CELL STRUCTURE AND CELL ORGANISATION · PDF file...

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  • CELL STRUCTURE AND

    CELL ORGANISATION

    CHAPTER 2

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  • Cellular components of

    animal & plant cells

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  • Plant Cells

    Animals Cells

    Cell wall

    Plasma

    membrane

    Vacuole

    Chloroplast

  • Nucleolus

    Nucleus

    Ribosomes

    Vesicles

    Golgi

    Apparatus

    Rough Endoplasmic

    Reticulum

    Plasma

    membrane

    Smooth Endoplasmic

    Reticulum

    Mitochondrion

    LysosomeVacuole

    Centriole

    Cytoplasm

  • Cellular components

    Organelles

    Vacuoles

    Nucleus

    Ribosomes

    Endoplasmic reticulum

    Golgi apparatus

    Lysosomes

    Centrioles (animal cell only)

    Chloroplast (plant cell only)

    Non-organelles

    Plasma membrane

    Cytoplasm

    Cell wall (plant cells only)

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  • Functions

  • Nucleolus

    Nucleus

    Controls all the cell activities

    Separates the genetic material

    from cytoplasm

    Has many pores (nuclear pores) in

    the nuclear membrane for

    materials to enter & exit the nucleus

    Nucleolus is involved in the synthesis

    of ribosome & ribonucleic acid (RNA)

  • Ribosomes

    Are either attached to the ER

    or occur freely in the

    cytoplasm

    Are small ‘protein factories’

    for protein synthesize

  • Synthesizes &

    transports proteins

    made by ribosomes

    Present in large

    amounts in cell that

    makes protein

    E.g. in gut cells that

    manufacture

    digestive enzymes

    Rough Endoplasmic

    Reticulum

  • Receives proteins

    from Rough ER,

    modifies & combines

    the proteins with

    carbohydrates to

    form glyco-protein

    Transport & stores

    lipids

    Golgi Appratus

  • Does not have

    ribosomes

    Synthesizes &

    transport lipids

    Present in large

    amounts in cells that

    make lipids & steroids

    E.g. cell of liver &

    testes

    Smooth Endoplasmi c Reticulum

  • Forms the cell’s

    powerhouse

    Produce adenosine

    triphosphate (ATP),

    which is the energy

    source for the cell

    Mitochondrion

  • Supports & protects

    the cell organelles

    provides a medium

    for all cellular

    metabolic reactions

    Cytoplasm

    medium to produce

    energy, to manufacture

    materials & to store

    minerals

  • Break down macromolecules such as

    proteins, lipids, nucleic acids, polysaccharides

    as well as worn-out organelles

    Lysosome

    Transport undigested

    material to the cell

    membrane for

    removal

  • Are found only in

    animals cells

    Involved in cell

    division (mitosis &

    meiosis)

    Centriole

  • The outer covering of

    the cell

    separates the cell

    from its environment

    and allows materials

    to enter and leave

    the cell

    Plasma membrane

  • Comparing &

    contrasting the structure

    of animal and plant cells

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    Animal cells Plant cell

    Similarities

    Both animal and plant cells have plasma membrane, cytoplasm, nucleus,

    endoplasmic reticulum, Golgi apparatus, ribosomes and mitochondria

    Differences

    Not fixed SHAPE Fixed

    Absent CELL WALL Present

    Absent CHLOROPLAST Present

    If present, are small & scattered throughout the cell

    VACUOLE Has one or a few large vacuole(s) filled with cell sap

    Present LYSOSOME Normally absent

    Present CENTRIOLE Absent

    Carbohydrates are stored in the form of glycogen granules

    FOOD STRORAGE Carbohydrates are stored in the form of starch grains

  • The Density of Certain

    Organelles in Relation to

    Functions of Specific

    Cells

  • What are organelles?

    “little organs”

    Are tiny structures inside a cell that

    perform specific functions for the

    cell

    20

  • What are organelles?

     “3 main functions of organelles:

    a. Carry out their specialized functions:

     E.g. Mitochondria; FUNCTION?

    b. Acts as containers to separate parts of the cell from other

    parts

     E.g. lysosomes

    c. Sites for chemical reaction

     E.g. Chloroplast

  • Relationship between the Density &

    Functions of certain Organelles

    Density of an organelles :

    total number of that particular organelles within

    a cell

    depends on the function of the cell

     to make sure that the cell can perform its specialized functions well

  • Relationship between the Density

    & Functions of certain Organelles

    E.g.

    Cell that specialize in producing enzyme generally have more ER &

    ribosomes to _____________& mitochondria to

    _____________________for its activities

  • The density of mitochondria in

    active cells

     Depends on:

    a) The activity level of an organism

     The more active an organism is, the higher its average density of mitochondria

    b) The specific function of a particular cell

     Cell of active tissues & organs have higher mitochondria densities

  • The density of mitochondria in

    active cells

    Active cells that have high mitochondria densities:

     Sperm cells

     flight muscle cells

     meristemic cells

     liver cells

     kidney cells

  • The density of Chloroplast in the

    Palisade Mesophyll Cells of

    Leaves

    Palisade mesophyll

    of a leaf is :  the main photosynthesis

    tissue

     Packed with chloroplast

    to trap sunlight needed to

    synthesize sugar during

    photosynthesis

     Are arranged in a vertical

    position to optimise

    sunlight trapping

  • Type of cells Function Density of certain

    organelles

    Sperm cells To swim towards either one of the Fallopian tubes to fertilise the ovum

    Mitochondria – are sites of cellular respiration in which energy in the form of ATP is generated through oxidation of food substances such as glucose

    Flight muscle cells

    insects and birds

    Contraction and relaxation of muscles

    provide movement & locomotion

    Mitochondria

    Cells in the meristem Divided actively to produce new cells for growth

    Mitochondria

    Palisade mesophyll cells

    Carry out photosynthesis Chloroplast – contain chlorophyll which trap light energy for photosynthesis

    Goblet cells in the respiratory tract

    Secrete mucus Golgi apparatus

    Liver cells Detoxification of drugs Smooth endoplasmic reticulum

    Pancreatic cells, cells of salivary glands, stomach cells, cells of intestine

    Produce enzyme Rough endoplasmic reticulum and golgi apparatus