell
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Figure 7-5 Plant and Animal Cells
Section 7-2
Animal Cell
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Figure 7-7 Cytoskeleton
Section 7-2
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Cell Animations

• Cell Video (with music)
• http//aimediaserver.com/studiodaily/videoplayer/?
  srcharvard/harvard.swfwidth640height520
• Cell Video (with narration)
• http//multimedia.mcb.harvard.edu/media.html

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In or Out?
Interest Grabber
Section 7-3

• How is a window screen similar to a cell
  membrane? Read on to find out.
• 1. What are some things that can pass through a
  window screen?
• 2. What are some things that cannot pass through
  a window screen? Why is it important to keep
  these things from moving through the screen?
• 3. The cell is surrounded by a cell membrane,
  which regulates what enters and leaves the cell.
  Why is it important to regulate what moves into
  and out of a cell?

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Section Outline
Section 7-3

• 73 Movement Through the Membrane
• A. Cell Membrane
• B. Diffusion
• C. Osmosis
• 1. How Osmosis Works
• 2. Osmotic Pressure
• D. Facilitated Diffusion
• E. Active Transport

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Facilitated Diffusion
Section 7-3
Glucose molecules
High Concentration
Cell Membrane
No Energy is required!
Protein channel
Low Concentration
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Figure 7-15 The Structure of the Cell Membrane
Section 7-3
Outside of cell
Inside of cell (cytoplasm)
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Figure7-20 Active Transport
Section 7-3
Molecule to be carried
Low Concentration
Cell Membrane
Low ? High
High Concentration
Energy is required!
Molecule being carried
Low Concentration
Cell Membrane
High Concentration
Energy
Energy
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Figure 7-17 Osmosis
Section 7-3
Water molecules
Higher Concentration of Water
Cell membrane
Lower Concentration of Water
Sugar molecules
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Solutions

• Solute What is dissolved
• Solvent Fluid that dissolves the solute (water
  for many solutions)
• Diffusion Movement of molecules from an area of
  high concentration to an area of low
  concentration.
• Osmosis The diffusion of water across a
  selectively permeable membrane.
• HypOtonic o ? O
• Hypertonic o ? e (Imagine the cell shrinks in
  size)
• Isotonic o ? o (Cell size remains the
  same)
• Equilibrium Diffusion will occur until
  equilibrium is reached. This means no net change
  in concentration.

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• A red blood cell is placed into distilled water.
  What will happen to the cell?
• A 4.0 cm piece of potato was placed into a salt
  solution. The potato was later measured at 3.7
  cm. Was the solution hypertonic, hypotonic, or
  isotonic? Explain the result in terms of water
  and solute concentrations.
• Explain why your urine is yellow or clear
  depending on your level of hydration.
• Provide examples of how the process of diffusion
  is important in everyday life.

• Saltwater organisms
• Kidneys
• Digestive System
• Saltwater on plants
• Sweating to moderate temperature

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Cell Structure and Function
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3. Transport

• Cells must be able to move absorbed materials
  around inside the cell.

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Cell Structures

• What is in a cell?
• What do all the parts do?

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Cytoplasm

• All of the materials inside of a cell.
• Not one thing, but many things.

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Organelles

• All of the tiny structures inside the cell that
  carry out life functions.
• Little Organs.

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Cell Wall

• Nonliving, outside of most plant cells.
• Not a part of animal cells.
• Provides protection and support.
• Made of cellulose
• Many substances can pass through it. (oxygen,
  water, carbon dioxide, dissolved materials)

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Cell Membrane

• Outside of an animal cell.
• It is living.
• Controls what goes into and out of the cell.
• Permeable to small molecules.
• Impermeable to larger molecules.
• Selectively Permeable.

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The Nucleus

• Control Center of the Cell
• Large oval structure made of proteins, enzymes,
  and hereditary material.
• Has a nuclear membrane that allows materials to
  pass into and out of the nucleus.

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The Nucleus (continued)

• May contain one or more nucleolus. (These contain
  RNA and protein. They help to make proteins.)

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The Nucleus (the conclusion)

• Contain chromatin material large masses of
  irregular thin threads of DNA, RNA, and proteins.
• These become chromosomes during reproduction.
• Chromosomes hold the genetic information which
  directs cell activities and passes on traits to
  new cells.

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Cytoplasm

• The thick, clear liquid that fills the cell.
• It is always moving.
• All of the other organelles are suspended in the
  cytoplasm.

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Ribosomes

• Small organelles chiefly responsible for making
  proteins.
• Often found on the Endoplasmic Reticulum (ER).

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Endoplasmic Reticulum (ER)

• A canal-like membrane system attached to the cell
  membrane and the nuclear membrane.
• For making proteins and moving them around the
  cell.
• Contains enzymes needed for breaking down food.
• Can be Smooth gt no ribosomes on it or Rough gt
  lots of ribosomes on it.

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LE 6-16-3
Nucleus
Rough ER
Smooth ER
Nuclear envelope
cis Golgi
Transport vesicle
Plasma membrane
trans Golgi
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Mitochondria

• Largest of the organelles.
• Complex and Rod shaped.
• Has an inner and outer membrane.
• The inner membrane has many folds called cristea.
• Filled with a liquid matrix of DNA and ribosomes.
• The Power House of the cell.
• Break down sugars to produce energy for the cell.

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Vacuoles

• Organelles for storing food, enzymes, or other
  materials.
• Temporary Waste Dumping Sites.
• Contractile Vacuoles pump excess water out of the
  cell.

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Lysosomes

• Small, round, enzyme containing organelles.
• They digest food, destroy bacteria, and digest
  the cell when it dies.

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Golgi Apparatus

• Made up of a series of closely stacked, flattened
  sacs.
• They package (wrap) substances to be secreted
  (transported out of) the cell.

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Plastids

• Chloroplasts are tiny, green organelles found
  only in plants.
• Chloroplasts contain chlorophyll, a green pigment
  responsible for helping plants to produce their
  own food.

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Centrioles

• Found in most plant and animal cells.
• There are usually two per cell.
• Move to opposite ends of the cell during
  reproduction.
• Seem to help the cell to divide up its genetic
  material during cell division.