STRUCTURE AND FUNCTION OF THE CELL - PowerPoint PPT Presentation

1 / 36
About This Presentation
Title:

STRUCTURE AND FUNCTION OF THE CELL

Description:

Theory of Spontaneous Generation' The process by which life begins when ethers ... D. The FOUR Plant Organs are ROOTS, STEMS, LEAVES AND FLOWERS. The End ... – PowerPoint PPT presentation

Number of Views:44
Avg rating:3.0/5.0
Slides: 37
Provided by: aspr
Category:
Tags: and | cell | function | structure | the

less

Transcript and Presenter's Notes

Title: STRUCTURE AND FUNCTION OF THE CELL


1
STRUCTURE AND FUNCTION OF THE CELL
  • Developed by Adam F. Sprague

2
Cells
  • Both Living and Nonliving Things are composed of
    molecules made from chemical elements such as
    carbon, hydrogen, oxygen, and nitrogen.  The
    organization of these molecules into Cells is one
    feature that distinguishes Living Things from all
    other matter.  The CELL is the smallest unit of
    matter that CAN Carry on ALL the PROCESSES OF
    LIFE.

3
OBJECTIVES
  • Outline the discoveries that led to the
    development of the Cell Theory. 
  • State the cell theory.  
  • Describe the relationship between cell shape and
    cell function. 
  • Distinguish between prokaryotes and eukaryotes.

4
History
  • 1. In 1665, the English Scientist Robert Hooke
    used a microscope to examine a thin slice of cork
    and described it as consisting of "a great many
    little boxes".  It was after his observation that
    Hook called what he saw "Cells". They looked like
    "little boxes" and reminded him of the small
    rooms in which monks lived, so he called the
    "Cells".
  • 2 . In 1838, German Botanist Matthias Schleiden
    studied a variety of PLANTS and concluded that
    all PLANTS "ARE COMPOSED OF CELLS".
  • 3. The next year, German Zoologist Theodor
    Schwann reported that ANIMALS are also made of
    CELLS and proposed a cellular basis for all life.
  • 4. In 1855, German Physician Rudolf Virchow
    induced that "THE ANIMAL ARISES ONLY FROM AN
    ANIMAL AND THE PLANT ONLY FROM A PLANT" OR " THAT
    CELLS ONLY COME FROM OTHER CELLS".
  • 5.   His statement contradicted the idea that
    life could arise from Nonliving Matter.  "Theory
    of Spontaneous Generation"  The process by which
    life begins when ethers enter nonliving things.

5
CELL THEORY
  • A. All living things are composed of one or more
    cells.
  •     B. Cells are the basic units of structure and
    function in an organism.
  •     C. Cells come only from reproduction of
    existing cells.

6
CELL SHAPE
  • Cells come in a variety of Shapes
  • THE SHAPE OF A CELL DEPENDS ON IT'S FUNCTION
  • ExampleCells of the Nervous System that carry
    information from your toes to your brain are long
    and threadlike.
  • 6.  Blood Cells are shaped like round disk that
    can squeeze through tiny blood vessels.

7
INTERNAL ORGANIZATION
  • 1. Cells contain a variety of Internal Structures
    called ORGANELLES.
  • 2. An organelle is a Cell Component that PERFORMS
    SPECIFIC FUNCTIONS FOR THE CELL.
  • 3. The entire cell is Surrounded by A THIN
    MEMBRANE, called the CELL MEMBRANE
  • 4. A Large Organelle near the Center of the Cell
    is the NUCLEUS.  IT CONTAINS THE CELL'S GENETIC
    INFORMATION AND CONTROLS THE ACTIVITIES OF THE
    CELL.

8
The PRESENCE OR ABSENCE of a NUCLEUS is important
for Classifying Cells.
  • 1. ORGANISMS WHOSE CELL CONTAIN A NUCLEUS AND
    OTHER MEMBRANE-BOUND ORGANELLES ARE CALLED
    EUKARYOTES.
  • 2. ORGANISMS WHOSE CELLS NEVER CONTAIN (OR LACK)
    A NUCLEUS AND OTHER MEMBRANE-BOUND ORGANELLES ARE
    CALLED PROKARYOTES.

