Review Questions Exam 2
1. What are the two main cell architectures? Which contains a “true” nucleus and many membrane-bound organelles? Eukaryotic and Prokaryotic ; Eukaryotic
2. Where is DNA found in prokaryotes? Nucleoid
3. List the functions of the following eukaryotic organelles:
a. smooth endoplasmic reticulum: lipid synthesis detoxification of poisonous molecules
b. rough endoplasmic reticulum: Production of proteins that will be shipped to a specific destination, helps protein bind to tertiary shape
c. lysosomes:contains catalase
d. golgi apparatus:processes protein produces from rough ER
e. peroxisomes: site of REDOX reaction, the byproduct: hydrogen peroxide and contains enzymes to break down
f. mitochondria: manufactures ATP, contains DNA/ mitochondrial DNA
g. nucleus & nucleolus: DNA in chromosomes and DNA packaging ; sit of DNA ribosomal synthesis and assembly
4. What must proteins have in their primary structure to enter the nucleus? an NLS (Nuclear Localization Signal)
5. What is the overall purpose of the endomembrane system? sorting and movement of proteins to correct organelles
6. What must a newly made protein have in order to get into the inside (lumen) of the rough endoplasmic reticulum? A special tag or a "signal sequence"
7. What is it called when a protein receives a sugar tag? Glycosylated
8. How do proteins move between the rough endoplasmic reticulum and the golgi apparatus? by transport vehicles If you want to learn more check out What refers to the purity of light such as when something is lighter or darker?
9. What do proteins receive when they move through the stacks (cisternae) of the golgi apparatus that helps them get sorted into the correct transport vesicles? sugar tags
10. What is the definition of enthalpy? total energy in a molecule
11. What is the definition of entropy? The amount of disorder (the more disorder the more entropy)
12. What is kinetic energy? Energy of movement/motion
13. What is potential energy? stored energy due to position
14. What does the 1st law of thermodynamics state? Energy cannot be created or destroyed but only transferred and transformed
15. What is the term for reactions that release heat? Absorb heat? exothermic released as heat & endothermic absorb heat Don't forget about the age old question of How would you compare cimabue to giotto?
16. What is entropy a measure of? The amount of disorder
17. What does the 2nd law of thermodynamics state? in all spontaneous reactions, entropy increases
18. What is free energy? energy available to do free work
19. The change in free energy over the course of a reaction is a function of what three properties? The change in ____ & ______ and also the _______. temperature, enthalpy, entropy
20. What is the formula for Gibb’s free energy? Define the variables. △G = △H - T△S We also discuss several other topics like A share of stock is worth $100, and 5 years later its worth $175. what is the average rate of growth over those 5 years?
21. Spontaneous reactions – do they require a constant input of energy? What is the change in free energy (gain + or loss -) ΔG? What is the change in entropy ΔS? What is the likely change in enthalpy ΔH? Is energy absorbed or released over the course of the reaction?
Be able to identify a graph. No; released in reaction (exergonic) ; △G- loss of free energy ;△S becomes higher, while △H becomes lower
22. Non spontaneous reactions - do they require a constant input of energy? What is the change in free energy (gain + or loss -) ΔG? What is the change in entropy ΔS? What is the likely change in enthalpy ΔH? Is energy absorbed or released over the course of the reaction? Be able to identify a graph. Yes, absorbed (endergonic) ; △G+ gain of free energy ; If you want to learn more check out What is probability according to frequentists?
23. What is a reaction’s activation energy (Ea)? Do even spontaneous reactions have activation energy? We also discuss several other topics like How does acid rain occur?
24. What is the transition state? High energy intermediate state of reactants that must be achieved for a reaction to proceed
25. What is a catalyst? How do enzymes act as catalysts? Include Ea in your answer. a catalyst is an enzyme that speeds up a reaction ; binds substrates
26. Where does a substrate bind to an enzyme? What occurs to enzyme shape with this binding? binds at active site and undergoes induced fit; straining bonds of reactants
27. What are cofactors? inorganic ions (not carbon based)
28. What are coenzymes? small organic molecules (carbon based) If you want to learn more check out What is fauvism?
29. How do competitive inhibitors regulate enzyme reactions? Where do they bind to an enzyme? It will decrease reaction rate, binds at substrate.
30. What are allosteric regulators? What are the two types? Where do they bind to an enzyme? molecule binds to a different site on the enzyme ; regulation and inhibition ; bind to a different place on molecule thats not active site
31. Describe negative feedback inhibition. When a final product of a multistep enzyme pathway inhibits an earlier enzyme in the pathway to regulate the pathway.
