Chapter 7 Cell Structure and Functions

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Chapter 7Cell Structure and Functions

• CP Biology B

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Chapter Outline

• 7-1 Life is Cellular
• 7-2 Eukaryotic Cell Structure
• 7-3 Cell Boundaries
• 7-4 The Diversity of Cellular Life

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7.1 Microscopes and Scientists

• 1. 1665 Robert Hooke
• used compound microscope to look at cork (dead
  wood)
• called small chambers cells
• 2. 1674 Anton Van Leeuwenhoek used single lens
  microscope saw tiny organisms in pond water

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Microscopes and Scientists

• 3. Mathias Schleiden concluded that plants are
  made of cells (1838)
• 4. Theodore Schwann concluded that animals are
  made of cells (1839)
• 5. Rudolph Virchow stated cells come from
  existing cells (1855)

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The Cell Theory

• 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

• 1. Electron microscopes
• Samples are put in a vacuum must be dead
• Transmission electron microscopes (TEM) beams of
  electrons are
• passed through a thin sample
• Scanning electron microscope (SEM) beam of
  electrons move over the surface of a sample

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Prokaryotes and Eukaryotes

• 1. All cells have a cell membrane and contain DNA
• 2. nucleus a large structure that contains the
  cells genetic material in the form of DNA
• 3. Prokaryotes cells that do not contain a
  nucleus, but does contain DNA
• Small and simple cells
• Bacteria are prokaryotes

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Prokaryotes and Eukaryotes
Cell membrane

• 4. Eukaryotes cells that contain a nucleus
• Large and complex cells Highly specialized
• Can be unicellular (one celled organism) or
  multicellular
• Plants, animals, fungi and protists are
  eukaryotes

Prokaryotic Cell
Eukaryotic Cell
Cytoplasm
Nucleus
Organelles
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Cell Organelles

• Eukaryotic cells contain organelles specialized
  structures that perform functions within the cells

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Cell Organelles
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Cell Organelles
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7.3 Cell Boundaries

• Cell membrane thin flexible barrier that
  regulates what enters and leaves the cell.
• 1. Most cell membranes have a lipid bilayer
• 2. Contain proteins and carbohydrates

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Cell Boundaries
Plant Cell

• Cell Wall provides support and protection
• 1. Present in plants, algae, fungi and many
  prokaryotes
• 2. Cell walls lie outside the cell membrane
• 3. Composed mostly of a carbohydrate called
  cellulose

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Diffusion through boundaries

• 1. concentration mass of solute in a given
  volume of solution
• Ex 12 g salt in 3L water 4g/L
• 2. diffusion is the movement of molecules from an
  area of higher concentration to an area of lower
  concentration
• 3. equilibrium when concentration of solute is
  same throughout area

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Osmosis

• 4. Osmosis diffusion of water across a
  selectively permeable membrane
• Water can move across the membrane, and many
  solutes cannot

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Osmosis

• Terms for concentrations on sides of a membrane
• Isotonic concentration is same on both sides
• Hypertonic concentration of solute is higher on
  the outside of the cell
• Hypotonic concentration of solute is lower on
  the outside of the cell
• Cells are usually near isotonic solutions, so
  that they do not burst

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• 5. Facilitated Diffusion protein gates help
  certain molecules diffuse

Glucose molecules
High Concentration
Cell Membrane
Protein channel
Low Concentration
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Active Transport

• 6. Active transport uses energy to move
  molecules from an area of low concentration to
  high concentration

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• Endocytosis process of taking material into
  cells by forming a pocket of cell membrane
• Phagocytosis surrounding food particles
• Pinocytosis surrounding liquids
• Exocytosis process of releasing materials

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7.4 Unicellular vs. Multicellular

• 1. unicellular organisms one-celled organism
  yeast, volvox aureus
• 2. multicellular organisms
• Cell specialization cells throughout an organism
  can develop in different ways to perform
  different tasks
• Specialized animal cells
• Red blood cells carry oxygen throughout body
• Pancreatic cells many ribosomes to make
  proteins and enzymes for digestion
• Muscle cells overdeveloped cytoskeleton

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Multicellular organisms

• Levels of organization (Individual organism)
• Cells?tissues?organs?organ systems

Muscle cell
Smooth muscle tissue
Stomach
Digestive system