Chapter 3: The Cell Overview

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Chapter 3 The Cell Overview
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Early Contributions

• Robert Hooke - The first person to see cells, he
  was looking at cork and noted that he saw "a
  great many boxes. (1665)
• Anton van Leeuwenhook - Observed living cells in
  pond water, which he called "animalcules" (1673)
• Theodore Schwann - zoologist who observed that
  the tissues of animals had cells (1839)
• Mattias Schleiden - botanist, observed that the
  tissues of plants contained cells (1845)
• Rudolf Virchow - also reported that every living
  thing is made of up vital units, known as cells.
  He also predicted that cells come from other
  cells. (1850)

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Cell Theory

• Every living organism is made of one or more
  cell.
• The cell is the basic unit of structure and
  function. It is the smallest unit that can
  perform life functions.
• All cells arise from pre-existing cells.
• Why is the Cell Theory called a Theory and not a
  Fact?

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Cell Size Limits

• Cells must remain small in size due to the ratio
  of surface area and volume.
• As a cell gets larger, the volume of the cell
  increases more rapidly than the surface area if
  the cell maintains its same shape.
• As the cell increases in size, its surface area
  becomes to small to support its internal
  structures. Oxygen and other important substances
  cannot diffuse fast enough.
• Cells that get too large, may divide.

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Types of Cells

• Prokaryotic Cells
• 1. Prokaryotes are very simple cells.
• 2. They contain only a membrane (sometimes a
  cell wall), cytoplasm and a strand of DNA.
• Prokaryotic cells do not contain a membrane
  bound nucleus.
• 4. Bacteria are prokaryotes.

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• The word "prokaryote" means before the nucleus.

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• Eukaryotic Cells
• Eukaryotic cells are more advanced cells. These
  cells are found in plants, animals, and protists
  (small unicellular "animalcules").
• The eukaryotic cell is composed of 4 main parts
• cell membrane - outer boundary of the cell
• cytoplasm - jelly-like fluid interior of the cell
• nucleus - the "control center" of the cell,
  contains the cell's DNA (chromosomes) nucleolus
  (assembles ribosomes)
• organelles - "little organs" that carry out cell
  functions

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Mitochondria Energy center or "powerhouse" of
the cell. Turns food into
useable energy(ATP) Ribosomes Make
proteins Golgi Apparatus Processes, packages and
secretes proteins Lysosome Contains
digestive enzymes, breaks things down
Endoplasmic Reticulum Transport, "intracellular
highway" Vacuole Stores water or other
substances Chloroplast Uses sunlight to create
food, photosynthesis (only found in plant
cells) Cell Wall Provides additional support
(plant and bacteria cells) Cytoskeleton Allo
ws cell movement, cell division, internal
motion of compartments. (Microtubules,
centrioles, cilia, flagella)
View the Parts
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Animal Cell
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lysosomes
cytoplasm
cilia
centrioles
nucleolus
nucleus
mitochondria
Rough e.r.
Golgi apparatus
Smooth e.r.
microtubules
ribosomes
vesicles
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Plant Cell
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nuclear membrane
nucleus
nucleolus
Rough e.r.
nuclear envelope
Smooth e.r.
Golgi apparatus
central vacuole
vesicle
microtubules
mitochondria
cell membrane
chloroplast
cell wall
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Types of Microscopes

• Light Microscope - the models found in most
  schools, use compound lenses and light to magnify
  objects.
• The lenses bend or refract the light, which makes
  the object beneath them appear closer.
• Stereoscope - this microscope allows for
  binocular (two eyes) viewing of larger specimens.

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• Scanning Electron Microscope - allow scientists
  to view a universe too small to be seen with a
  light microscope, in 3-D.
• SEMs dont use light waves they use electrons
  (negatively charged electrical particles) to
  magnify objects up to two million times.

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• Transmission Electron Microscope - also uses
  electrons, but instead of scanning the surface
  (as with SEM's) electrons are passed through very
  thin specimens.