32. Do all enzymes work under the same optimal environmental conditions? No.
33. What is meant by “energetic coupling”? Between two different types of reaction ( exergonic and endergonic reaction)
34. Why does ATP have high potential energy? What does the cell break off during hydrolysis of ATP? What is released in this reaction? - ATPs clustered negative charges give it High P.E. ; Phosphates ; Energy is released
35. What happens to the energy level of the a reactant that receives a phosphate group from ATP and becomes an “activated substrate”? How is this important to the reaction? Clustered negative chargers raise the potential energy of linked phosphate group
36. What is the process by which the energy stored in sugars (and other molecules such as fats) is converted to ATP? glycolysis
37. In a reduction-oxidation (REDOX), what is being transferred between the reactants? Electrons
38. What is meant when a molecule is oxidized? Reduced? losing electrons ; gaining electrons
39. Does an oxidized or reduced molecule gain potential energy? reduced 40. When a molecule is reduced, what kind of bond does it often gain?H bond 41. Cellular respiration in the presence of oxygen is called? Aerobic respiration
42. Contrast catabolic versus anabolic reactions. Which type of reaction is hydrolysis? Dehydration/condensation? Catabolic: break down molecules - Anabolic: synthesize or combine molecules ; Hydrolysis: dehydration
43. What are the four main “steps/groups of reactions” in aerobic cellular respiration? Glycolysis,Pyruvate processing ,Citric acid cycle, Electron transport and oxidative phosphorylation.
44. What is the overall equation of aerobic cellular respiration? What is being reduced? Oxidized? Glucose (C6H12O6) + 6 Oxygen (O2) ---> 6 Carbon Dioxide (CO2) + 6 water (H2O)
45. What is the purpose of NAD+ and FAD+? electron carriers
46. In the first steps of glycolysis, what is invested to make glucose a very high energy molecule? 2 ATP
47. In the payoff phase of glycolysis, how many ATP are produced? What is the net gain of ATP? 4 produced so net gain of 2
48. What is the mechanism of ATP production in the steps of glycolysis? Phosphate comes out of ATP and gets used for energy so glucose can become unstable and break
49. How many NAD+ are reduced in glycolysis? 2
50. In addition to ATP & reduced electron carriers (NADH), what are the other products of glycolysis? 2 pyruvate
51. Where in the cell do the steps of glycolysis occur? After these reactions are complete, where is most of the energy that was in glucose? Cytoplasm, most energy in pyruvate
52. How are the steps of glycolysis regulated via negative feedback inhibition? High levels of ATP inhibit enzyme
53. Pyruvate Processing: Where does it occur? What waste product is produced? How many electron carriers are reduced? Is ATP produced? What are the products of this reaction? Mitochondria matrix ; CO2 and NADH ; 2NADH are reduced ; 2 ATP produced per glucose (substrate-level phosphorylation) ; 2 Acetyl CoA
54. Where does the citric acid cycle occur in the cell? Mitochondrial matrix
55. What enters into the cycle? How many cycles per glucose? What are the products of the citric acid cycle per glucose? Acetyl CoA enters ; 8 cycles per glucose ; 6NADH and 2 FADH2
56. Study the products of the citric acid cycle, what is the main “goal” of this series of reactions? How is this series of reactions regulated? Main goal is to oxidize glucose completely ; regulated by ATP and NADH with neg feedback inhibition
57. The energy that was once in glucose is now being carried by what molecules? NADH and FADH2
58. The electron carriers from glycolysis, pyruvate processing and the citric acid cycle bring their electron carries to the _____________ located in the ______________. electron transport chain ; inner mitochondrial membrane
59. What is released as electrons move down the electron transport chain toward the final protein complex that holds oxygen? Energy
60. How are electrons shuttled between protein complexes in the lipid bilayer? By coenzyme Q and Cytochrome C
61. What forms as electrons are given to oxygen? H+
62. What is activated as electrons move down the electron transport chain toward oxygen to create a proton gradient? What kind of transport is this? Protein pumps , active transport
63. The build-up of protons in the intermembrane space (a high energy situation) is called the…. proton motive force
64. How can protons (H+) diffuse back across the inner mitochondrial membrane. What is this diffusion called? ATP synthase, by chemiosmosis
65. What is oxidative phosphorylation? when proteins cause the rotor and shaft to spin, catalyzing the phosphorylation of ADP and ATP
66. Cellular respiration in the absence of oxygen is called….. fermentation 67. In lactic acid fermentation, what is the final electron carrier? pyruvate 68. What is produced when yeast undergo fermentation? 2 ethanol
69. Compare the total yields of ATP between aerobic cellular respiration and fermentation. Aerobic Respiration is 29 and fermentation is 2