Biology Unit 3 Review. Objective 1. Describe the important functions of organic molecules Carbohydrates Lipids Proteins Nucleic acids

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1 Biology Unit 3 Review Name Objective 1. Describe the important functions of organic molecules Carbohydrates Lipids Proteins Nucleic acids 1. What is the difference between organic and inorganic molecules? Organic: Carbon bonded to at least one hydrogen Inorganic: Lacks carbon 2. Give an example of an inorganic molecule. Water 3. Give an example of an organic molecule. Carbohydrates, lipids, nucleic acids, proteins 4. For the following organic molecules, describe what they do in our bodies (why they are important). Don t give examples of the molecules. Tell their functions! Carbohydrates ( 3 ): Energy storage Quick energy supply Structure (cell wall) Lipids (3): Long term energy storage Make up the cell membrane Insulation/Cushion Proteins (6): Structure Chemical Messages Control chemical reactions Transport Muscle contraction Immune system Nucleic Acids (2): Store genetic information (DNA) Transmit genetic information (RNA) Objective 2: Describe why water is important for living organisms 5. List 5 reasons that water is important for living organisms Excellent solvent and suspending medium Participates in chemical reactions Absorbs and releases heat slowly Large amounts of heat needed to evaporate

2 Great lubricant Objective 3: Explain the purpose of cellular transport. 6. What is the purpose of cellular transport? Letting nutrients in and releasing wastes Maintaining correct amounts of water Maintining ion concentrations Letting out cellular products that are needed in other parts of the cell In other words, letting in needed materials and letting out unneeded materials. 7. What part of the cell is involved during transport? The Cell Membrane Objective 4: Define passive transport (Diffusion, Osmosis) 8. What is passive transport? Movement of particles into or out of the cell that does not require the cell s energy 9. What are 2 examples of passive transport? Define each example. Diffusion: is the process by which molecules of a substance move from areas of high concentration to areas of low concentration along a concentration gradient Osmosis: is a special kind of diffusion. It is the process of water moving or diffusing from an area of high concentration to an area of low concentration through a semi-permeable membrane. Objective 5: Describe how diffusion occurs and its importance in cell activity. 10. How are molecular collisions relevant to diffusion? It is always happening randomly, which causes the molecules to spread out through the use of kinetic energy (the energy of motion). Molecular collisions cause diffusion. 11. Describe how diffusion happens. When there is an uneven distribution of molecules, the highly concentrated molecules randomly collide with one another causing the molecules to move to a less concentrated area until equilibrium is reached. 12. How is diffusion important to a cell? It is important because it allows small molecule to enter and leave the cell without using cellular energy Objective 6: Describe how osmosis occurs and its importance in cell activity 13. How is osmosis different than diffusion? Osmosis is a special type of diffusion that just deals with water from areas of high to low concentration across the cell membrane along a concentration gradient. 14. How is osmosis important to a cell?

3 Because our body is made up of mostly water and water plays a major role in maintaining homeostasis, our body needs to maintain an equal balance of water throughout the inside and outside of the cells. Objective 7: Given an example, be able to predict the direction of movement of materials through a membrane. 15. Use the picture below to answer a-f. 93% water 99% water 96% water 98% water 90% water 3% solutes 2% solutes 10% solutes 97% water A B C a. In which drawing(s) will the cell swell in size? B b. In which drawing(s) will the cell shrink in size? A and C c. In which drawing is the concentration gradient the greatest? B d. When will net movement cease to occur? Which drawing will reach that point first? When equilibrium is reached net movement will cease C e. In which drawing will the initial movement of molecules be the fastest? Why? B, because the concentration difference is the greatest, causing a greater concentration gradient. f. What is this process called? Osmosis g. What are 2 ways to speed up this process? Heat Increase concentration gradient (make a larger difference between water concentrations) Objective 8: Define and describe forms of active transport and their importance in cell activity. ( Endocytosis, Exocytosis) 16. What is the purpose of active transport? Why is this necessary? To use the cells energy to move large or charged molecules across the cell membrane. It is necessary to provide our body with needed materials that can t be brought in through diffusion. 17. What are 2 types of active transport? Explain the difference between them. Passage of Materials Using Carrier Proteins: Carrier proteins and energy are used to pump ions and other molecules across the cell membrane, against the concentration gradient. Bulk Movement: Large molecules are moved across the cell membrane by being packaged in large sacs Endocytosis: move large materials and nutrients into the cell

