Chapter 3 Movement Of SubstancesAcross The Plasma Membrane 3.1 Movement Across The Plasma Membrane ITeach – Biology Form 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Movement Across The Plasma Membrane Substances required by cell are nutrients and oxygen. Metabolic waste such as carbon dioxide have to be eliminated from cells. Concentration of ion inside cell must be different than outside cell. To maintain these concentrations, cells must allow required substances from surrounding to enter and waste products to leave. Movement of substances in and out of cells is regulated by plasma membrane. Plasma membrane also helps to maintain a constant cellular environment (homeostasis). ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Pergerakan Bahan Merentasi Membran Plasma Bahan yang diperlukan oleh sel adalah nutrien dan oksigen. Bahan buangan metabolik seperti karbon dioksida perlu disingkir daripada sel. Kepekatan di dalam sel mestilah berbeza daripada di luar sel. Untuk mengekalkan kepekatan ini, sel perlu membenarkan bahan yang diperlukan daripada persekitaran untuk memasuki sel dan bahan buangan keluar daripada sel. Pergerakan bahan masuk dan keluar daripada sel dikawal oleh membran plasma. Membran plasma turut membantu mengekalkan persekitaran malar sel (homeostasis). ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane The Structure Of The Plasma Membrane glycoprotein pore phospholipid bilayer carrier protein pore protein non-polar tails phospholipid cholesterol polar head ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Struktur Membran Plasma glikoprotein liang dwilapisan fosfolipid protein pembawa liang protein ekor bukan polar fosfolipid kolesterol kepala polar ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane The Permeability Of The Plasma Membrane Plasma membrane is semi-permeable. Factors that determine whether a molecule can pass through plasma membrane are size and polarity of molecule. Pore proteins allow small water-soluble molecules and ion to pass through. Carrier proteins only allow larger uncharged polar molecules to pass through. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Menghargai Pergerakan Bahan Merentasi Membran Plasma Ketelapan Membran Plasma Membran plasma adalah separa telap. Faktor yang menentukan sesuatu molekul dapat merentasi membran plasma adalah saiz dan kekutuban molekul. Liang protein hanya membenarkan molekul kecil yang larut air dan ion untuk merentasi membran plasma. Protein pembawa hanya membenarkan molekul besar berkutub yang tidak mempunyai cas untuk merentasi membran. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane The Movement Of The Substances • Lipid-soluble molecules: Fatty Substances that acids and glycerol. • Hydrophobic tails can pass through prevent polar • Non-polar molecules : O2 and molecule from CO2 passing through. • Water (polar molecule) can • Large water-soluble pass through Substances that plasma molecules: glucose and amino can’t pass through membrane since acid. its small in size. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Pergerakan Bahan • Molekul lipid terlarut: asid • Ekor hidrofobik Bahan yang dapat lemak dan gliserol. menghalang merentasi membran • Molekul bukan polar: O2 dan molekul berpolar CO2 daripada merentasi membran. • Air (molekul berpolar) dapat Bahan yang tidak • Molekul besar larut air: merentasi dapat merentasi membran kerana glukosa dan asid amino. membran saiznya yang kecil. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Passive Transport • Movement of substances across plasma membrane without using energy. • Example : Gaseous exchange in alveolus and blood capillary. 3 Types Of Passive Transport Simple diffusion Osmosis Facilitated diffusion ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Pengangkutan Pasif • Pergerakan bahan merentasi membran plasma tanpa menggunakan tenaga. • Contoh : Pertukaran gas di dalam alveolus dan kapilari darah. 3 Jenis Pengangkutan Pasif Resapan ringkas Osmosis Resapan berbantu ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Passive Transport Simple Diffusion Net movement of molecules or ion from region of higher concentration to region of lower concentration until an equilibrium is achieve. Dynamic equilibrium is where concentration gradient no longer exists. