6.1 All organisms are made of cells

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6.1 All organisms are made of cells
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I. The Cell Theory

• In 1655 Robert Hooke observed compartments in a
  thin slice of cork which he named cells
• In 1700 Anton van Leeuwenhoek had developed light
  microscopes to observe tiny living organisms
  which he named animalcules

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First microscopes
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The Cell Theory

• C. Cell theory is the generalization that all
  living things are composed of cells, and that
  cells are the basic unit of structure and
  function in living things

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II. Microscopes as Windows to Cells

• Light microscopes can magnify objects up to about
  1,000 X
• Electron microscopes can magnify objects up to
  about 1,000,000 X
• C. A photograph of the view taken through a
  microscope is called a micrograph

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Microscopes
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Microscopes

• SEM- scanning electron microscope
• TEM- transmission
• Both must use preserved specimens.

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Microscopes
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III. An Overview of Animal and Plant Cells

• Each part of a cell with a specific job to do is
  called an organelle
• B. The plasma membrane defines the boundary of
  the cell and regulates traffic in and out of the
  cell

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Overview of animal and plant

• The nucleus stores the genetic material of the
  cell
• D. The region of the cell between the nucleus and
  the plasma membrane is called the cytoplasm

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Animal Cell
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Animal Cell
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Plant cell
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Plant cell
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IV. Two Major Classes of Cells

• A prokaryotic cell lacks a nucleus and most other
  organelles
• B. A eukaryotic cell has a membrane bound nucleus
  and organelles

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Animal v. Plants
Animal Plant
Plasma membrane Membrane and cell wall
Mitochondria Mitochondria and chloroplast
Cytoplasm, nucleus Both
Most organelles Most organelles
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Eukaryotic v. Prokaryotic
Eukaryotic Prokaryotic
Nucleus No nucleus
Plants and animals Bacteria
Cytoplasm Cytoplasm
Organelles Lacks organelles

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6.2 Membranes organize a cells activities
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I. Membrane Structure

• Membranes regulate the transport of substances
  across it
• Membranes are composed mostly of proteins and
  phospholipids

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Membrane structure

• The phospholipids form a two-layer sandwich
  called a phospholipid bilayer which surrounds
  the organelle or cell
• D. The membranes are fluid-like rather than
  sheets of molecules locked rigidly into place

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Plasma membrane
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Plasma membrane
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II. The Many Functions of Membrane Proteins

• Many types of proteins are embedded in the
  membranes phospholipid bilayer
• B. Some proteins carry out some of the cells
  important chemical reactions, others helps cell
  communicate and recognize each other, other
  proteins move substances like sugar and water
  across the membrane

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Functions of Membrane Proteins
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6.3 Membranes regulate the traffic of molecules
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I. Diffusion

• Diffusion is the net movement of the particles of
  a substance from where they are more concentrated
  to where they are less concentrated
• B. Equilibrium is reached when the movement of
  particles in one direction is equal to the number
  of particles moving in the other

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Diffusion
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II. Passive Transport

1. A selectively permeable membrane allows some
   substances to cross the membrane more easily than
   others and blocks the passage of some substances
   altogether

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Passive transport

• Diffusion across a membrane is called passive
  transport because no energy is expended by the
  cell, only the random motion of molecules is
  required to move them across
• C. Facilitated diffusion is when transport
  proteins provide a pathway for certain molecules
  to pass

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Passive transport

• Carbon dioxide, oxygen- nonpolar
• Water, glucose - polar molecules

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III. Osmosis

• The passive transport of water across a
  selectively permeable membrane is called osmosis
• A solution with a higher concentration of solute
  is called hypertonic hyper above
• C. A solution with a lower concentration of
  solute is called hypotonic hypo below

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III. Osmosis

• D. A solution that has an equal concentration of
  solute is called isotonic iso equal
• When an animal cell is placed in a hypotonic
  solution it swells
• - When an animal cell is placed in a hypertonic
  solution it shrinks

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Osmosis
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IV. Active Transport

• When a cell expends energy to move molecules or
  ions across a membrane it is called active
  transport
• B. A specific transport protein pumps a solute
  across a membrane, usually in the opposite
  direction it travels in diffusion

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Active Transport

• Sodium / potassium pump

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V. Transport of Large Molecules

