BIOL 1107 1nd Edition Lecture 9 Outline of Last LectureI. Obesity & DietsII. Zero Calorie FoodsIII. Good Carbs vs. Bad CarbsIV. Functions of fat and its importanceOutline of Current Lecture I. Proteins & NutritionII. MembranesIII. Properties of Membrane ProteinsIV. Types of TransportCurrent LectureI. Proteins & NutritionWhat are some good sources of protein? Corn, beans, nuts, eggs, fishComplete proteins: source of protein that contains an adequate proportion of all nineof the essential amino acids necessary for the dietary needs of humans or other animalsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Fake fats & sugars- Aspartame (NutraSweet)- variation of two amino acids, 200 X sweeter than sugar; gets broken down into their amino acids (phenylalanine + aspartame) - Olestra (fatty acids joined to sucrose) - won’t break down into their amino acids; why? You need enzymes to break molecules like these down and the body doesn’t have themo You have to be careful when having supplements like these, because the body doesn’t absorb these alternatives, therefore it is flushed out of the bodyWhat’s the best way to avoid obesity? To limit your total calories, not just your fat caloriesII. MembranesPhospholipids- main component of membrane- Can form micelle, lipid bilayer (which is what the membrane is made of)- Phospholipid heads are not linked and stats; movement occurs- Unsaturated fats: more fluid (animals in colder climates have more unsaturated fats)- Cholesterol: ensure stability; make it less fluid- Nonpolar molecules cross the lipid bilayer easily, because they can squeeze through the hydrophobic core of the membraneQ: Which of the following molecules could move through a phospholipid membrane with the least difficulty? A: O2 (oxygen) because it’s a nonpolar molecule. How do molecules cross?- Hydrophobic: straight through the membrane- Hydrophilic: use transport proteinsIII. Properties of Membrane ProteinsThey are amphipathic (have hydrophobic and hydrophilic properties)How is water likely to pass through cell membrane? Aquaporin (protein channel for water)- 3 billion water molecules per second- Osmosis- diffusion of waterHypertonic (shriveled), isotonic (normal), Hypotonic (lysed)Hypertonic- A solution that has more solutes than in the cellIsolation- A solution that has same concentration of particles as the cellHypotonic- A solution that has less solutes than in the cellIV. Types of TransportPassive: down concentration gradientActive: up concentration
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