9
Differences between
  • - UNICELLULAR ORGANISMS such as bacteria and
    their relatives are Prokaryotes.
  • -   All other organisms are Eukaryotes plants,
    fish, mammals, insects and humans.
  • -  The difference between Prokaryotes and
    Eukaryotes is such an important distinction that
    Prokaryotes are placed in Two Kingdoms, Separate
    from Eukaryotes.

10
PARTS OF THE EUKARYOTIC CELL
  • OBJECTIVES 
  • Describe the structures, composition, and
    function of the cell membrane. 
  • Name the major organelles found in a Eukaryotic
    cell, and describe their function. 
  • Describe the structure and function of the
    nucleus. 
  • Describe three structures characteristic of
    plant cells.

11
THE CELL MEMBRANE
  • All cells, from all organisms, are surrounded by
    a CELL MEMBRANE
  • The Cell Membrane is a thin layer of Lipid and
    Protein that separates the cell's content from
    the world around it
  • The Cell Membrane CONTROLS the ease with which
    substances pass into and out of the cell-some
    substances easily cross the membrane, while
    others cannot cross at all.  For this reason, the
    Cell Membrane is said to be SELECTIVELY PERMEABLE

12
Cell Membranes are made mostly of PHOSPHOLIPID
MOLECULES
  • Phospholipids are a kind of Lipid that consists
    of TWO FATTY ACIDS (TAILS), and PHOSPHATE GROUP
    (HEADS)
  • A Phospholipid Molecule has a  POLAR "Head" and
    Two NONPOLAR "Tails
  • The Phosphate Head is HYDROPHILIC meaning
    "WATERLOVING".   Because of its hydrophilic
    nature, the head of a Phospholipid will orient
    itself so that it is as close as possible to
    water molecules.
  • The Lipid Tails are HYDROPHOBIC meaning
    "WATER-FEARING", the Hydrophobic tails will tend
    to orient themselves away from water
  • When dropped in WATER, PHOSPHOLIPIDS line up on
    the surface with their Phosphate Heads Sticking
    into the Water and Lipid Tails pointing up from
    the surface.

13
MEMBRANE PROTEINS
  • There are many kinds of Proteins in membranes
    they HELP to MOVE Material INTO and OUT of the
    Cell
  • Some Integral Proteins form Channels or Pores
    through which certain substances can pass
  • Other Proteins bind to a substance on one side of
    the Membrane and carry it to the other side of
    the Membrane

14
FLUID MOSAIC MODEL OF CELL MEMBRANES
  • 1.Membranes are FLUID and have the consistency of
    vegetable oil.
  • 2. The Lipids and Proteins of the Cell Membrane
    are always in motion.
  • 3. Phospholipids are able to drift across the
    membrane, changing places with their neighbor.
  • 4. Because the Membrane is FLUID with a MOSAIC of
    Proteins, scientists call the modern view of
    Membrane Structure THE FLUID MOSAIC MODEL

15
CYTOPLASM
  • 1.  EVERYTHING BETWEEN THE CELL MEMBRANE AND THE
    NUCLEUS IS THE CELL'S CYTOPLASM.
  • 2.  CYTOPLASM consists of TWO MAIN COMPONENTS 
    CYTOSOL and ORGANELLES.
  • 3.  CYTOSOL is a jellylike mixture that consists
    MOSTLY OF WATER, along with PROTEINS,
    CARBOHYDRATES, SALTS, MINERALS and ORGANIC
    MOLECULES.
  • 4.  Suspended in the Cytosol are tiny ORGANELLES
    (ORGANS).
  • 5.  ORGANELLES ARE STRUCTURES THAT WORK LIKE
    MINIATURE ORGANS, THEY CARRY OUT SPECIFIC
    FUNCTIONS IN THE CELL.

