Cell Structure and Function - PowerPoint PPT Presentation

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Cell Structure and Function

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Title: Cell Structure and Function Author: Jerry Cook Last modified by: Elizabeth Cowden Created Date: 1/19/2005 1:28:04 AM Document presentation format – PowerPoint PPT presentation

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Title: Cell Structure and Function


1
Cell Structure and Function
2
Learning Target
  • I can discuss the history and components of the
    cell theory.

3
Cells
  • http//www.youtube.com/watch?vRU5Ymc00S4w

4
Cells
  • A cell is the smallest living unit of life
  • Most are microscopic

5
Discovery of Cells
  • Robert Hooke from England (1665)
  • Observed sliver of cork
  • Saw row of empty boxes
  • Coined the term cell because it reminded him of
    monks cells

6
Discovery of Cells
  • Anton van Leeuwenhoek
  • From Holland
  • Observed tiny moving organisms in pond water
  • Animalcules

7
Cell theory
  • (1838)Theodor Schwann, German biologist
  • (1839) Matthias Schleiden, German botanist
  • all living things are made of cells
  • (1855) Rudolf Virchow
  • all cells come from
  • pre-existing cells

8
Principles of Cell Theory
  • All living things are made of cells
  • Cells are the basic units of structure and
    function in living things.
  • New cells are produced from existing cells.

9
Cell Size
10
Cells Have Large Surface Area-to-Volume Ratio
11
Characteristics of All Cells
  • Cell (Plasma) membrane -- A surrounding
    protective membrane
  • Cytoplasm cell contents in thick fluid
  • Control center with DNA

12
Learning Target
  • I can discuss the history and components of the
    cell theory.

13
Learning Target
  • I can analyze the similarities and differences
    between prokaryotic and eukaryotic cells.

14
Cell Types
  • Prokaryotic
  • Eukaryotic

15
Review
  • What are the characteristics of life?

16
Prokaryotic Cells
  • First cell type on earth
  • Small with simple structure
  • Possess all characteristics of life
  • Cell type of Bacteria and Archaea

17
Prokaryotic Cells
  • No membrane bound nucleus
  • Nucleoid region of genetic material (DNA)
  • Organelles not bound by membranes

18
Eukaryotic Cells
  • Nucleus bound by membrane contains genetic
    material (DNA)
  • Include fungi, protists, plant, and animal cells
  • Possess many organelles

Protozoan
19
Learning Target
  • I can analyze the similarities and differences
    between prokaryotic and eukaryotic cells.

20
Learning Target
  • I can describe the functions of all major cell
    organelles.

21
Composite Animal Cell
22
Composite Plant Cell
23
Cell Structure
  • Eukaryotic cell is divided into two major parts
  • Nucleus
  • Cytoplasm
  • the portion of the cell outside the nucleus
    organelles are suspended in this

24
Nucleus
  • Control center of the cell
  • Found in plant and animal cells
  • Surrounded by a double membrane
  • Contains nearly all cells DNA
  • Chromatin

25
Nuclear Envelope
  • Separates nucleus from rest of cell
  • Double membrane
  • Has nuclear pores
  • to allow movement
  • of materials into
  • and out of the nucleus

26
DNA
  • Hereditary material stored in the nucleus
  • Chromosomes contain the DNA which contain the
    instructions for controlling the cells functions
  • Most of the time the DNA is coiled into chromatin
  • Chromosomes are seen as coiled strands inside the
    nucleus is the genetic material seen in the
    nucleus

27
Nucleolus
  • Found inside the nucleus
  • Most cells have 2 or more
  • Directs synthesis of RNA
  • Produces ribosomes

28
Ribosomes
  • Small particles of RNA and protein
  • Located all over the cell
  • Site of protein synthesis
  • Assembles amino acids into proteins
  • Can be free or attached

29
Endoplasmic Reticulum
  • Helps move substances within cells
  • Network of interconnected membranes
  • Two types
  • Rough endoplasmic reticulum
  • Smooth endoplasmic reticulum

30
Rough Endoplasmic Reticulum
  • Has ribosomes attached to surface
  • Manufacture proteins
  • Not all ribosomes are attached to rough ER. Some
    are free in the cytoplasm
  • May chemically modify proteins from ribosomes

31
Smooth Endoplasmic Reticulum
  • No attached ribosomes
  • Has enzymes that help build molecules
  • Carbohydrates
  • Lipids

32
Golgi Apparatus
  • Involved in synthesis of plant cell wall
  • Modifies, sorts and packages proteins and other
    materials from the ER for storage in the cell or
    for secretion outside of the cell.