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Pengangkutan Pasif Resapan Ringkas Pergerakan bersih molekul atau ion daripada kawasan berkepekatan tinggi ke kawasan berkepekatan rendah sehingga keseimbangan dicapai. Keseimbangan dinamik adalah apabila kecerunan kepekatan tidak lagi wujud. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Passive Transport Osmosis : The Diffusion Of Water Water molecules: Solute: • Net movement of water molecules from low solute concentration region to high solute concentration region through semi-permeable membrane. • High water concentration = low concentration of solute in water. • Semi-permeable membrane - permeable to water but not to solutes like sucrose • Essential because cells need adequate water to function well. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Pengangkutan Pasif Osmosis : Resapan Air Molekul air: Bahan larut: • Pergerakan bersih molekul air daripada kawasan berkepekatan bahan laut rendah ke kawasan berkepekatan bahan larut tinggi melalui membran separa telap. • Kepekatan air tinggi = kepekatan bahan larut rendah. • Membran separa telap- Telap kepada air tetapi tidak kepada bahan larut seperti sukrosa. • Penting kerana sel memerlukan air yang cukup untuk berfungsi dengan baik. ITeach – Biology Form 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Passive Transport Facilitated Diffusion • Movement of substances across plasma membrane with aid of carrier proteins and pore proteins following concentration gradient. • Ions, nucleic acids, amino acids and glucose can pass through plasma membrane by facilitated diffusion. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Pengangkutan Pasif Resapan berbantu • Pergerakan bahan merentasi membran plasma dengan bantuan protein pembawa dan liang protein mengikut kecerunan kepekatan. • Ion, asid nukleik, asid amino dan glukosa dapat merentasi membran plasma melalui resapan berbantu. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Facilitated Diffusion - Carrier Protein Outside of cell Glucose Inside of cell Carrier protein binds Carrier protein is then After that, carrier with glucose changes shape to protein assist passage molecules. allow molecules to of another glucose pass through. molecules. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Resapan berbantu– Protein Pembawa Di luar sel Glukosa Di dalam sel Protein pembawa Protein pembawa Selepas itu, protein melekat kepada kemudiannya berubah pembawa membantu molekul glukosa. bentuk untuk laluan molekul glukosa membolehkan molekul yang lain. merentasinya. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Facilitated Diffusion - Pore Protein Pore protein Cell membrane • Pore proteins form pores or channels. • Pores have specified interior characteristics that only have allow specified ions to pass through. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Resapan Berbantu- Liang Protein Liang protein Membran sel • Liang protein membentuk liang atau saluran. • Liang mempunyai ciri dalaman khusus yang hanya membenarkan ion tertentu melaluinya. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Active Transport Movement of molecules or ions against concentration gradient across plasma membrane. Require carrier protein and energy. Energy comes from ATP generated during respiration in mitochondria. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Pengangkutan Aktif Pergerakan molekul atau ion menentang kecerunan kepekatan merentasi membran plasma. Memerlukan protein pembawa dan tenaga. Tenaga didapati daripada ATP yang dihasilkan sewaktu respirasi di dalam mitokondrion. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane The Mechanism Of Active Transport For Sodium Ions Carrier protein Na+ Na+ Na+ Carrier protein has an Carrier protein Solute is moved active site to bind with changes shape when across membrane. molecule and another phosphate group from active site to bind with ATP molecule bind to ATP. it. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Mekanisme Pengangkutan Aktif Bagi Ion Natrium Protein pembawa Na+ Na+ Na+ Protein pembawa Protein pembawa Bahan larut bergerak mempunyai tapak aktif mengubah bentuknya merentasi membran. untuk perlekatan apabila kumpulan dengan molekul dan fosfat daripada tapak aktif lain untuk molekul ATP melekat perlekatan dengan kepadanya. ATP. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Active Transport For Sodium - Potassium Ion In Animal Cells Carrier protein often Concentration of K+ Sodium-potassium called pumps. inside cell is higher pumps help to than concentration maintain concentration outside cell while gradient by pumping concentration of Na+ Na+ out of cell and K+ is vice versa. into cell. