Chapter 7: Cell Membrane (plasma membrane)

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Chapter 7 Cell Membrane (plasma membrane)
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Review the Characteristics of Life

• Try to come up with as many characteristics you
  can. Living things
• Reproduce.
• Have genetic material.
• Grow and develop.
• Use materials and energy.
• Respond to their environment.
• Maintain homeostasis.
• Change over time.
• Are made up of units called cells.

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What is a cell?

• Smallest unit of living tissue collected together
  surrounded by a barrier that separates it from
  the surroundings.
• All living things are made up of cells.
• Here is a neat animation of relative size of
  cells and other objects.

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Cell Theory

• 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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Pro versus Eu

• Cells fall into two broad categories, depending
  on whether the contain a nucleus (controls cells
  activities).
• Prokaryotic
• Does not contain
• Eukaryotic
• Does Contain

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Review

• If a cell of an organisms contains a nucleus, the
  organism is a (an)
• A. plant
• B. eukaryote
• C. animal
• D. prokaryote

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Review

• In many cells, the structure that controls the
  cells activities is the
• A. cell membrane
• B. organelle
• C. Nucleolus
• D. Nucleus

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Review the Biomolecules

• Four main biomolecules found in living things
• Proteins
• Various functions throughout cells/organism.
• Lipids
• Fats, steroids, oils. Doesnt mix with water.
• Function store energy.
• Carbohydrates
• Function main source of energy.
• Nucleotides
• Function store genetic information
• DNA or RNA

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Cell Boundaries

• The cell MEMBRANE regulates what enters and
  leaves the cell and also provides protection and
  support.
• All cells have membranes.
• Also phospholipid bilayer

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Cell Membrane
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Cell Membrane

• The cell membrane is made up of two layers called
  the lipid bilayer.
• The heads of the lipids are on the outsides.
• They are hydrophilic (hydro water philic
  loving).
• The tails of the lipids are on the insides.
• They are hydrophobic (phobic fearing/hating)
• Studded throughout the membrane are proteins with
  various functions.

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Lipids

• made of alcohol and carbon
• Tails are fatty acid chains
• Slight movement to allow water and substances to
  pass through membrane (simple diffusion no
  energy)

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Cell Membrane as a mosaic

• Carbohydrate chain (glyco)- act like chemical
  identification cards allowing individual cells to
  identify one another
• Glycoproteins
• Glycolipids
• Proteins channels and pumps help move material
  across the membrane
• Integral protein (channel)
• Peripheral protein
• Lipids bilayer- gives the membrane a flexible
  structure that forms a strong barrier

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Polar vs. Non-polar

• POLAR/NONPOLAR
• Polar means that the substance has positive or
  negative poles. Non-polar does NOT have positive
  or negative poles.
• Polar things like other polar things. Water is
  polar!!!!!!!!!
• Non-polar things like other non-polar things.
  Oil is non-polar!!!!!!
• Selectively permeable- Some molecules can cross
  the membrane without assistance, most cannot.

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Review

• Cell membranes are constructed mainly of
• A. lipid bilayers
• B. protein pumps
• C. carbohydrate gates
• D. free-moving proteins