16
MITOCHONDRIA
  • THE "POWERHOUSE" OF THE CELL
  • Mitochondria are the sites of Chemical Reactions
    that transfer Energy from Organic Compounds to
    ATP.  Energy contain in food is released.
    Converted to ATP.  ATP is the molecule that most
    Cells use as their main Energy Currency
  • Mitochondria are Usually more numerous in Cells
    that have a High Energy Requirement - Your muscle
    cells contain a large number of mitochondria

17
RIBOSOMES
  • Ribosomes are the site of PROTEIN SYNTHESIS
  • They are Most Numerous Organelles in almost all
    cells
  • Some are free in the Cytoplasm others line the
    membranes of ROUGH ENDOPLASMIC RETICULUM

18
ENDOPLASMIC RETICULUM
  • The ER functions Primarily as an Intracellular
    Highway, a path along which molecules move from
    one part of the cell to another
  • Transports materials through the cell
  • ROUGH ER is studded with RIBOSOMES and processes
    PROTEINS to be exported from the cell.
  •     B. SMOOTH ER IS NOT Covered with RIBOSOMES
    and processes LIPIDS and CARBOHYDRATES. The
    Smooth ER is involved in the synthesis of
    steroids in gland cells, the regulation of
    calcium levels in muscle cells, and the breakdown
    of toxic substances by liver cells

19
GOLGI APPARATUS
  • The Golgi Apparatus is the Processing, Packaging
    and Secreting Organelle of the Cell.
  • 2. The Golgi Apparatus is a system of membranes.
    Made of Flattened SAC like Structures called
    CISTERNAE.
  • 3. It works Closely with the ER, the Golgi
    Apparatus modifies proteins for export by the
    cell.

20
LYSOSOMES
  • Lysosomes are the Site of Food Digestion in the
    Cell.
  • 3.  Lysosomes are formed from pieces of the GOLGI
    APPARATUS that break off.
  • 4. Lysosomes are common in the Cells of Animals,
    Fungi, and Protists, But Rare in Plant Cells

21
CYTOSKELETON
  • In Animal Cells, an internal framework called
    CYTOSKELETON maintains the Shape of the Cell
  • The CYTOSKELETON consists of TWO Types of
    structures MICROFILAMENTS AND MICROTUBULES

22
MICROFILAMENTS AND MICROTUBULES
  • MICROFILAMENTS
  • 1. MICROFILAMENTS are NOT HALLOW and have a
    structure that resembles ROPE made of TWO
    TWISTED CHAINS OF PROTEIN called ACTIN.
  • 2. MICROFILAMENTS can CONTRACT, causing movement.
  • 3. Muscle Cells have many microfilaments.
  • MICROTUBULES
  • 1. Microtubules are HALLOW TUBES like plumbing
    pipes. They are the Largest Strands of the
    Cytoskeleton.
  • 2. Microtubules are made of a PROTEIN called
    TUBULIN.
  • 3.  Microtubules have THREE FUNCTIONS
  •     A. To maintain the shape of the cell.
  •     B.  To serve as tracks for organelles to move
    along within the cell.
  •     C.   When the Cell is about to divide,
    bundles of Microtubules known as SPINDLE FIBERS
    come together and extend across the cell to
    assist in the movement of Chromosomes during Cell
    Division

23
CILIA AND FLAGELLA
  • CILIA ARE SHORT HAIRLIKE PROJECTIONS.
  • FLAGELLA ARE LONG WHIPLIKE PROJECTIONS

24
THE NUCLEUS
  • The Nucleus contains DNA, the HEREDITARY MATERIAL
    OF CELLS
  • It maintains its shape with the help of a Protein
    skeleton known as the NUCLEAR MATRIX
  • The nucleus is surrounded by a Double Layer
    Membrane called the NUCLEAR ENVELOPE
  • The DNA is in the form of a long Strand called
    CHROMATIN
  • During Cell Division, Chromatin strands COIL and
    CONDENSES into thick structures called
    CHROMOSOMES.
  • 10. The Chromosomes in the nucleus contain coded
    "BLUEPRINTS" that control all cellular activity
  • The NUCLEOLUS MAKES (syntheisizes) RIBOSOMES,
    WHICH IN TURN, BUILD PROTEINS

25
PLANT CELLS
  • Plant Cells have Three Additional Structures Not
    found in animals cells - CELL WALLS, VACUOLES,
    AND PLASTIDS that are extremely important to
    Plant Function

