Cell Membrane

Functions of the Cell Membrane Gives shape Maintain homeostasis Regulates what goes in/out of cell (semi-permeable)

Cell Membrane Components Outside of cell Inside (cytoplasm) Lipid Bilayer Channel Proteins Protein channel Lipid bilayer

Cell Membrane Made of 2 layers of phospholipids Phospho - comes from phosphorus Lipids - fats Bilayer – 2 layers

Parts of Phospholipid Tail (fatty acid) – repels water - hydrophobic Head (phosphate) – attracts water - hydrophilic Tail (fatty acid) – repels water - hydrophobic

Channel Proteins Control what goes in/out of cell

General Terms Concentration Gradient – uneven distribution of particles Turgor pressure – the water pressure in plant cells Plasmolysis – Process where the cell membrane moves away from the cell wall due to water loss.

Passive Transport Movement of molecules that requires no energy (high concentration low concentration) Examples 1. Diffusion – movement from an area of high concentration to an area of lower concentration    2. Osmosis – the diffusion of water 3. Facilitated Diffusion – movement of LARGE molecules through cell membrane via protein channels or carrier proteins

Diffusion vs. Passive Transport Which side shows diffusion? Which side shows passive transport? High Low

What determines movement of WATER? the solute concentration in the solution that surrounds the cell

Isotonic Solutions Found within our bodies

Active Transport Movement of molecules that REQUIRES energy. Why does it require energy? Because there is the movement of molecules against the concentration difference (low  high) concentration

Passive and Active Videos Passive Transport Active Transport

2 Types of Active Transport Endocytosis – taking in material by infolding of cell membrane Phagocytosis – “eating” of large particles; store food in a vacuole Pinocytosis - taking in of liquids

2 Types of Active Transport 2. Exocytosis – cell releases large amounts of material -Label which diagram is endo/exocytosis

Exit Ticket 1. Please describe three types of passive transport. 2. Please compare and contrast endocytosis and exocytosis. 3. How do these types of endocytosis differ: phagocytosis and pinocytosis