Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Metabolic network modelling wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Biochemistry wikipedia , lookup
Photosynthesis wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Oxidative phosphorylation wikipedia , lookup
DIFFUSION, MEMBRANES, AND METABOLISM What Is a Concentration Gradient? What Determines Diffusion Rates? Membrane Crossing Mechanisms rmrl Your Liver INPUTS AND OUTPUTS OF ENERGY The Flow of Energy and Down the Energy Hills ATP~The Cell's Energy Currency INPUTS AND OUTPUTS OF SUBSTANCES The Nature of Metabolic Reactions Redox Reactions of Metabolic HOW ENZYMES MAKE SUBSTANCES REACT ENZYMES DON'T WORK IN A VACUUM Effects of and HOW THE MEMBRANE TRANSPORTERS WORK Passive Transport Active Transport WHICH WAY WILL WATER MOVE? Movement of Water Effects of Tonicity Effects of Fluid Pressure MEMBRANE TRAFFIC TO AND FROM THE CELL SURFACE Endocytosis and Exocytosis Membrane [pp.72-73] [pp.7 Ll-75] [pp.76-77] For additional practice, use the interactive vocabulary exercises linked with your BiologyNow CD-ROM. Selected Words: "alcohol" [p.n], alcoholic hepatitis [p.72], alcoholic cirrhosis [p.72], binge drinking [p.73], "entropy" [p.74], el1dergonic [p.74], "energy hill" [p.75], exergol1ic [p.75], coupling [p.75], reactants [p.76], intermediates [p.76], products [p.76], energy carriers [p.76], enzymes [p.76], cofactors [p.76], transport proteins [p.76], "redox" reactions [p.76], biosynthetic [p.77], degradative [p.77] Boldfaced [p.73] metabolism _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _~ L [p.7 l] energy ==========--_________________=========== How Cells Work 55 [p.74] first law of thermodynamics _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.74] second law of thermodynamics _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.75] ATP _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.75] phosphorylations [p.75] ATP / ADP cycle _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.76] catalysts [p.76] chemical equilibriulTt _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.76] oxidation-reduction reactions _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.T7] electron transfer chains [p.77] metabolic pathways Match each of the following terms with its definition. [All are from pp.72-73.] 1. alcoholic hepatitis 2. catalase 3. alcoholic cirrhosis 4. binge drinking 5. acetaldehyde 6. metabolism a. The cell's capacity to acquire energy and use it in controlled ways b. A breakdown product of alcohol that is toxic to cells c. A disease characterized by inflammation of the liver d. The consumption of large amounts of alcohol in short periods e. The liver enzyme that assists in the breakdown of alcohol f. The permanent scarring of the liver due to alcohol abuse If the statement is true, write a "T" in the blank. If the statement is false, correct it by crossing out the underlilted word(s) and writing the correct word(s) in the answer blank. [p.74] _____ 7. The first law of thermodynamics states that entropy is constantly increasing in the universe. _____ 8. The conversion of energy from one form to another is always 100 percent efficient. _____ 9. Energy may be converted between forms. 10. The entropy of the universe is decreasing. 56 Chapter Five In the blank preceding each item, indicate which law of thermodynamics applies [p.74] a. first law of thermodynamics b. second law of thermodyn.anLics _____ 11. Corn plants producing starch molecules _____ 12. Oak logs burning in a fireplace _____ 13. The death and decay of an organism _____ 14. The use of energy to power muscle movement Indicate whether each of the following is an example of an [pp.74-75] a. endergonic reaction b. exergonic reaction _____ 15. The release of energy from chemical bonds _____ 16. The process of photosynthesis _______. 17. The storage of energy in chemical bonds 18. The process of aerobic respiration All cells stay alive by (19) [p.75] energy inputs to energy outputs, mainly with adenosine triphosphate, or (20) (21) [p.75]. This nucleotide consists of the [p.75], the base (22) groups. ATP readily gives up a (24) sugar [p.75], and three (23) [p.75] [p.75] group to other molecules and primes them to react. These transfers are known as (25) ATP is the (26) five~carbon [p.75]. [p.75] in a cell's economy. Cells earn it by investing in (27) _ _ _ _ _ _ [p.75] reactions. They spend it in (28) energy~ energy~ [p.75] reactions that keep them. alive, When ATP gives up a phosphate, (29) inorganic (30) is called the (31) [p.75] forms. ATP can form when ADP binds to [p.75] or to a phosphate group that was split from a different molecule. This [p.75] cycle. Match each of the following terms with its definition. [All are from p.76.] _ _ _ _ 32. products _ _ _ _ 33. metabolic pathways _ _ _ 34. enzymes - _ _ _ 35. cofactors 36. chemical equilibrium _ _ _ 37. transport proteins _ 38. reactants _ 39. intermediates a. b. c. d. e. The starting substances of a chemical reaction The end products of a chemical reaction Enzyme assistants An ordered, enzyme~assisted series of reactions Exists when the forward and reverse rates of a chemical reaction are equal f. Substances that are formed during a chemical reaction g. Catalysts that speed up the rate of a chemical reaction h. Move solutes across membranes How Cells Work 57 For each of the following, choose whether the statement refers to a or b. [p.77] a. degmdative pathway b. biosynthetic pathway _ _ _ _ 40. Anabolic reactions _ _ _ _ 41. The process of aerobic respiration _ _ _ _ 42. Catabolic reactions _ _ _ _ 43. The process of photosynthesis _ _ _ _ 44. Requires an input of energy _ _ _ _ 4S. Results in a release of energy Fill in the Blanks Individual cells capture free (46) _ _ _ _ _ _ [p.76], store