Travis Miller - Unit 5 Study Guide PDF

Name: _____________________ Block:_________ Date:_________ THE WORKING CELL - UNIT 5 Exercise (Modules 5.1-5.2) Review membrane structure and function by labeling the diagram of the membranes of two adjacent cells in...

Name: _____________________ Block:_________ Date:_________ THE WORKING CELL - UNIT 5 Exercise (Modules 5.1-5.2) Review membrane structure and function by labeling the diagram of the membranes of two adjacent cells in the following image. Starting outside the cells, label a fiber of the extracellular matrix (ECM) and a signaling molecule. Inside the cells, label the cytoplasm and a microfilament of the cytoskeleton. In the membranes, find a phospholipid molecule, a cholesterol molecule, and a glycoprotein. Finally, identify protein molecules carrying out these functions: Cell-cell recognition, enzymatic activity, transport, intercellular junction, signal transduction, receptor, and attachment to the cytoskeleton and ECM. (You will note that this diagram is slightly different from Figure 5.1, so be careful!) Exercise 2 (Modules 5.3-5.9) Review diffusion and the function of cell membranes by matching each of the phrases on the left with the appropriate mechanisms from the list on the right. Two questions require more than one answer. _______ 1. Diffusion across a membrane _______ 2. Moves solute against concentration gradient _______ 3. Any spread of particles from an area of higher concentration to an area of lower concentration _______ 4. Diffusion with the help of a transport protein _______ 5. Three types of endocytosis _______ 6. Engulfing of fluid in membrane vesicles _______ 7. Diffusion of water across a selectively permeable membrane _______ 8. It involves transport molecules that need ATP to function _______ 9. Enables cell to engulf bulk quantities of specific large molecules _______ 10. How oxygen and carbon dioxide enter and leave cells _______ 11. Causes plant cells to become turgid _______ 12. Engulfing of particle or object in membrane vesicle _______ 13. Fusion of membrane-bound vesicle with membrane, and dumping of contents outside the cell _______ 14. How a cell might capture a bacterium _______ 15. Helped by aquaporins _______ 16. Causes cream to mix with coffee _______ 17. Occurs from a hypotonic to a hypertonic solution _______ 18. Two types of passive transport _______ 19. Occurs when the Golgi apparatus exports proteins _______ 20. How a cell maintains a higher K+ concentration and lower Na+ concentration than its surroundings Exercise 3 (Modules 5.4-5.5) Osmosis is an important process that has many effects on living things. Test your understanding of osmosis by predicting in each of the following cases whether water will enter the cell (In) or leave the cell (Out), or whether there will be no net movement of water (None). Assume that the plasma membrane is permeable to water but not solutes. ________ 1. Cell is exposed to a hypertonic solution. ________ 2. Cell is placed in a salt solution whose solute concentration is greater than that of the cell contents ________ 3. Due to disease, the solute concentration of the body fluid outside a cell is less than the solute concentration inside cells. ________ 4. Cell is immersed in an isotonic solution. ________ 5. A single-celled organism is placed in a drop of pure water for examination under a microscope. ________ 6. Cell is immersed in solution of sucrose and glucose whose individual concentrations are less than concentration of solutes in cytoplasm, but whose combined concentration is greater than concentration of solutes in cytoplasm. ________ 7. Solute concentration of a cell is greater than the solute concentration of the surrounding fluid. ________ 8. Cell is exposed to a hypotonic solution. ________ 9. Concentration of solutes in a cell's cytoplasm equals the solute concentration of extracellular fluid. ________ 10. Cytoplasm is more dilute than the surrounding solution. Exercise 4 (Modules 5.1-5.9) Try to picture membranes and their functions close-up by completing the following story: Your first mission as a Bionaut requires you to enter a blood vessel and observe the structure and functions of cell membranes. You step into the water-filled chamber of the Microtron, which quickly shrinks you to a size much smaller than a red blood cell. You tumble through the tunnel-like needle and into a blood vessel in the arm of a volunteer. Huge, rubbery red blood cells slowly glide past. Floating in the clear, yellowish blood plasma, you switch on your headlamp and examine the epithelial cells of the vessel wall. Their plasma membranes seem made of millions of small balloons. These are the hydrophilic "heads" of the 1 ______________ molecules that make up most of the membrane surface. Through the transparent surface, you can see their flexible "tails" projecting inward toward the interior of