Topic: The Introduction of Biology Defining of life Classification of living things Ecosystem and human interferences Basic chemistry, the chemistry of organic molecules Darwin evolutions History of cells Cells structures and functions Photosynthesis and cellular respirations

REVIEWS OF PROKARYOTIC EUKARYOTIC

Review of Eukaryotic Cells

Working cell Copyright © 2009 Pearson Education, Inc. LO’ s: Able to EXPLAIN about: - fluid mosaic of phospholipids and proteins - transportation of molecules across membrane - exocytosis and endocytosis

Molecule Movement & Cells Passive Transport Active Transport Endocytosis Exocytosis

Model cecair mozek Model mozek bendalir :Singer and Nicolson o Dua lapisan fosfolipid o Bersifat bendalir i.e tidak pejal o Komponen utama: lipid dan protein

Solving these problems Mechanisms by which cells solve the problem of transporting ions and small molecules across their membranes: 1) Facilitated diffusion Transmembrane proteinsTransmembrane proteins create a water-filled pore through which ions and some small hydrophilic molecules can pass by diffusion. The channels can be opened (or closed) according to the needs of the cell. 2) Active transport 2) Active transport Transmembrane proteins, called transporters, use the energy of ATP to force ions or small molecules through the membrane against their concentration gradient.

Passive Transport No energy required Move due to gradient – differences in concentration, pressure, charge Move to equalize gradient – High moves toward low

Types of Passive Transport Diffusion Osmosis Facilitated diffusion

Diffusion Molecules move to equalize concentration the net movement of a substance (liquid or gas) from an area of higher concentration to one of lower concentration. stops at equilibrium (when the concentrations across a membrane are equal

Osmosis Special form of diffusion Fluid flows from lower solute concentration Often involves movement of water – Into cell – Out of cell

OSMOTIC PRESSURE

Facilitated Diffusion Differentially permeable membrane Channels help molecule or ions move Usually by transport proteins of cells No energy is used

Process of Facilitated Transport Protein binds with molecule Shape of protein changes Molecule moves across membrane

Passive or Active Transport PassiveActive Passive Transport does not require cell energy Active Transport requires cell energy (ATP) Examples: Diffusion, Facilitated diffusion and Osmosis Examples: Carrier mediated active transport, Endocytosis and Exocytosis

Process of Endocytosis Plasma membrane surrounds material Edges of membrane meet Membranes fuse to form vesicle

Forms of Endocytosis Phagocytosis – cell eating Pinocytosis – cell drinking

Exocytosis Reverse of endocytosis Cell discharges material