it, and then release it in manageable bits. They (47) [p.76] the energy they require to maintain themselves, grow, and (48) [p.77]. Cells release energy efficiently by electron transfers, or (49) _ _ _ _ __ [p.76]. In these reactions, one molecule gives up electrons, or is (SO) [p.76], and another gains them, or is (Sl) _ _ _ _ _ _ [p.76]. Corrunonly, (52) _ _ _ _ _ _ [p.76] atoms are released at the same time. Start thinking about redox reactions because they are central to photosynthesis and aerobic respiration. In the next two chapters, you'll see how (S3) _ _ _ _ _ _ [p.77] pick up electrons and H+ stripped fronl. substrates and deliver them to (54) [p.77]. Such chains are membrane-bound arrays of (S5) _ _ _ _ _ _ [p.77] and other molecules that accept and give up electrons in sequence. Electrons are at a (S6) [p.77] energy level when they enter a chain then when they leave. [pp.78-79] [pp.80-81] Terms: functional group tmnsfers [p.78], electron transfers [p.79], rearml1gements [p.79], condensation [p.79], cleavage [p.79], "binding energy" [p.79],free radicals [p.80], allosteric [p.80] Boldfaced Terms [p.78] activation energy _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.78] substrates _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ 58 Chapter Five [r.7S] active sites [r.79] transition state _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [r.79] induced-fit model _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [r.SO] coenzymes [r.SO] antioxidants _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [r.SO] feedback inhibition _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ In the diagram choose the correct term for each label. [p.78] 1. 2. lJ, 3. !:i. a. Total energy released by the reaction b. Activation energy with enzyme activity c. level of the starting substance Activation energy without enzyme level of the product 5 forward reaction _ _ :2 ~----~---~------ How Cells Work 59 Each of the terms listed or described in the following table represents a type of Complete the table by supplying each missing term or description. [pp.78-79] enzyme~mediated reaction. DescriptioJ1 Terlll A larger molecule splits into smaller ones. 6. 7. functional group transfers One or more electrons are stripped from one molecule and donated to another. 8. 9. rearrangements 10. condensation Match each of the following terms with its definition. [pp.78-79] 11. induced-fit model 12. active site 13. activation energy ILl binding energy 15. substrates 16. transition state a. b. c. d. The site where the specific reactions of an enzyme occur The reactants of a chemical reaction The nriI)imum energy required to get a reaction going The point at which the bonds in the substrate are at their breaking point e. Interactions between the substrate and the enzynce that change the shape of the enzyme f. The energy that stabilizes the transition state Four mechanisms work alone or in combination to get substrates to the transition state. First, subsh'ate molecules rarely react at (17) substrate (18) [p.79] concentrations. Binding at an active site boosts local [p.79l by as much as ten millionfold. Second, on their own, substrates collide from random directions. By contrast, weak but extensive bonds at a(n) (19) _"__"_""_ _ _ [p.79] put reactive groups close together. Third, because of its ability to form (20) [p.79l bonds so easily, water can interfere with the breaking and formation of bonds during reactions. Some (21) [p.79] are populated by (22) _ _ _ _ _ _ [p.79] amino acid residues. The (23) _______ [p.79] groups keep water away from the active site and reactions. Fourth, weak interactions between the enzyme and its (24) _ _ _ _ _ _ [p.79] may induce the enzyme to change its shape. By the (25) _________ [p.79l, a substrate is not quite complementary to an active site. The enzyme bends and optimizes the fit; in doing so, it pulls the substrate to the (26) _ _ _ _ _ _ [p.79] state. 60 Chapter Five Match each of the following definitions with the correct term. Some answers may be used more than once. [p.80] _____ 27. Assists in the neutralization of free radicals a. b. c. d. _ _ _ _ 28. When the final product of the pathway has the ability to shut down the pathway feedback inhibition allosteric coenzymes antioxidants _____ 29. Organic cofactors _ _ _ _ 30. All vitamins belong to this group _____ 31. A regulatory site on an enzyme that is used in feedback inhibition (32) [p.81] is the measure of molecular lTlOtion. As it rises, it boosts (33) _ _ _ _ __ [p.81] both by increasing the likelihood that a substrate will bump into an enzyme and by raising a (34) [p.81] molecule's internal energy. Above or below the range of temperature that an enzyme can (35) (37) [p.81], weak bonds break and enzyme (36) [p.81] can no longer bind to the (38) [p.81] changes. [p.81], and reaction rates fall sharply. In the human body, m.ost enzymes work best when the pH is between (39) and _ _ _ _ _ [p.81]. Most enzymes don't work well when the fluids in which they are dissolved are (flO) (L11) [p.81] or less salty than their range of tolerance. Too rnuch or too little [p.81] interferes with the (42) _ _ _ _ _,_ [p.81] bonds that help hold an enzyn,e in its three-dimensional shape. [pp.82-83] [pp.84-85] gradient [p.82], passive tral1sport [p.83], "facilitated" diffusion [pp.83-84], active transport [p.83], exocytosis [p.83], endocytosis [p.83], net direction of movement [p.84] Boldfaced [p.82) selective permeability _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.82] concentration gradient _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.82) diffusion _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ [p.83] electric gradient _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ How Cells Work 61