the membrane and beyond them an inner layer of 2 ______________ molecules with their tails pointing toward you. Here and there are globular 3 ______________ molecules embedded in the membrane; some rest lightly on the surface, but most project all the way into the interior of the cell. The membrane is indeed a 4 ______________ mosaic; the proteins are embedded like the pieces of a picture, but you can see that they are free to move around. You push on one of the proteins, and it bobs like an iceberg. Some of the proteins have chains of sugar molecules attached to them, forming 5 ______________. These are the molecules that act as cell 6 ______________ tags. You notice that one of the proteins has a dimple in its surface. Just then a small, round molecule floating in the plasma nestles in the dimple. The molecule is a hormone, a chemical signal, and the dimpled protein is the 7_____________ that enables the cell to respond to it. The signal is relayed thorough another protein projecting into the inside of the cell, an example of signal 8______________. In your light beam, you can see the sparkle and shimmer of many molecules, large and small, in the blood and passing through the cell membrane. Oxygen is moving from the plasma, where it is more concentrated, to the cell interior, where it is less concentrated. This movement is 9 ______________; when it occurs through a biological membrane, it is called 10 ______________ transport. Similarly, carbon dioxide is flowing out of the cell, down its 11 ______________ gradient, from the cell interior, where it is 12___________ concentrated, to the blood, where it is 13 ______________ concentrated. You note that water molecules are passing through the membrane equally in both directions, many of them through protein channels called 14 ______________. The total concentration of solutes in the cell and in the blood must be equal; the solutions must be 15 ______________. You signal the control team to inject a small amount of concentrated salt solution into the blood, making the blood slightly 16______________ relative to the cell contents. This causes water to flow 17 ______________ the cell, until the two solutions are again in equilibrium. This diffusion of water through a 18 ______________ permeable membrane is called 19 ______________. Some sugar molecules floating in the blood are simply too large and polar to pass easily through the plasma membrane. The sugar molecules simply bounce off, unless they happen to pass through pores in special 20 ______________ proteins. This is a type of passive transport, because the molecules move down a concentration gradient without the expenditure of 21 ______________. Because transport proteins help out, it is called 22 ______________ diffusion. Your chemscanner detects a high concentration of potassium ions inside the cell. Transport proteins here and there in the membrane are able to move potassium into the cell against the concentration gradient. This must be 23 ______________ transport; the cell expends 24 ______________to provide energy to "pump" the potassium into the cell. Suddenly there is a tug at your foot. You look down to see your swim fins engulfed by a rippling membrane. A white blood cell the size of a house quickly pins you against the vessel wall! The phospholipids of its membrane are pressed against your face mask. The cell is engulfing you, protecting the body from a foreign invader! Taking in a substance in this way is called 25 ______________ more specifically 26 ______________ if the substance is a solid particle. Not fun if you are the particle! Suddenly the pressure diminishes, and you are inside the white blood cell, floating free in a membrane-enclosed bag, or 27 ______________. Another sac is approaching; it is a 28 ______________, full of digestive enzymes. You manage to get your legs outside of the vacuole and move it back toward the inner surface of the cell membrane. As the vacuole fuses with the plasma membrane, you tear your feet free and swim away from the voracious cell, realizing that 29 ______________ expelled you almost as fast as endocytosis trapped you! You swim to the exit point, and the control team removes you by syringe. You are soon back in the lab, restored to normal size, and telling your support team about your close call. Exercise 5 (Modules 5.10-5.13) After reading Modules 5.10-5.13, review energy, chemical reactions, and the function of enzymes by filling in the blanks in the following story. If you were to stop eating, you would probably starve to death in weeks or months. If you were unable to breathe, you would die in minutes. Organisms need the energy that is released when food and oxygen combine. This energy is used not only to move the body but also to keep it from falling apart. Energy is the ability to cause change or perform 1 ______________. The sun is the source of the energy