Cell Defense: The Plasma Membrane 1. Phospholipids: A phosphate head and two fatty acid tails 2. Phospholipid head: Hydrophilic which means water loving 3. Phospholipid tails: Hydrophobic which means water hating 4. Where do the head and tails face?: The head faces out towards the water and the tails face each other 5. What do you have to put into the membrane in order to stabilize it?: Cholesterol 6. What is another word for selectively permeable?: Semipermeable 7. Semipermeable: The membrane allows some substances to pass through easily, but does not allow others to pass 8. Which two molecules can pass through the membrane? Explain why for each.: Carbon dioxide and oxygen because they are nonpolar and small 9. What three molecules cannot pass through the membrane? Explain why for each.: Sugar because it's large and polar, and both the negative and positive ions because they are a charged substance 10. What does polar mean?: The molecules has partial charges 11. Facilitated diffusion: The process of transporting substances using channel proteins until there were equal amounts of it on both sides of the membrane 12. What does moving from low to high concentration require?: The use of energy to pump substances, which is also known as active transport 13. What does Active transport use?: Carrier proteins and ATP, which is cell energy 14. What does the immune system use carbohydrates for?: To recognize that your cells belong to you and are not viruses, bacteria, or other foreign cells 15. What does the immune system do to foreign invaders?: It kills them 16. What kind of cell kills foreign invaders?: Plasma membrane cells 17. When are channel proteins used?: Passive transport 18. When are carrier proteins used?: Active transport 19. What is osmosis?: Diffusion of ayer across a membrane from an area of higher concentration to an area of lower concentration 20. What is the name of special proteins that let water pass through?: Aquaporins 21. What type of transport are aquaporins?: Passive 1/1