4 Exocytosis: move waste and cellular products out of the cell 18. What structure within the cell membrane assists during active transport? Carrier proteins Objective 9: Compare and contrast active and passive transport. (Examples, Energy required, Concentration gradient) 19. Compare passive and active transport. How are they similar? Both are needed to transport certain molecules into and out of the cell. Both are needed to help maintain homeostasis. 20. Contrast passive and active transport. Explain at least 4 differences. Passive: Active: High to low concentration Low to high and/or high to low Does NOT use cellular energy (only kinetic) Requires cellular energy Small and uncharged molecules Large and/or charged molecules Particles: O 2, CO 2, H 2 O Particles: Proteins, large carbohydrates 21. Liver cells are packed with glucose molecules. What mechanism would be used to transport more glucose into a liver cell? Why would only this mode of transport work? Active Transport Because glucose needs to move against the concentration gradient (from low to high concentration) Objective 10: Describe the structure of the cell membrane and explain its importance in the transport of materials into and out of the cell. (Phospholipid bilayer, Carrier molecules, Cell Membrane) 22. What is the other name for a cell membrane? Phospholipid Bilayer 23. What is the significance of the cell membrane with respect to transport? The structure of the cell membrane is what regulates the molecules that enter and leave the cell. 24. What is the function of the proteins in the cell membrane? To move large or charged particles in or out of the cell. 25. What does semi-permeable mean? Why is this an important characteristic of the cell membrane? Semi-permeable: The cell membrane allows only certain molecules to pass through. It is important in maintaining homeostasis Objective 11: Describe how cellular activity enables an organism to maintain homeostasis. 26. What is the definition of homeostasis? maintaining a stable internal environment 27. Why is it important that cells maintain homeostasis? Cells need stable constant conditions to function properly 28. Explain how the body maintains homeostasis during exercise. Include physiological changes in the body and reasons for these changes in your explanation.

5 Examples: Your cells are using more energy and oxygen while exercising than while at rest. Your breathing rate increases while exercising to get more oxygen into your body to replace the oxygen being used up by your cells. Your heart rate increases to get oxygen and food (energy) to the cells that are using them up during exercising. Exercise (movement) produces heat. You sweat to cool your body down. Objective 12: Explain the structure and function or purpose of an enzyme. 29. What type of organic molecule is an enzyme? protein 30. What is the main function of an enzyme? Speed up chemical reactions ---- lower activation energy 31. Which of the following is likely the name of an enzyme? Hemoglobin Amylase Lymphocyte Leukoblast Why? Amylase, because it ends in ase. 32. What is a substrate? The substance that the enzyme works on or attaches to 33. What is an active site? Spot on the enzyme that the substrate attaches 34. What is catalase? An enzyme that breaks down hydrogen peroxide 35. Explain what enzyme specificity means. One enzyme works on one specific substrate In other words, enzymes can only work on one type of reaction 36. Could catalase break down hydrogen peroxide and lipids? Why or why not? NO! Because of specificity. It may only work on hydrogen peroxide. Objective 13: Describe the effects of ph and temperature on enzyme activity. 37. What does it mean to become denatured? When an enzyme s shape is changed --- no more active site! 38. List several ways that an enzyme can become denatured. Extreme heat Extreme ph (too much acid or base) Poisons Lots of vibration or shaking 39. How do cold temperatures affect enzyme activity? Slows it down (does NOT denature)

6 40. What ph do you think most of your cells would be? Why? ph of 7 because your body is 70% water water has a neutral ph 41. Where in your body do you think the ph would differ from #40? Why? Your stomach, because of your stomach acid 42. Look at the graph below. What temperature does catalase work best at? 37 C Objective 14: Review components of experimental design (see unit 1 objectives for criteria). Hypothesis Procedure Data Table Graph Conclusion 43. Lactase is an enzyme that breaks down lactose, a sugar present in milk, into glucose and galactose. You know that people who cannot digest lactose can use a product that contains lactase to break down the milk sugar. You are curious about the effectiveness of these milk-treatment products. You decide to design an experiment to see the effectiveness of different amounts of the lactase product in breaking down the lactose. You do so by measuring the amount of lactose present after 5 minutes after a certain amount of lactase product was added. PROCEDURE SUMMARY: We put 100 ml of milk in 5 beakers. In beaker 1, we put 0 drops of lactase; beaker 2, 10 drops; beaker 3, 20 drops; beaker 4, 30 drops, beaker 5, 40 drops (about 1 teaspoon the recommended dosage). We then waited 5 minutes and measured the amount of glucose present in each beaker. RESULTS : The average amount of glucose present in 50 ml of milk after using different amounts of lactase product. Amount of Lactase Product (drops) Average Amount of Glucose Present in the Milk after 5 minutes (ml). 0 0 ml 10 2 ml 20 5 ml ml ml 1. What is the enzyme in this experiment? What is the substrate?

7 Lactase is the enzyme. Lactose is the substrate. 2. What is the independent variable in this experiment? Amount of lactase product 3. What is the dependent variable in this experiment? Effectiveness of lactase product 4. How are you measuring the dependent variable? By determining the amount of glucose present in the milk after 5 minutes (the more glucose; the more effective the amount of product) 5. What are the controls? Basis for comparison could be 0 drops of lactase product to see what happens when there is no lactase. Basis of comparison could also be 40 drops of lactase product because that is the normal recommended dose. 6. Using data from the table on the previous page, to design a graph below. Be sure to include appropriate Titles, Labels, and Units!!!! Title: The average amount of glucose present in 50 ml of milk after using different amounts of lactase product. X axis (IV) label: Amount of Lactase Product (drops) Y axis (DV label: Average Amount of Glucose Present in the Milk after 5 minutes (ml)

8 Should have 0,0 labeled on origin (bottom left corner) of graph Should have a line graph data points should be connected.