Moving Cellular Material

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Moving Cellular Material

• Science 7
• Darren Nigh
• Cells Chapter 2
• Lesson 3 and 4

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Cells and Spacesuits

• What do spacesuits and cells have in common?
• They both support life
• Sometimes in difficult
• external environments
• What are some similarities
• and differences?

Produced 1930s
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• Spacesuit Features
• Strong outer material protection from
• 
  space particles
• A jetpack to help astronaut
• move
  about
• A tank of
• compressed provide oxygen
• air

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Cell Features

• Outer membrane to keep harmful
  
  particles out
• Tail-like flagella on help cell move
• outside of some cells
• Tiny openings in cell let oxygen and
• membrane water into cell

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Important Terms

• A solute is a type of molecule dissolved in
  another type of substance that substance is
  called a
• Solution
• A Solvent is a substance that dissolves the solute

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CONCENTRATION

• Concentration refers to how much of some
  substance is present, compared to another
  substance.
• For instance, a high solute concentration has a
  relatively high amount of solute and low amount
  of solvent.

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CONCENTRATION EXAMPLES

• High solute concentration lots of sugar
  dissolved in a relatively small amount of water
• Low solute concentration little sugar dissolved
  in a relatively high amount of water

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Diffusion

• Diffusion is the process by which a solute passes
  through pores in a cell membrane
• Diffusion also occurs within a specific area (no
  membrane) as solute
• travels from one area of
• space to another

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How do particles move?

1. Fill a beaker with tap water
2. Add five drops of food coloring to the water
3. After 10 minutes or so observe what has happened.

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What happens to color dye dropped into a
container of purewater? It disperses
evenly!
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Direction of Diffusion

• Molecules ALWAYS diffuse in both directions at
  once (into and out of a cell)
• Net Flow is ALWAYS from greater concentration to
  lesser concentration

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What direction will molecules diffuse across this
membrane? What is the net flow?
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Diffusion in the air

• Molecules may diffuse through the air
  environment
• Example aromas

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• Diffusion tendencies - the tendency of molecules
  to move from a higher concentration to a lower
  concentration until equilibrium is reached.

Higher concentration on the left
Equal-Fully diffused
Equalizing
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What is Osmosis?

• Osmosis is a form of diffusion.
• It is a passive process because it does not
  require outside energy to start the process.
• It is the movement of water molecules Water
  molecules always flow in both directions at once
  (into and out of a cell)

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How does it Work?

• The cell is a closed structure protected by its
  semi permeable bi-lipid membrane.
• This membrane will allow certain molecules to
  enter or leave the cell.
• Water will enter or leave the cell based upon its
  concentration on either side of the cells
  membrane.
• Always from higher to lower concentrations

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Osmosis Animation
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Osmosis in Plant Cells

• The cell wall of a plant will prevent the cell
  from exploding if placed in a hypertonic
  solution.
• Instead the extra water will push against the
  wall making the cell stiff or turgid.

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Why Salt Water Fish die in Fresh Water.

• The cells of a salt water fish are hypertonic to
  the fresh water that surround them.
• The water will move into the cells causing them
  to swell and lyse.
• The gill and blood cells die, eventually killing
  the fish.

Atlantic Cod
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Why a Fresh Water Fish die in Salt Water.

• The cells of a freshwater fish are hypotonic to
  the salt water that surround them.
• The water will move out of the cells causing them
  to shrink or crenate.
• The gill and blood cells die, eventually killing
  the fish.

Black Crappie
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PASSIVE vs. ACTIVE TRANSPORT

• Diffusion and osmosis are examples of passive
  transport, which occurs without a cell using
  energy.
• Cells can move molecules in the opposite
  direction across a membrane by utilizing energy.
  Substances can move from low concentration to
  high concentration
• This is known as active transport.

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Important Terms

• Passive Transport
• Movement across a membrane without using energy
  through diffusion and osmosis from high to low
  concentration
• Facilitated Diffusion
• Movement through a cell membrane using special
  transport proteins.

Carrier proteins move large molecules across the
membrane
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Exocytosis Endocytosis
For molecules too large to pass through the cell
membrane

Cells need to move large molecules. Molecules
move into the cell through endocytosis and out
of it through exocytosis. Both cases, the cell
membrane encloses the molecule in a pocket,
pinches off the pocket and moves it by active
transport.
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Cell size affects transport.
All materials needed by the cell must move
through the cell membrane. If the ratio of
volume to surface area is too large and the cell
doesnt change shape there will not be enough
membrane area to transport necessary materials
into and out of the cell
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• Cells avoid this problem by one of three
  adaptations
• staying small
• dividing
• changing shape

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Lesson 4

• Cells and Energy

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Some cells capture light energy.

• Plants capture light energy from the sun through
  photosynthesis. This process takes place in plant
  cells that have chloroplasts

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• Plants take water from the soil and carbon
  dioxide from the air. In chloroplasts a pigment
  called chlorophyll absorbs light. The cell uses
  energy to break water into hydrogen and
• oxygen

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• The freed hydrogen and the carbon dioxide from
  the air are combined to make glucose. Most the
  oxygen from water is released into the air.

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All cells release energy

• All plant and animal cells break down glucose for
  energy. In cellular respiration the mitochondria
  in cells convert small glucose molecules into
  usable energy called ATP.
• This process is called Glycolysis

Oxygen is used during Glycolysis for the
releasing of energy for use
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Fermentation

• Fermentation allows cells to release energy
  without oxygen. It releases small amounts of
  energy and can produce either carbon dioxide and
  alcohol or lactic acid.
• When you run out of oxygen while exercising, your
  muscles use fermentation to break down sugar.
  This results in a lactic-acid buildup, which
• makes muscles sore

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Does Fermentation release any material?

1. Add 1 packet of yeast to the empty water bottle.
2. Fill the bottle ¾ full with a sugar solution.
3. Place the balloon tightly around the mouth of the
   bottle.
4. Gently swirl the bottle to mix the yeast and
   sugar solution
5. After 20 minutes, observe the balloon.

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• You are now prepared to begin preparation for the
  Chapter 2 Common Assessment