Essential Questions:

1

• Chapter 7 Cell Structure Function
• Georgia Standards
• Analyze the nature of the relationships between
  structures and functions in living cells.
• Explain the role of cell organelles for both
  prokaryotic and eukaryotic cells, including the
  cell membrane, in maintaining homeostasis.

• Essential Questions
• What is the cell theory?
• Why do cells have organelles?
• How do cells maintain constant internal
  conditions?
• How do prokaryotes and eukaryotes differ?

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Warm-up Are all cells alike?

• 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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The Cell Theory

• Anton van Leeuwenhoek (lay-vuhn-hook) (early
  1600s) became one of the first people to use a
  microscope to study nature.
• He was the first person, for example, to see tiny
  living organisms in a drop of water.

• Robert Hooke (1665) used one of the first light
  microscopes to look at thin slices of plant
  tissues, specifically cork.
• They looked like tiny chambers, so he called them
  cells

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The Cell Theory

• The cell theory states the following
• 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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Prokaryotes and Eukaryotes

• Prokaryotes
• Evolved first
• smaller and simpler than eukaryotes.
• cell membranes
• cytoplasm
• NO nuclei
• No membrane-bound organelles
• Ex All bacteria are prokaryotes
• Escherichia coli, which live in your intestines
• Staphylococcus aureus, which can cause skin
  infections.

• Eukaryotes
• Evolved from prokaryotes
• Large
• Multicellular
• Do contain nuclei
• cell membrane
• cytoplasm
• specialized membrane-bound organelles, that
  perform important cellular functions
• Ex All plants, animals, and fungi, and protists.

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Origin of Eukaryotic Cells

• The endosymbiotic theory proposes that eukaryotic
  cells arose from living communities formed by
  prokaryotic organisms.
• Evidence
• First, mitochondria and chloroplasts contain DNA
  similar to bacterial DNA.
• Second, mitochondria and chloroplasts have
  ribosomes whose size and structure closely
  resemble those of bacteria.
• Third, like bacteria, mitochondria and
  chloroplasts reproduce by binary fission when the
  cells containing them divide by mitosis.

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Endosymbiotic theory

• Mitochondria and chloroplasts have many of the
  features of free-living bacteria.
• These similarities provide strong evidence of a
  common ancestry between free-living bacteria and
  the organelles of living eukaryotic cells.
• Play video 17-2

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Prokaryotic and Eukaryotic Cells
Prokaryotic Cell
Nucleus
Eukaryotic Cell
Organelles
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The Structure of a Eubacterium
Section 19-1
Flagella Flagella are whiplike structures used
for movement.
Go to Section
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Checkpoint!!!

• 3. What evidence supports the endosymbiotic
  theory?
• 4. If microscopes had not been invented, do you
  think the cell theory would have been developed?
  Explain your answer.

• 1. What three statements describe the cell
  theory?
• 2. What is the main characteristic that
  distinguishes eukaryotes from prokaryotes?

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Basic Cell Structures (Organelles)

• Organelles isolate cell activities
• Organelles contribute to the specialization of
  eukaryotic cells
• Cells Reproduce, manufacture and release energy,
  and maintain homeostasis

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Basic Cell Structures

• Cell Membrane thin, flexible barrier around the
  cell. Maintains homeostasis
• Cell Wall support and protect cells, while
  allowing them to interact with their surroundings
  (Not in animal cells).
• Nucleus contains the cells genetic material
  (DNA) and controls the cells activities
• Cytoplasm inside the cell membranebut not
  including the nucleus, contains many organelles.

• Despite differences in cell size and shape,
  certain structures are common to most cells.
• Cell membrane
• Cytoplasm

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Cell Wall

• Made of carbohydrates (cellulose) and proteins
• The main function of the cell wall is to provide
  support and protection for the cell.

• Found in many organisms, including plants, algae,
  fungi, and nearly all prokaryotes.
• Animal cells, however, do not contain cell walls.
  
• The cell wall lies outside the cell membrane.
• Most cell walls allow water, oxygen, carbon
  dioxide, and other substances to pass through
  them.      

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Nucleus

• The nucleus controls most cell processes and
  contains the hereditary information of DNA
  (deoxyribonucleic acid).