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Pengangkutan Aktif Ion Natrium-Kalium Dalam Sel Haiwan Protein pembawa Kepekatan ion K+ di Pam natrium-kalium selalu dipanggil pam. dalam sel adalah lebih membantu tinggi berbanding mengekalkan kepekatan di luar sel kecerunan kepekatan sementara kepekatan dengan mengepam ion Na+ adalah ion Na+ ke luar sel sebaliknya. dan ion K+ ke dalam sel. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Across The Plasma Membrane Comparison Between Passive Transport And Active Transport Passive Transport Active Transport Concentration Against concentration Follow concentration gradient gradient gradient Does not expend energy Energy Need to expend energy Take place in living cells or Condition Take place in living cells non-living cells Active Passive transport transport Diffusion Facilitated diffusion ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Merentasi Membran Plasma Perbezaan Antara Pengangkutan Pasif dan Pengangkutan Aktif Pengangkutan Pasif Pengangkutan Aktif Mengikut kecerunan Kecerunan Melawan kecerunan kepekatan kepekatan kepekatan Tidak menggunakan tenaga Tenaga Perlu menggunakan tenaga Berlaku dalam sel hidup dan Keadaan Berlaku dalam sel hidup sel bukan hidup Pengangkutan Pengangkutan pasif aktif Resapan Resapan berbantu ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane 3.2 Movement Of Substances Across The Plasma Membrane In Everyday Life ITeach – Biology Form 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Of Substances Across The Plasma Membrane In Everyday Life Hypotonic, Hypertonic And Isotonic Solution • Hypotonic solution is when concentration of solution is lower than cell. • Hypertonic solution is solution with higher concentration of solutes than cell. • Isotonic solution is solution with equal solute concentration. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Bahan Merentasi Membran Plasma Dalam Kehidupan Harian Larutan Hipotonik, Hipertonik dan Isotonik • Larutan hipotonik adalah apabila kepekatan larutan kurang daripada sel. • Larutan hipertonik ialah larutan dengan kepekatan yang lebih tinggi berbanding sel. • Larutan isotonik ialah larutan yang mempunyai kepekatan yang sama dengan sel. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Of Substances Across The Plasma Membrane In Everyday Life The Effect Of Hypotonic Solution On Plant Cell On Animal Cell Water enters large centre Water enters cell and vacuole by osmosis causes causes it to swell up and it to expand, swell up and eventually to burst. becomes turgid. Rigid cell wall prevents cell Red blood cells will undergo from bursting. haemolysis. water water molecules molecules vacuole fills with water and expands water water molecules molecules When immersed in distilled water When immersed in distilled water ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Bahan Merentasi Membran Plasma Dalam Kehidupan Harian Kesan Larutan Hipotonik Ke atas sel tumbuhan Ke atas sel haiwan Air memasuki bahagian Air memasuki sel tengah vakuol besar secara menyebabkannya osmosis menyebabkannya membengkak dan akhirnya kembang, bengkak dan pecah. menjadi segah. Sel darah merah akan Dinding sel yang tegar mengalami hemolisis. menghalang sel daripada pecah. molekul air molekul air Vakuol dipenuhi dengan air dan mengembang molekul air molekul air Apabila direndam dalam air suling Apabila direndam dalam air suling ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Of Substances Across The Plasma Membrane In Everyday Life The Effect Of Hypertonic Solution On Plant Cell On Animal Cell Cell undergoes plasmolysis. Red blood cell undergoes crenation Cells become flaccid, Blood cell shrivel and causing the plant to wilt. plasma membrane crinkle Vacuole up. shrinks Cell wall When immersed in 30% sucrose When immersed in 4% sodium solution chloride solution ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Bahan Merentasi Membran Plasma Dalam Kehidupan Harian Kesan Larutan Hipertonik Ke atas Sel Tumbuhan Ke atas Sel Haiwan Sel mengalami plasmolisis Sel darah merah mengalami krenasi Sel menjadi flasid, menyebabkan tumbuhan Sel darah mengecut dan menjadi layu. membran plasma berkedut Dinding Vakuol mengecut sel Apabila direndam di dalam larutan Apabila direndam di dalam larutan sukrosa 30% natrium klorida 4% ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Of Substances Across The Plasma Membrane In Everyday Life The Effect Of Isotonic Solution On Plant Cell On Animal Cell Water diffuses into and out Net movement of water is of cell at equal rate. zero. The cell retains its normal There is no change in the shape. size of cell Water molecules move at the same rate in both directions When immersed in 5% sucrose When immersed in 0.85% sodium solution chloride solution ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Bahan Merentasi Membran Plasma Dalam Kehidupan Harian Kesan Larutan Isotonik Ke atas Sel Tumbuhan Ke atas Sel Haiwan Air masuk dan keluar Pergerakan bersih air daripada sel pada kadar adalah sifar. yang sama. Tiada perubahan pada saiz Sel mengekalkan bentuk sel. asalnya. Molekul air bergerak pada kadar sama di kedua-dua arah Apabila direndam di dalam larutan Apabila direndam di dalam larutan sukrosa 5% natrium klorida 0.85% ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Of Substances Across The Plasma Membrane In Everyday Life Excessive use of fertiliser causes plant to wilt. Potassium nitrate cause soil to turn hypertonic to plant cell when dissolved in soil water. The Phenomenon Of Wilting In Plants Therefore, water diffuses from cell sap into the soil by osmosis and plasmolysis occur. Lack of water in soil also causes plant to wilt. Soil water becomes more concentrated. Plant loses water and cells become plasmolysed. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Bahan Merentasi Membran Plasma Dalam Kehidupan Harian Penggunaan baja berlebihan menyebabkan tumbuhan menjadi layu. Kalium nitrat menyebabkan tanah menjadi hipertonik terhadap sel tumbuhan bila dilarutkan Fenomena Layu dalam air. Pada Tumbuhan Dengan itu, air akan meresap keluar daripada sap sel ke tanah secara osmosis dan plasmolisis berlaku. Kekurangan air dalam tanah juga menyebabkan tumbuhan layu. Air tanah yang tinggal menjadi lebih pekat. Tumbuhan akan kehilangan air dan sel mengalami plasmolisis. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Movement Of Substances Across The Plasma Membrane In Everyday Life The Preservation Of Food • Preservatives cause solution outside the food more hypertonic than the food. • This causes water to move out of the food by osmosis. • Cells in the food substances lose water • These are not conducive to the growth of microorganisms such as bacteria and fungi and will eventually die. • Thus, food can last longer. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Pergerakan Bahan Merentasi Membran Plasma Dalam Kehidupan Harian Pengawetan Makanan • Pengawet menjadikan larutan yang berada di luar makanan lebih hipertonik berbanding makanan itu sendiri. • Ini menyebabkan air meninggalkan makanan secara osmosis. • Sel dalam bahan makanan menjadi terhidrat. • Keadaan ini tidak sesuai untuk pertumbuhan mikroorganisma seperti bakteria serta kulat dan akhirnya mati. • Hasilnya, makanan tahan lebih lama. ITeach – Biologi Tingkatan 4 Chapter 3 Movement Of Substances Across The Plasma Membrane 3.3 Appreciating The Movement Of Substances Across The Plasma Membrane ITeach – Biology Form 4 Chapter 3 Movement Of Substances Across The Plasma Membrane Appreciating The Movement Of Substances Across The Plasma Membrane Appreciating The Movement Of Substances Across The Plasma Membrane Plasma membrane function as a barrier between contents of cell and external environment. Crucial processes in the cells cannot be carried out if there is any flaw in plasma membrane. Proper functioning of plasma membrane is important: - To remove toxic substance - To obtain certain food supplies for energy and raw materials. Good function of plasma membrane can be maintained by taking care of our food and water intake. ITeach – Biology Form 4 Bab 3 Pergerakan Bahan Merentasi Membran Plasma Menghargai Pergerakan Bahan Merentasi Membran Plasma Menghargai Pergerakan Bahan Merentasi Membran Plasma Membran plasma berfungsi sebagai halangan antara kandungan sel dan persekitaran luaran. Proses penting di dalam sel tidak dapat dilakukan sekiranya terdapat sebarang kecacatan pada membran plasma. Membran plasma harus berfungsi dengan baik: - Untuk membuang bahan bertoksik. - Untuk mendapatkan bekalan bahan makanan untuk tenaga. Fungsi membran plasma dapat dikekalkan dengan menjaga pengambilan makanan dan air kita. ITeach – Biologi Tingkatan 4
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