33
Golgi Apparatus Function
  • 1. Molecules come in vesicles
  • 2. Vesicles fuse with Golgi membrane
  • 3. Molecules may be modified by Golgi
  • 4. Molecules pinched-off in separate vesicle
  • 5. Vesicle leaves Golgi apparatus
  • 6. Vesicles may combine with plasma membrane to
    secrete contents

34
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35
Lysosomes
  • Contain digestive enzymes
  • Functions
  • Aid in cell renewal
  • Use enzymes to break down
  • food and worn out cell parts
  • Digests invaders

36
Vacuoles
  • Membrane bound storage sacs
  • More common in plants than animals
  • Store
  • Water
  • Food
  • Wastes

37
Mitochondria
  • Have their own DNA
  • Bound by double membrane

38
Mitochondria
  • Produces the energy a cell needs to carry out its
    functions
  • Break down fuel molecules (cellular respiration)
  • Glucose
  • Fatty acids
  • Release energy
  • ATP

39
Chloroplasts
  • Capture energy from the sun and convert it into
    chemical energy
  • Photosynthesis

40
Microfilaments/Microtubules
  • Located all over the cell
  • 3 functions
  • mechanical support
  • anchor organelles
  • help move substances

41
A actin, IF intermediate filament, MT
microtubule
42
Cilia Flagella
  • Provide motility
  • Cilia
  • Short
  • Used to move substances outside human cells
  • Flagella
  • Whip-like extensions
  • Found on sperm cells

43
Cilia Flagella Structure
  • Bundles of microtubules
  • Continuous with plasma membrane

44
Centrioles
  • Pairs of microtubular structures
  • Play a role in cell division

45
Learning Target
  • I can describe the functions of all major cell
    organelles.

46
Learning Target
  • I can explain how the cell membrane controls
    movement of substances both into and out of the
    cell and within the cell.

47
Cell Membrane
  • Also known as the plasma membrane
  • Contains cell contents
  • Double layer of phospholipids proteins
  • Controls what enters or exits the cell

48
Phospholipids
  • Polar
  • Hydrophilic head
  • Hydrophobic tail
  • Interacts with water

49
Cell Walls
  • Found in plants, fungi, many protists
  • Surrounds plasma membrane provides support and
    protection for the cell

50
Cell Wall Differences
  • Plants mostly cellulose
  • Fungi contain chitin

51
Cytoplasm
  • Viscous fluid containing organelles
  • components of cytoplasm
  • Interconnected filaments fibers
  • Fluid cytosol
  • Organelles (not nucleus)
  • Storage substances

52
Learning Target
  • I can explain how the cell membrane controls
    movement of substances both into and out of the
    cell and within the cell.

53
Learning Targets
  • I can describe and contrast these types of cell
    transport osmosis, diffusion, facilitated
    diffusion and active transport.
  • I can predict the effect of osmosis within cells
    based on the type of solution surrounding the
    cell.

54
Movement Across the Plasma Membrane
  • Materials move through the plasma membrane in two
    ways
  • Passive transport
  • Actively transport

55
Passive Transport
  • No energy required
  • Move due to gradient
  • differences in concentration, pressure, charge
  • Move to equalize gradient
  • Materials move from areas of high concentration
    to areas low concentration (downhill)

56
Types of Passive Transport
  • 1. Diffusion
  • 2. Osmosis
  • 3. Facilitated diffusion

57
Diffusion
  • Molecules move to equalize concentration

58
Osmosis
  • Special form of diffusion
  • Fluid flows from lower solute concentration
  • Often involves movement of water
  • Into cell
  • Out of cell

59
Solution Differences Cells
  • solvent solute solution
  • Hypotonic
  • Solutes in cell more than outside
  • Outside solvent will flow into cell
  • Cell will swell
  • Isotonic
  • Solutes equal inside out of cell
  • Hypertonic
  • Solutes greater outside cell
  • Fluid will flow out of cell
  • Cell will shrink

60
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61
Facilitated Diffusion
  • Selectively permeable membrane
  • Channels (are specific) help molecule or ions
    enter or leave the cell
  • Channels usually are transport proteins
  • (aquaporins facilitate the movement of water)
  • No energy is required

62
Process of Facilitated Transport
  • Protein binds with molecule
  • Shape of protein changes
  • Molecule moves across membrane

63
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64
Membrane Proteins
  • 1. Channels or transporters
  • Move molecules in one direction
  • 2. Receptors
  • Recognize certain chemicals

65
Membrane Proteins
  • 3. Glycoproteins
  • Identify cell type
  • 4. Enzymes
  • Catalyze production of substances

66
Active Transport
  • Molecular movement
  • Requires energy (against gradient)
  • Example is sodium-potassium pump

67
Endocytosis
  • Movement of large molecules
  • Particles
  • Organisms
  • Movement is into cells
  • Types of endocytosis
  • bulk-phase (nonspecific)
  • receptor-mediated (specific)

68
Process of Endocytosis
  • Plasma membrane surrounds material
  • Edges of membrane meet
  • Membranes fuse to form vesicle

69
Forms of Endocytosis
  • Phagocytosis cell eating
  • Pinocytosis cell drinking

70
Exocytosis
  • Reverse of endocytosis
  • Cell discharges material

71
Process of Exocytosis
  • Vesicle moves to cell surface
  • Membrane of vesicle fuses
  • Materials expelled

72
End Chapter 5
73
Learning Targets
  • I can describe and contrast these types of cell
    transport osmosis, diffusion, facilitated
    diffusion and active transport.
  • I can predict the effect of osmosis within cells
    based on the type of solution surrounding the
    cell.
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