• Almost all eukaryotic cells, including the plant
  and animal cells contain a nucleus.

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Chromatin and Chromosomes 

• The granular material visible within the nucleus
  is called chromatin.
• It consists of DNA bound to protein.

• Most of the time, chromatin is spread throughout
  the nucleus.
• When a cell divides, however, chromatin condenses
  to form chromosomes (kroh-muh-sohms).

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Nucleolus Nuclear Envelope

•  Most nuclei also contain a small, dense region
  known as the nucleolus (noo-klee-uh-lus).
• The assembly of ribosomes begins. Ribosomes aid
  in the production of proteins within the cell.

• The nucleus is surrounded by a double-membrane
  layer called the nuclear envelope.
• Nuclear pores, which allow material to move into
  and out of the nucleus.
• The nucleus sends a steady stream of RNA and
  other information-carrying molecules to the rest
  of the cell through the nuclear pores.

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• The cytoskeleton is a network of protein
  filaments that helps the cell to maintain its
  shape and is involved in many forms of cell
  movement
• Microtubules
• Microfilaments

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Organelles in the Cytoplasm

• Ribosomes - Proteins are assembled on ribosomes
• small particles made of RNA (ribonucleic acid)
  and protein.

• Endoplasmic Reticulum 
• Transports molecules in cell.
• SER smooth endoplasmic reticulum has no
  ribosomes attached
• RER rough endoplasmic reticulum has ribosomes
  attached

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Organelles in the Cytoplasm

• Golgi Apparatus 
• Proteins produced by the rough endoplasmic
  reticulum move into a stack of membranes called
  the Golgi apparatus.
• Enzymes in the Golgi apparatus attach
  carbohydrates and lipids to proteins.

• Lysosomes  (ly-suh-sohmz) are small organelles
  filled with enzymes.
• break down lipids, carbohydrates, and proteins
  from food
• help break down organelles that have outlived
  their usefulness
• removing debris that might otherwise accumulate
  and clutter up the cell

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Organelles in the Cytoplasm

• Cells often store materials such as water, salts,
  proteins, and carbohydrates in saclike structures
  known as vacuoles (vak-yoo-ohlz).
• Many plant cells have a single large, central
  vacuole filled with liquid.

• Vacuoles are also found in single-celled
  organisms and in animals.
• Smaller vacuoles, especially those involved in
  transporting substances within the cell, are
  often also called vesicles.

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Organelles in the Cytoplasm

• The chloroplasts are found in plants and some
  bacteria and protists.
• Animal and fungal cells do not contain
  chloroplasts.    
• Chloroplasts use the energy from sunlight to make
  energy-rich food molecules in a process known as
  photosynthesis.

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Mitochondria

• The mitochondria are organelles that release
  energy from stored food molecules.    
• Mitochondria are found in nearly all eukaryotic
  cells, including those of plants and algae.
• Mitochondria use energy from food to make
  high-energy compounds that the cell can use to
  power growth, development, and movement in a
  process called cellular respiration.

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Animal Cells
Animal Cell
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Plant Cells
Plant Cell
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Classwork Assignments

• Construct a Venn diagram that compares and
  contrasts eukaryotes and prokaryotes.
• Construct a Venn diagram that compares and
  contrasts the various organelles that exist in
  animal and plant cells.

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Venn Diagrams
Prokaryotes
Eukaryotes
Nucleus Endoplasmic reticulum Golgi
apparatus Lysosomes Vacuoles Mitochondria Cytoskel
eton
Cell membrane Ribosomes Cell wall cytoplasm
Animal Cells
Plant Cells
Cell membrane Cytoplasm Ribosomes Nucleus Endoplas
mic reticulum Golgi apparatus Vacuoles Mitochondri
a Cytoskeleton
Lysosomes Centrioles
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Agenda

• Go to www.cellsalive.com
• Complete handout

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Formative Assessment

• 1. Describe the functions of the endoplasmic
  reticulum, Golgi apparatus, chloroplast, and
  mitochondrion.
• 2. What does the cell wall provide for a cell?
• 3. Describe the role of the nucleus in the cell.
• 4. What are two functions of the cytoskeleton?
• 5.Name two structures that all cells have.
• 6. How is a cell like a factory?