1. Large molecules have to be packed into vesicles,
   which are small membrane sacs that specialize in
   moving products into, out of and within a cell

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Transport of large molecules

• When a cell exports its protein products, a
  vesicle fuses with the plasma membrane and spills
  its contents outside the cell-a process called
  exocytosis
• The reverse process, endocytosis, takes materials
  into the cell within vesicles that bud inward
  from the plasma membrane

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Transport of large molecules
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6.4 The cell builds a diversity of products
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I. Structure and Function of the Nucleus

• A. The nucleus in a cell contains DNA which
  controls all of the activities inside the cell
• B. The nucleus is surrounded by the nuclear
  envelope which has hole in it which allow
  substances to pass in and out of the nucleus
• C. Inside the nucleus is the nucleolus which
  contains parts necessary to make ribosomes

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nucleus
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II. Ribosomes

• DNA codes for the production of proteins which
  are made in the ribosomes
• B. The ribosomes are either bound to the surface
  of the endoplasmic reticulum or suspended in the
  cytoplasm

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III. The Endoplasmic Reticulum

• The endoplasmic reticulum is an extensive network
  of membranes which functions as the main
  manufacturing and transportation facility in the
  cell
• 1. Rough ER-The rough ER has ribosomes which
  insert proteins right into or through the ER
  membrane or packaged in vesicles and transported
  outside the cell

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Endoplasmic Reticulum

• 2. Smooth ER-The smooth ER lacks ribosomes but
  enzymes in the smooth ER allow it to make lipid
  molecules

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IV. The Golgi Apparatus

• A. The golgi apparatus receives products from the
  ER and modifies, stores and routes proteins and
  other products to their final destination
• B. This organelle is analogous to a processing a
  shipping center of the cell

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V. Vacuoles

• The cytoplasm has large, membrane bound sacs
  called vacuoles
• B. Some vacuoles contain undigested nutrients,
  some pump out excess water that diffuses into a
  cell, others store chemicals that contribute to
  cell growth

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VI. Lysosomes

• Membrane bound sacs called lysosomes contain
  digestive enzymes that can break down such
  molecules like proteins, nucleic acids and
  polysaccharides
• B. Lysosomes will digest food, destroy bacteria
  and digest damaged organelles

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V. Membrane Pathways in a cell

• The membranes inside a cell are transferable from
  one organelle to another
• B. Products may leave a cell without ever
  crossing a membrane

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Membrane pathway in a cell
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6.5 Chloroplasts and mitochondria energize cells
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I. Chloroplasts

• Chloroplasts are the photosynthetic organelles
  found in some cells of plants and algae
• Photosynthesis is a complex, multi-step process
  and the chloroplasts provides the necessary
  organization for the process to take place
• C. Inside the chloroplasts are disks that act as
  the power pack

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chloroplasts

• Chloroplasts are the photosynthetic organelles
  found in some cells of plants and algae
• Photosynthesis is a complex, multi-step process
  and the chloroplasts provides the necessary
  organization for the process to take place
• C. Inside the chloroplasts are disks that act as
  the power pack

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II. Mitochondria

• A. Mitochondria are structures where cellular
  respiration occurs, a process that most organisms
  use to access energy
• ATP is the main energy source for the cell and is
  the end result of cellular respiration
• C. Mitochondria have many infoldings which allows
  for a larger surface area which results in more
  sites for respiration to take place

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mitochondria
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6.6 An internal skeleton supports the cell and
enables movement
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I. The Cytoskeleton

• Straight hollow tubes of proteins that give
  rigidity, shape and organization to a cell are
  called microtubules
• B. Thin solid rods of protein that enable the
  cell to move or change shape are called
  microfilaments

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microtubules microfilaments
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II. Flagella and Cilia

• Flagella are long, thin whip-like structures with
  a core of microtubules that enables the cell to
  move
• B. Cilia are generally shorter and more numerous
  than flagella and move back and forth and moves a
  cell

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flagella and cilia
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III.The Cell as a Coordinated Unit

• It is important to remember that a cells
  organelles do not work alone
• B. The structure of a cell and its organelles
  determine its function and all the individual
  parts must work together

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SA 2 ( 4 pts total)

• Draw a single cell.
• Label the nucleus.
• Is this a plant or animal cell - how do you know?

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Bonus (4 pts)

• Draw one organism.
• Label any visible structures.
• What are the structures used for?