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A View of the Cell: Cell Structure

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Title: A View of the Cell: Cell Structure


1
A View of the CellCell Structure
2
Microscopy
  • the use of microscopes to study cells
  • Different types of microscopes
  • Light microscope
  • Transmission electron microscope
  • Scanning electron microscope

3
Compound light microscopes
  • With light as its energy source, it uses a series
    of lenses to magnify up to 1500X

4
Electron microscope
  • Using a beam of electrons as its energy source,
    it can magnify structures up to 500,000 X their
    actual size

(a pin head)
5
Transmission electron microscope
  • TEM
  • studies cellular interiors

Sample of TEM image
6
Scanning electron microscope
  • SEM
  • studies cellular surfaces

Sample of SEM image
7
The study of cellular structure and function is
called cytology, while the study of cells and
tissues in an organism is called histology.
8
Levels of Organization
  • Atom
  • Molecule
  • Organelles
  • Cell
  • Tissue
  • Organs
  • Systems
  • Organisms

9
The 10 Organ Systems
10
Anton van Leeuwenhoek
  • Mid-1600s
  • Holland
  • Used hand lens microscope to observe pond water
  • Observed microscopic life, called them
    animicules

11
Leeuwenhoek Microscope
12
Robert Hooke
13
Robert Hooke
  • Mid-1600s
  • England
  • Used microscope to observe living tissues
  • Named chambers cells

14
Other Early Discoveries
  • Dutrochet (early 1800s) first to suggest parts
    of all organisms are made of cells
  • Brown in 1831 was the first to realize nearly
    ever cell contains a nucleus
  • Dujardin (mid 1800s) used the term sarcode to
    describe protoplasm

15
German cell biologists
1830s Matthias Schleidan concluded all plants
made from cells
1830s Theodor Schwann concluded that all
animals made from cells
16
Rudolph Virchow
  • 1855
  • Germany
  • New cells can only be produced from existing
    cells, confirmed by French scientist Louis Pasteur

17
Cell Theory
  • 1) All organisms are composed of one or more
    cells
  • 2) The cell is the basic unit of structure and
    function of living things
  • 3) All cells come from pre-existing cells

18
To be a cell
  • Plasma membrane (cell membrane) made of 2 layers
    of phospholipids
  • -controls what enters and leaves cell
  • -separates cell from its environment
  • Cytoplasm carbohydrate and water based solution
    that suspends all internal parts of the cell
  • -transports chemical substances in the cell
  • - within the cell, but outside the nucleus

19
To be a cell
  • Ribosomes tiny round bodies that produce
    proteins
  • DNA genetic material made of nucleic acids
  • a) chromatin mass of fibers scattered
  • through the nucleus (thread-like)
  • b) chromosomes compact chromatin
  • -direct store instructions for all
    cell
  • functions
  • -control inheritance of traits

20
Two types of cells
  • Prokaryote bacteria, archaebacteria
  • Eukaryote protists, fungi, plants, animals

21
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22
Prokaryotic cell
  • No nucleus
  • No membrane bound organelles
  • Small
  • Simple
  • Plasma membrane, ribosomes, cytoplasm, DNA

23
Prokaryotic cell
  • Capsule durable outer covering that some
    bacteria have for protection against water,
    acids, and viruses
  • Flagella movement
  • Cell wall protective layer around plasma
    membrane
  • Pili anchoring and DNA exchange

24
Eukaryote
  • More complex
  • 4 basic components organelles
  • Organelles small structures that carry out
    specialized functions within a cell
  • Many variations

25
Plasma Membrane
  • A flexible boundary between the cell and its
    environment maintains a balance of nutrients, etc
  • Selective permeability
  • A process in which a membrane allows some
    molecules to pass through while keeping others
    out

26
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27
Structure of the Plasma membrane
  • Phospholipids
  • A double layer that creates water-soluble
    outsides surrounding water insoluble insides
  • TransporProteins
  • Span the entire membrane to regulate which
    molecules enter and which leave

28
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29
Eukaryotic Cell Structures
30
Nucleus ? cell control
  • Chromatin
  • Strands of genetic material (DNA) that contains
    the directions for making proteins. Forms
    chromosomes
  • Nucleolus
  • A prominent body within the nucleus, produces
    granules rich in RNA, each granule will become
    part of a ribosome
  • Nuclear Envelope
  • Surrounds the nucleus to keep chromatin and
    nucleolus in, while allowing RNA and proteins to
    exit

31
Cytoplasmic Organelles
  • Endoplasmic reticulum (Smooth and Rough)
  • network of interconnected membranes (ER),
    storage, separation, and transport of substances
    made within the cell
  • Smooth no ribosomes
  • Rough dotted with ribosomes
  • Ribosomes
  • Free or bound to the ER, they carry out protein
    synthesis from amino acids

32
Cytoplasmic Organelles
  • Golgi apparatus
  • A flattened stack of membranes that packages
    proteins into vesicles to be secreted by the cell
  • Like a Post office or UPS.

33
Cytoplasmic Organelles
  • Vacuoles
  • Membrane-bound compartments for temporary storage
    of materials
  • May be very large in plant cells

34
Cytoplasmic Organelles
  • Lysosomes
  • Small bodies filled with digestive enzymes that
    digest worn-out organelles, food particles, and
    even engulfed bacteria
  • Responsible for the cells recycling of materials

35
Cytoplasmic Organelles
  • Chloroplasts
  • Containing the green pigment, chlorophyll, these
    oval bodies capture light energy and turn it into
    chemical energy (photosynthesis)

36
Cytoplasmic Organelles
  • Mitochondria
  • Rod-shaped organelle with many inner folds, which
    breaks down sugar to release its stored energy
    for cell use (cell respiration)
  • Powerhouse of the cell

37
Cytoplasmic Organelles
  • Cytoskeleton
  • Tiny rods and filaments (called microtubules and
    microfilaments) that form a supporting framework
    for the cell and function in cytoplasmic streaming

38
Cytoplasmic Organelles
  • Centrioles
  • Pairs of clustered microtubules that play an
    important role in cell division

39
Cytoplasmic Organelles
  • Cilia Flagella
  • External microtubules that aid the cell in
    locomotion or feeding

40
Prokaryotic cell
  • No nucleus
  • No membrane bound organelles
  • Small
  • Simple
  • Plasma membrane, ribosomes, cytoplasm, DNA

41
Plant and Animal Cell Similarities
  • Cell membrane that surrounds the cell
  • Cytoplasm
  • Nucleus that houses DNA
  • Ribosomes for protein production
  • Mitochondria that breaks down food and releases
    energy for the cell.
  • Vacuoles for storage of food, water, and waste.
    Plants have one large vacuole and animals have
    many small vacuoles.
  • Endoplasmic Reticulum (ER)
  • Golgi bodies

42
Differences in Plant and Animal Cells
  • Plants contain a cell wall that surrounds the
    cell membrane and provides shape and support.
  • Plants contain chloroplasts for photosynthesis
  • Plant cells have a brick-like shape where as
    animal cells are more spherical.
  • Plants use chloroplasts to store energy in
    glucose.
  • Plants have one large vacuole animals have many
    small vacuoles.
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