that sustains living things. Sunlight is pure 2______________ energy, energy of movement. In the process of photosynthesis, plants are able to use the energy of sunlight to produce food molecules. This process obeys the laws of 3 ______________, the principles that govern energy transformations. Plants do not make the energy in food. According to the 4 ______________ law of thermodynamics, energy can be 5 ______________ and transferred, but it cannot be created or destroyed. In photosynthesis, no energy is created. Rather, the plant carries out a series of steps that transform the energy of sunlight into chemical energy, a form of 6 ______________ energy, stored in the chemical bonds of molecules of glucose. No energy change is 100% efficient, and the changes that occur in photosynthesis are no exception to this rule. Some of the energy of sunlight is not stored in glucose, but rather is converted to 7 ______________, which is random molecular motion. This energy is "lost" as far as the plant is concerned, and this random motion contributes to the disorder of the plant's surroundings. The 8 ______________ says that energy changes are always accompanied by an increase in 9 ______________ a measure of disorder. One of the reasons living things need a constant supply of energy is to counter this natural tendency toward disorder. The products of photosynthesis contain more potential energy than the 10 ______________. This means that, overall, photosynthesis is an 11 ______________ reaction. Such a reaction consumes energy, which in photosynthesis is supplied by the sun. Photosynthesis produces food molecules, such as glucose, which store energy. An animal might obtain this food by eating a plant or an animal that has eaten a plant. The food molecules enter the animal's cells, where their potential energy is released in the process of cellular respiration. The products of this chemical reaction (actually a series of reactions) contain less potential energy than the reactants. Therefore, cellular respiration is an 12 ______________ process; it 13 ​______________ energy. In fact, this is the same overall change that occurs when glucose in a piece of wood or paper burns in air. When paper burns, the energy escapes as the heat and light of the flames. In a cell, the reaction occurs in a more controlled way, and some of the energy is captured for use by the cell. Energy released by the exergonic "burning" of glucose in cellular respiration is used to make a substance called 14 ______________. A molecule of 15 ______________ and a 16 ______________ group are joined to form each molecule of ATP. This is an endergonic reaction, because it takes energy to assemble ATP. The covalent bond connecting the phosphate group to the rest of the ATP molecule is unstable and easily broken. This arrangement of atoms stores 17 ______________ energy. The 18 ______________ of ATP is an exergonic reaction. When ATP undergoes hydrolysis, a 19 ______________ removed, ATP becomes 20 ______________, and energy is released. Thus, ATP is a kind of energy "currency" that can be used to perform cellular 21 ______________. There are three kinds of cellular work: 22 ______________, 23 ______________, 24 ______________. Most cellular activities depend on ATP energizing other molecules by transferring its phosphate group to them —a process called 25 ______________. This happens in mechanical work, when ATP causes molecules in muscle cells to move. It should be noted that energy is not destroyed when ATP is used to do work. When an ATP molecule is hydrolyzed to make muscles move, some of its energy moves the body, and some ends up as random molecular motion, or 26 ______________. Similarly, ATP is used to move substances through 27 ______________; this is called transport work. A less obvious but important function of ATP is supplying the energy for fighting the natural tendency for a system to become disordered. A cell constantly needs to manufacture molecules to replace ones that are used up or damaged. This is chemical work. Building a large molecule from smaller parts is an 28__________ reaction. Energy released by the exergonic hydrolysis of ATP is used to drive essential endergonic reactions. The linking of exergonic and endergonic processes is called energy 29______________, and ATP is the critical connection between the processes that release energy and those that consume it. Molecules can break down; that is why ATP energy is needed to repair them. What prevents a molecule of glucose, or even ATP itself, from breaking down until its energy is needed? Fortunately for living things, it takes some additional energy, called energy of 30 ______________, to get a chemical reaction started. This creates an energy 31 ______________ that prevents molecules from breaking down without a little "push." Energy barriers exist for both exergonic and endergonic