Cell-structure and Function

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Transcript of Cell-structure and Function

  • 9/9/2012

    1

    Cells: Structure and Function

    Chapter 3

    CytologyThe Study of Cell Structure

    and Function

    Cell Biology

    What is a cell?

    Sel merupakan kesatuan struktural, fungsional, dan herediter yang terkecil dari makhluk hidup

    Penemuan Sel

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    Sel gabus

    Organisme sel tunggal volvox yang hidup di dalam air danau

    Penemuan Sel

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    Cell Theory

    All organisms are composed of one or more cells.

    Cells are the smallest living units of all living organisms.

    Cells arise only by division of a previously existing cell.

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    Teori Sel What are the main cell part?

    Cell Characteristics Genetic material

    single circular molecule of DNA in prokaryotes double helix located in nucleus in eukaryotes

    nuclear envelope (double membrane) Cytoplasm fills cell interior

    sugars, amino acids, proteins - organelles

    Plasma membrane encloses the cell phospholipid bilayer

    Phospholipid

    Membraneproteins

    Membran Sel

    Membran sel (=membran plasma) merupakan lapisan tipis yang mengelilingi sel

    Fungsi : - melindungi bagian dalam sel, - menyokong dan memberi bentuk sel- mengontrol transport material ke

    dalam dan ke luar sel

    Plasma membrane: Fluid Mosaic Model

    Separates the intracellularfrom the extracellularenvironments

    A fluid mosaic model A bilayer of lipids with mobile

    globular proteins

    Membrane lipids make up 90-99% of molecules

    in membrane Phospholipids - 75% of lipids Cholesterol - 20% Glycolipids - 5%

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    Cytoplasm

    All materials inside the cell and outside the nucleus: cytosol (fluid):

    dissolved materials: nutrients, ions, proteins, and waste products

    organelles: structures with specific functions

    Sitoplasma

    Sitoplasma : bagiandalam sel, selainnukleusSebagian besar aktivitas dalam sel terjadi di sitoplasma

    Sitosol : bagian di luarorganel sel

    Bentuk bulat Mengontrol semua

    aktivitas dan reproduksi sel

    Terdapat DNA yang berisi informasi untuk menjalankan aktivitas sel

    Nucleus/Inti Visualizing Cells

    Mengapa sel berukuran kecil?

    Cell Size

    Most cells are relatively small because as size increases, volume increases much more rapidly. longer diffusion time

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    Volume = sisi x sisis x sisiArea permukaan = 6 (sisi x sisi)

    Bentuk Sel Why do cells have different shapes?Different cells have different functions or jobsThe shape and structure of most cells help them to do their jobs

    AmoebaUnicellular organism that lives in waterHave the ability to change shape, use pseudopods to move and get food

    Red Blood CellsCarry oxygenDo not have a nucleus, can easyly bend and fold (flexible)Can fit through very small tubes

    Nerve cellsStore or transfer information, carry message (impulses) from one part of the body to another...long and very thin

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    Ukuran SelSel berukuran sangat kecil. Hanya beberapa tipe sel yang cukup besar untuk dapat dilihat dengan mata telanjang

    Sebagian besar sel berukuran 1-100 m dan hanya dapat dilihat dengan mikroskop.

    Bakteri berdiameter antara 1-10 m.Sel eukariota: 10-100 m.

    Bakteri mikoplasma merupakan sel yang paling kecil yang berdiameter antara 0,1-1 m.

    Organel Sel Organel sel : suatu struktur di dalam

    sitoplasma yang mempunyai tugaskhusus

    Mitokondria Retikulum endoplasma Ribosom Badan Golgi Vakuola Lisosom

    What are othe cell parts?

    Ribosomes

    Ribosomes are RNA-protein complexes composed of two subunits that join and attach to messenger RNA. site of protein synthesis assembled in nucleoli

    Endoplasmic Reticulum

    2 Types:1.Rough ER:

    Rough appearance because it has ribosomes Function: helps make proteins, thats why it

    has ribosomes

    2.Smooth ER: NO ribosomes Function: makes fats or lipids

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    Types of Organelles

    Nonmembranous organelles: no membrane direct contact with cytosol

    Membranous organelles: covered with plasma membrane isolated from cytosol

    MitochondriaA. "Powerhouse of the cell" - cellular

    metabolismB. Structure- outer and inner membranes,

    cristaeC. Have their own DNA

    Mitokondria

    Tempat terjadinya respirasi seluler Tempat dihasilkan energi

    Organelles With DNA

    Mitochondria bounded by exterior and interior membranes interior partitioned by cristae

    Chloroplasts have enclosed internal compartments of

    stacked grana, containing thylakoids found in photosynthetic organisms

    Mitochondria and chloroplasts

    Mempunyai ribosom dan DNA (own prokaryote-like genomes)

    Secara evolusi terbentuk dari bakteri yang diendositosis

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    Chloroplasts

    Chloroplasts are larger and more complex than mitochondria

    Grana closed compartments of stacked membranes

    Thylakoids disc shaped structure light capturing pigment

    Stroma fluid matrix

    Chloroplast Ditemukan pada tanaman Mempunyai membran dalam dan membran luar

    (double membrane) Membran tilakoid internal mengandung klorofil Klorofil menangkap dan merubah energi

    matahari menjadi energi kimia

    Chlorophyll captures light energy andconverts it to chemical energy

    Badan Golgi Suatu struktur seperti kantong yang berlipat-lipat Tempat maturasi protein setelah disintesis di

    retikulum endoplasma

    Lisosom Untuk membersihkan organel yang sudah usang Untuk fagositosis

    Cytoskeleton Network of protein fibers supporting cell shape and

    anchoring organelles Actin filaments

    cell movement Microtubules

    Hollow tubes Facilitate cell movement Centrioles barrel shaped organelles occur in pairs help assemble animal cells microtubules

    Intermediate filaments Stable - dont break down

    Actin

    Microtubules

    Intermediate filaments

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    1. Cellular structure/shape

    2. Movement of cell

    3. Movement of molecules or organelles within cell

    Sitoskeleton: Tubules and filaments Plant Cells

    Central vacuole often found in the center of a plant, and

    serves as a storage facility for water and other materials

    Cell wall primary walls laid down while cell is growing middle lamella glues cells together secondary walls inside the primary cell walls

    after growth

    Vakuola

    Tempat menyimpan sementara (makanan, sisametabolisme, kelebihan air)

    Central Vacuole

    Main function = pressure = presses cell contents against cell wall (plant wilts if vacuole not filled with water)

    Small vacuoles = storage

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    Perbandingan organisme prokaryota dan eukaryota

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