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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

Penemuan Sel

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Sel gabus

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, 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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