reactions. Most of the time, most molecules in a cell lack the extra energy needed to clear the barrier, so chemical reactions occur slowly, if at all. So what enables the vital reactions of metabolism to occur when and where they are needed, at a rate sufficient to sustain life? This is where enzymes come in. An enzyme is a special 32 ______________ molecule that acts as a biological 33 ______________. It 34 ______________ the rate of a chemical reaction without being 35 ______________ by it. An enzyme does not add activation 36 ______________; rather, the enzyme holds the reactants in such a way as to 37 ______________ the energy barrier that prevents them from reacting. Even though reactants would not normally possess the activation energy needed to start the reaction, the enzyme creates conditions that make the reaction possible. Enzymes enable the cell to carry out vital chemical changes when and where they are needed, enabling it to control the many chemical reactions that make up cellular 38 ______________. Exercise 6 (Modules 5.10-5.13) Briefly summarize the differences between the words or phrases in each of the following sets. 1. Kinetic energy and potential energy 2. Exergonic reactions and endergonic reactions 3. Reactants and products 4. ATP and ADP 5. A reaction without an enzyme and a reaction with an enzyme 6. Photosynthesis and cellular respiration 7. First and second laws of thermodynamics 8. Mechanical, transport, and chemical work Exercise 7 (Modules 5.14-5.16) Review enzyme action by completing the activities that follow. 1. Complete the diagram that follows so that it shows the cycle of enzyme activity. Imagine that the reaction carried out by this enzyme is splitting a substrate molecule into two parts. Color the diagram as suggested and label the items in boldface type. Color the enzyme purple. Sketch the substrate as a dark blue shape. Sketch the products, and color them light blue. Also label the active site. 2. Make a sketch showing how heat or change in pH might change the enzyme and alter its ability to catalyze its chemical reaction. Color and label the enzyme, its active site, and its substrate, as in question 1. 3. On the left side of the space that follows, make a sketch showing how a competitive inhibitor might interfere with activity of the enzyme. Label the competitive inhibitor, and color it red. On the right side, make a sketch showing how a noncompetitive inhibitor might interfere with activity of the enzyme. Label the noncompetitive inhibitor, and color it yellow. Test Your Knowledge - Multiple Choice 4. In osmosis, water always moves toward the ___ solution, that is, toward the solution with the 1. The movement of molecules from an area of ___solute concentration. higher concentration to an area of lower a. isotonic... greater concentration is called b. hypertonic. greater a. diffusion. c. hypertonic... lesser b. endocytosis. d. hypotonic... greater c. catalysis. e. hypotonic.. Lesser d. active transport. e. Osmosis. 5. Which of the following enables a cell to pick up and concentrate a specific kind of molecule? 2. Which of the following is not true of an enzyme? a. passive transport An enzyme b. diffusion a. is usually a protein. c. osmosis b. acts as a biological catalyst. d. receptor-mediated endocytosis c. supplies energy to start a chemical e. Pinocytosis reaction. d. is specific. 6. A cell uses energy released by ___ reactions to e. lowers the energy barrier for a chemical drive the ____reactions that make ATP. Then it reaction. uses the energy released by the hydrolysis of ATP, an ___ reaction, to do various kinds of work in the 3. The most abundant molecules in cell membranes cell. are a. exergonic.. exergonic.. endergonic a. cholesterol. b. endergonic.. exergonic.. endergonic b. phospholipids. c. exergonic.. endergonic.. exergonic c. glycolipids. d. endergonic... endergonic... exergonic d. proteins. e. exergonic.. endergonic... endergonic e. Enzymes. 7. Activation energy Apply the Concepts – Multiple Choice a. is released when a large molecule breaks up. b. gets a reaction going. 1. If a cell is like a factory, then enzymes are like c. is released by an exergonic reaction. a. the plans for the factory. d. is stored in an endergonic reaction. b. the machines in the factory. e. is supplied by an enzyme. c. the power plant for the factory. d. the raw materials used by the factory. 8. The laws of thermodynamics state that whenever e. the walls of the factory. energy changes occur, ____ always increases. a. disorder 2. A molecule that has the same shape as the b. order substrate of an enzyme would tend to c. kinetic energy a. speed metabolism by guiding the enzyme d. potential energy to its substrate. e. activation energy b. speed metabolism by acting as a cofactor for the enzyme. 