26
(No Transcript)
27
CELL WALL
  • Fungi such as Mushrooms and Yeast also have Cell
    Walls.  Cell Walls of Fungi are made of CHITIN.
  • 3.  A Cell Wall DOES NOT REPLACE the Cell
    Membrane Cells with WALLS also have a CELL
    MEMBRANE.  Plant Cells are covered by a Rigid
    Cell Wall that lies Outside the Cell Membrane
  • Cell Walls of Plants contain POLYSACCHARIDE (long
    chains) CELLULOSE a complex carbohydrate

28
CELL WALLS ARE OF TWO TYPES
  • A. PRIMARY CELL WALL - While a Plant cell is
    being formed, a primary cell wall develops just
    outside the cell membrane.  As the cell expands
    in length, cellulose and other molecules are
    added, enlarging the cell wall.  When the cell
    reaches full size, a Secondary Cell Wall MAY
    Form.
  •     B. SECONDARY CELL WALL - The secondary cell
    walls forms Between the Primary Cell Wall and the
    Cell Membrane.  The Secondary Cell Wall is Tough
    and Woody, in fact the Secondary Cell Wall is
    what we call WOOD.  One a Secondary Cell Wall
    forms, a plant cell can Grow NO Further.  The
    Cells are Dead.

29
VACUOLES
  • The VACUOLE serves as a STORAGE AREA, and may
    contain stored PROTEINS, IONS, WASTE, OR OTHER
    CELL PRODUCTS
  • VACUOLES of some plants contain Poison that
    discourages animals from eating the plant's
    leaves
  • Cells of Animals and other organisms also MAY
    contain VACUOLES, but they are much smaller and
    are usually involved in FOOD DIGESTION

30
PLASTIDS
  • A THIRD distinguishing feature of PLANT CELLS is
    the presence of STRUCTURES CALLED PLASTIDSTHAT
    MAKE OR STORE FOOD
  • A common kind of PLASTID is the CHLOROPLAST,
    (figure 4-17) an organelle that converts
    SUNLIGHT, CARBON DIOXIDE, AND WATER INTO SUGARS. 
    This process is called PHOTOSYNTHESIS
  • Each Chloroplast encloses a system of Flattened,
    Membranous Sacs called THYLAKOIDS.  It is in the
    Thylakoids that Photosynthesis occurs
  • Chloroplasts are GREEN because they contain
    CHLOROPHYLL, a PIGMENT that ABSORBS ENERGY IN
    SUNLIGHT.  THEY ARE FOUND ONLY IN ALGAE, SUCH AS
    SEAWEED, AND IN GREEN PLANTS.
  • Other PLASTIDS store reddish-orange pigments that
    color fruits, vegetables, flowers, and autumn
    leaves

31
MULTICELLULAR ORGANIZATION
  • In a Unicellular Organism, one cell carries out
    all of the functions of life.  In contrast, most
    cells in a Multicellular Organism are Specialized
    to perform one or a few functions.  Because of
    cell specialization, the cells of Multicellular
    Organisms depend on other cells in the organism
    for their survival.

32
OBJECTIVES 
  • Distinguish between
  • tissue,
  • organs, and
  • organ systems. 

33
TISSUE, ORGANS, AND ORGAN SYSTEMS
  • Cellular Level  The smallest unit of life
    capable of carrying out all the functions of
    living things.
  •     Tissue Level  A group of cells that performs
    a specific function in an organism form the
    TISSUE.
  •     Organ Level  Several different types of
    tissue that function together for a specific
    purpose form an ORGAN.
  •     Organ System Level  Several organs working
    together to perform a function make up an ORGAN
    SYSTEM.  The different organ systems in a
    multicellular organism interact to carry out the
    processes of life

34
(No Transcript)
35
Plants also have Tissue and Organs, although they
are arranged somewhat differently from those of
Animals
  • A. Dermal Tissue System forms the outer layer of
    a plant.
  •     B. Ground Tissue System makes up the bulk of
    roots and stems
  •     C. Vascular Tissue transports water and food
    throughout the plant.
  •     D. The FOUR Plant Organs are ROOTS, STEMS,
    LEAVES AND FLOWERS

36
The End
Write a Comment
User Comments (0)
About PowerShow.com