Cell-structure and Function
Transcript of Cell-structure and Function
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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
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Organisme sel tunggal volvox yang hidup di dalam air danau
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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, that’s 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 cell’s microtubules
– Intermediate filaments• Stable - don’t 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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