9. Living things transform kinetic energy into c. speed metabolism because it would also potential chemical energy in the _____ when be a catalyst. is made. d. save the cell energy by substituting for a. mitochondrion... ATP the substrate. b. chloroplast... ADP e. slow metabolism by blocking the c. chloroplast…an enzyme enzyme's active site. d. mitochondrion... glucose e. chloroplast... glucose 3. A plant cell is placed in a solution whose solute concentration is twice as great as the concentration 10. Why does heating interfere with the activity of of the cell cytoplasm. The cell membrane is an enzyme? selectively permeable, allowing water but not the a. It kills the enzyme. solutes to pass through. What will happen to the b. It changes the enzyme's shape. cell? c. It increases the energy of substrate a. No change will occur because it is a plant molecules. cell. d. It causes the enzyme to break up. b. The cell will shrivel because of osmosis. e. It kills the cell, so enzymes can't work. c. The cell will swell because of osmosis. d. The cell will shrivel because of active 11. An enzyme is specific. This means transport of water. a. it has a certain amino acid sequence. e. The cell will swell because of active b. it is found only in a certain place. transport of water. c. it functions only under certain environmental conditions. 4. A white blood cell is capable of producing and d. it speeds up a particular chemical releasing thousands of antibody molecules every reaction. second. Antibodies are large, complex protein e. it occurs in only one type of cell. molecules. How would you expect them to leave 12. Diffusion of water across a selectively the cell? permeable membrane is called a. active transport a. active transport. b. exocytosis b. osmosis. c. receptor-mediated endocytosis c. exocytosis. d. passive transport d. passive transport. e. Pinocytosis e. facilitated diffusion. 5. Which of the following would be least likely to 10. In which of the following do both examples diffuse through a cell membrane without the help of a. positions of electrons in an atom — a ball a transport protein? rolling down a hill a. a large hydrophilic molecule b. heat— arrangement of atoms in a molecule b. a large hydrophobic molecule c. a rock resting on the edge of a cliff —heat c. a small hydrophilic molecule d. a ball rolling down a hill— heat d. a small hydrophobic molecule e. light arrangement of atoms in a molecule e. Any of the above would easily diffuse through the membrane. 11. Which of the following is a difference between active transport (AT) and facilitated 6. Red blood cells shrivel when placed in a 10% a. AT involves transport proteins,& FD does not. sucrose solution. When first placed in the solution, b. FD can move solutes against a concentration the solute concentration of the cells is ___ the gradient, and AT cannot. concentration of the sucrose solution. After the cells c. FD requires energy from ATP, & AT does not. shrivel, their solute concentration is ___ the d. FD involves transport proteins,& AT does not. concentration of the sucrose solution. e. AT requires energy from ATP, & FD does not. a. less than... greater than b. greater than... less than 12. An enzyme and a membrane receptor molecule c. equal to... equal to are similar in that they d. less than... equal to a. are always attached to membranes. e. greater than... equal to b. act as catalysts. c. require ATP to function. 7. A nursing infant is able to obtain disease-fighting d. supply energy for the cell. antibodies, which are large protein molecules, from e. bind to molecules of a particular shape. its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via 13. Zoologists discovered that the blood cells of a a. osmosis. certain African lungfish were much slower to swell b. passive transport. or shrink with water when faced with changes in c. exocytosis. blood solute concentration, a useful adaptation to d. active transport. drought and dehydration. The researchers e. Endocytosis. suspected that this might have something to do with the number of____ in the blood cells 8. Some enzymes involved in the hydrolysis of ATP a. phospholipids. cannot function without the help of sodium ions. b. aquaporins Sodium in this case functions as c. ATPs a. a substrate. d. competitive inhibitors b. a cofactor. e. Enzymes c. an active site. 14. The name of which of the following tells you d. a noncompetitive inhibitor. that it is an enzyme? e. a vitamin. a. folate d. ribulose b. hemoglobin 9. The relationship between an enzyme's active site c. kinase e. androsterone and its substrate is most like which of the following? 15. The first enzyme in a metabolic pathway that a. a battery and a flashlight makes ATP is blocked by ATP itself. This would b. a car and a driver appear to be an example of c. a key and a lock a. induced fit. d. feedback inhibition. d. a glove and a hand b. energy coupling. e. active transport e. a hammer and a nail c. receptor-mediated endocyt