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Magnification

• Your microscope has 3 magnifications Low,
  Medium, and High.
• Each objective will have written the
  magnification.
• In addition to this, the ocular lens (eyepiece)
  has a magnification.

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total magnification ocular x objective
Microscope Quiz!
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Chapter 4 Movement Across Cell
Membrane
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A. Diffusion

• 1. Diffusion - the process by which molecules
  spread from areas of high concentration, to areas
  of low concentration.
• 2. Equilibrium - when the molecules are even
  throughout a space.
• 3. Concentration gradient - a difference between
  concentrations in a space.

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Diffusion

• What happens to the particles?
• Ex perfume, food coloring in water, etc.

Diffusion Animation
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B. Osmosis

• 1. Selectively Permeable - membranes that allow
  some things through/ the cell membrane is
  selectively permeable/ water and oxygen move
  freely across the cell's membrane by diffusion.
• 2. Osmosis - the diffusion of water (across a
  membrane)

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Osmosis

• 3. Water will move in the direction where there
  is a high concentration of solute (and hence a
  lower concentration of water).

Osmosis Animation
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• 4. Salt is a solute, when it is concentrated
  inside or outside the cell, it will draw the
  water in its direction. This is also why you get
  thirsty after eating something salty.

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C. Types of Solutions

• 1. If the concentration of solute (salt) is
  equal on both sides, the water will move back in
  forth but it won't have any result on the overall
  amount of water on either side.
• a. "ISO" means the same.

Click Me!
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• 2. The word "HYPO" means less less solute
  (salt) molecules outside the cell means water
  will move into the cell.
• a. Cells will gain water and grow larger.
• b. Plant cells central vacuoles fill so plant
  becomes stiff rigid/ cell wall keeps the plant
  from bursting
• c. Animal cells have danger of bursting/ have
  CONTRACTILE VACUOLES organelles to pump water out
  of the cell to prevent this.

Click Me!
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• 3. The word "HYPER" means more solute (salt)
  molecules outside the cell, which causes the
  water to move in that direction.
• a. Plant cells the central vacuole loses water
  and the cells shrink, causing wilting.
• b. Animal cells the cells also shrink.
• c. In both cases, the cell may die.

Click Me!
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Elodea before salt water added.
Check it out!
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Elodea after salt water added. What type of
solution is the salt water?
Hypertonic!
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Elodea with water added. What type of solution is
the water?
Hypotonic!
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Elodea with salt water.
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Elodea with salt water.
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D Passive Transport

• No energy is required for the molecules to move
  into or out of the cell.
• Ex Diffusion, osmosis, and facilitated
  diffusion.
• Facilitated diffusion The process in which
  some large molecules cannot cross the plasma
  membrane, and are "helped" across by carrier
  proteins.

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E. Active Transport

• 1. This type of transport requires that the cell
  use energy because substances are moving against
  the concentration gradient.
• 2. Sodium Potassium Pump - the cell pumps out 3
  sodium ions and takes in 2 potassium ions.

Click Me!
And Me!
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F. Vesicle Transport

• 1. Endocytosis - cell takes in large particles
  by engulfing them
• 2. Exocytosis - cell gets rid of particles,
  opposite of endocytosis

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G. Cell Communication

• Signal molecules bind to receptor proteins in
  order to receive messages.
• Three functions of receptor proteins
• Cause change in permeability of receiving cell
  (allows specific ions to cross cell membrane)
• Trigger the formation of second messengers
• Activate enzymes (speed up chemical reactions)

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Secondary Messenger Example
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• Drugs affect the binding of signal molecules to
  receptor proteins.
• Example Beta blockers bind to receptor proteins
  in place of signal molecules, preventing the
  heart rate from increasing too rapidly.

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Chapter 5 Photosynthesis Cellular Respiration
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Energy Flow Through an Ecosystem
First Handout
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ATP (Handouts)
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Chloroplast
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Draw this!
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Pigments

• Pigments absorb different wavelengths of light.
• Chlorophylls absorb red, orange, and blue.
• Reflects green!
• Carotenoids absorb
  blue-greens.
• Reflects orange
  yellow!

