Cell structure & organisation

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Transcript of Cell structure & organisation

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Identify the main organelles and membranes in the cell.

    Explain the various functions of the different organelles.

    Compare the structure of plant and animal cells. Describe the relationship between structure and

    function as seen in root hair cells, xylem vessels and red blood cells.

    Differentiate between the levels of organisation in an organism.

    Learning Outcomes

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    A light microscope uses light rays to produce images; an electron microscope uses electron beams.

    Magnification: degree to which the image is enlarged.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Resolution: the smallest distance needed for two points to be distinguished.

    1.1 Structure of Cells

    Depth of field: different tissues lie on different planes.

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Preparing slides for use with the light microscope:

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Preparing slides for use with the light microscope:

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Caring for the microscope: When shifting the microscope, hold on to the

    microscope handle with one hand and support the base with the other. Do not swing it around.

    Do not touch the lenses with your fingers and use only lens paper to clean the glass.

    Before keeping the microscope, first rotate the nosepiece to the low power objective, then lower it until it nearly touches the stage.

    Be careful when working with the slides and cover slips.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Prokaryotes do not have a nucleus and are more primitive.

    Eukaryotes like the animal cell (left) and plant cell (right) have a nucleus where the genetic material resides.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 11.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Nucleus Chromosomes are uncoiled chromatin, visible

    during nuclear division. A man has 46 chromosomes (i.e. 23 pairs of

    chromosomes) in all his cells except the sex cells.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Nucleus

    Nucleolus is the most visible part, responsible for formation of ribosomes.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Endoplasmic Recticulum (ER) Extension of the outer layer of nuclear membrane.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Endoplasmic Recticulum (ER)

    Smooth ER: Without ribosomes Responsible for producing lipids and cholesterol. Where harmful substances are detoxified.

    Rough ER: With ribosomes. Where proteins are synthesised.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Golgi Body

    Stack of membrane-enclosed sacs. Modify small vesicles from ER:

    Small vesicles fuse with one side of this complex. Finished products bud off from the opposite face.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Mitochondria

    Double-membraned organelle. Cristae is the inner membrane, thrown into deep

    folds.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Mitochondria

    Energy extracted from sugar molecules is stored in bonds of adenosine tri-phosphate (ATP) molecules.

    Bonds can be easily released with the help of enzymes during respiration.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Vacuole Fluid-filled sacs.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Vacuoles in animal cells are called vesicles; they are temporary and have different functions such as:

    Storing sugars. Transporting products. Containing digestive enzymes

    to digest invading bacteria. Helping the cell expel excess

    water.

    1.1 Structure of CellsVacuole

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Plant cells have a large and relatively permanent central vacuole.

    1.1 Structure of CellsVacuole

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Cytoplasm and Plasma Membrane1.1 Structure of Cells

    The fluid in which all organelles are suspended is known as the cytosol (in blue).

    The plasma membrane (in orange) controls substances entering or leaving the cell.

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Cytoplasm Entire region of the cell between the nucleus

    and the plasma membrane. Includes the organelles, various membrane and

    cytosol.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Plasma Membrane Transfers chemical messages from the outside of the

    cell to the inside. Keeps the cell contents in place. Made of lipids and proteins. Constantly reforms to allow movement of materials

    into and out of the cell.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 11.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 11.1 Structure of CellsCell Wall Only in plant cells. Presence of strong cellulose

    fibrils for reinforcement. Functions:

    Protects the cell from harmful external influences

    Helps the cell keep its shape Prevents the cell from

    absorbing too much water that it bursts.

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 11.1 Structure of CellsCell Wall

    Plasmodesmata are channels that allow small molecules and water molecules to move between plant cells.

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Central Vacuole

    Makes up 90% of the cells volume in a fully grown plant.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Central Vacuole Tonoplast is the membrane enclosing the cell sap

    which is mainly water. Maintains turgidity of the cell. Stores nutrients, wastes, pigments and poisonous

    substances.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Chloroplasts

    Oval or spherical. Found only in plant cells.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    Chloroplasts Give plant cells their green colour. Give petals and fruits their colour. Others do not contain colour but act as centres of

    starch grain storage or storage of oils and proteins.

    1.1 Structure of Cells

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    The cell is the basic unit of all living organisms. All activities of the cell are controlled by

    information stored in the nucleus. Mitochondria in the cell extract energy from

    glucose and store it as ATP molecules. The energy stored in ATP is used by various

    organelles in the cell such as the ribosomes, which use the ATP to produce proteins for cell repair or for export to other parts of the organisms.

  • Cell Structure and Organisation

    T H E M E O N E : P R I N C I P L E S O F B I O L O G Y

    C h a p t e r 1

    The plasma membrane controls the movement of substances into or out of the cell.

    Plant cells are rigid because o