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Overview of Photosynthesis
stroma
thylakoid
Stage 1 (Light Reaction) Reactants? Light, H2O,
ADP, NADP Products? O2, ATP, NADPH
Stage 2 (Calvin Cycle) Reactants? CO2, ATP,
NADPH Products? ADP, NADP, carbs
grana
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Photosynthesis

• Process of converting light energy into chemical
  energy.
• Plants need only light energy, CO2, H2O to make
  sugar.
• Photosynthesis takes place in the chloroplasts.
• Overall chemical equation
• 6CO2 6H2O light energy ? C6H12O6 6O2
• (glucose)

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Light Reactions (Handout)
Animation
(hydrolysis)
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Light Reaction

• Light reaction uses H2O light energy absorbed
  by pigments in thylakoid.
• Electrons are excited by light move through
  electron transport chain (ETC) in thylakoid
  membrane.
• Water is split.
• H are formed replace electrons used in ETC.
• Oxygen atoms form oxygen gas released into
  atmosphere.
• ATP is produced by 1st ETC.
• NADPH is produced by 2nd ETC.

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Animation
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Dark Reactions (Calvin Cycle)

• Carbon atoms from CO2 are used to make organic
  compounds (glucose) in which energy is stored.
• Calvin cycle is most common method of carbon
  fixation.
• Uses energy from ATP NADPH from light reaction.
• Makes glucose ? takes 6 cycles to make 1 glucose.
• Produces materials to keep cycle going.
• Occurs in stroma.

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Factors Affecting Photosynthesis

• See Handout

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Photosynthesis Animation
See Handouts
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Overview of Cellular Respiration
See Handout
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Cellular Respiration

• Releases much of the energy in food to make ATP,
  which provides cells with energy to carry out
  life activities.
• The human body uses 1 million molecules of ATP
  per cell per second!
• Overall chemical equation
• 6O2 C6H12O6 ? 6H2O 6CO2 energy (ATP)
• (glucose)

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Glycolysis
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Stage 1 Glycolysis

• Glucose is broken down to pyruvate, producing a
  small amount of ATP NADH.
• Dont need oxygen in glycolysis.
• Pyruvate is then converted to Acetyl Co-A.

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The ETC
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GlycolysisStage 2Anaerobic
Aerobic (w/o O2 no ETC)
(w/ O2 ETC)
Occurs in mitochondria Krebs Cycle (Produces 2
ATP per glucose) ETC (34 ATP per glucose) Total
ATP 36 (2 34) Grand Total 38 (stage
12)
Fermentation Lactic Acid Alcoholic Lactate
Ethanol CO2 Total ATP 2
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X 34
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References

• Cork Cells Flea Pics http//askabiologist.asu.
  edu/research/buildingblocks/rhooke.html
• Cell collage, Animal Cells, Plant Cells,
  Bacterial Cell, Microscope Pic
  www.biologycorner.com
• Labeled Microscope www.sciencespot.com
• Secondary Messenger Pic http//www.du.edu/kinna
  mon/3640/second_messengers/Bear6.23.jpg
• Basic Photosynthesis Pic http//static.howstuffw
  orks.com/gif/irrigation-photosynthesis.gif
• Pigment Spectra Chart http//fig.cox.miami.edu/
  cmallery/150/phts/sf7x4c.jpg
• EM Spectrum Pic http//fig.cox.miami.edu/cmalle
  ry/150/phts/spectra.htm
• Photsynthesis Overview Pic http//tol2mac8.soe.b
  erkeley.edu8081/2679/46577060/Photosynthesis.JPG
  
• ATP Pic http//www.biologycorner.com/bio3/notes_
  ATP.html
• CR Overview Pic http//www.biologycorner.com/bio3
  /notes-respiration.html
• Chloroplast Pic http//www.fw.vt.edu/dendro/fore
  stbiology/photosynthesis.swf