BIO 311C

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BIO 311C
2010-11-01 06:34:24

Exam 2
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  1. Major functions of the cytoskeleton
    Mechanical support, dynamic structure, and motility
  2. Microtubules provide cell with
    Support (shape/resists compression), Movement within the cell of chromosomes and organelles, movement of the entire cell
  3. What makes up microtubules?
  4. What scientific theme do microtubules use?
    Emergent properties
  5. Centrioles...
    organize microtubule assembly
  6. Centrosome (in microtubules)
    two centrioles, organizing center for spindle
  7. Basal body (in microtubules)
    one centriole, forms base of flagella or cilia
  8. Common microtubule structures
    • Cilia (windpipe, fallopian tubes, protists)
    • Flagella (sperm, protists)
  9. Microtubules are arranged in what kind of structure?
    9+2 structure (9 groups of 2 units on outside of wheel)
  10. Dynein arms
    "walk" across the microtubule doublets to create a bending movement of the flagella or cilia
  11. Which way to dynein motors move vesicles in the cell?
    Towards the nucleus
  12. Which way to kinesin motors move vesicles in the cell?
    Away from the nucleus
  13. What would you see in a cross section of a flagellum?
    a circle of 9 bundles and 2 microtubules
  14. Microtubules diameter and subunit
    25 nm, tubulin
  15. Microfilaments diameter and protein subunit
    7 nm, actin
  16. Microfilaments provide cell with...
    support (resist pulling), changes cell shape, contractile forces (muscle, cell division furrow, cell motility [pseudopodia])
  17. Microfilaments use what kind of motors to contract the muscle?
  18. Parts of the microfilament involved in the amoeboid movement (changing a cell's shape)
    • Cortex (outer cytoplasm): gel with actin network
    • Inner cytoplasm: sol with actin subunits
    • Extending pseudopodium
  19. What motor protein is used to move vesicles from ER to the Golgi?
  20. Intermediate Filaments diameter and protein subunit
    8-12 nm; keratin, lamin, and others
  21. Intermediate Filaments provide cell with
    support (cell shape), anchorage of nucleus, nuclear lamina
  22. Keratins look like
    Twizzlers pull and peel
  23. What are the three types of filaments?
    Microtubules (made of tubulin subunits), Microfilaments (made of actin subunits), and Intermediate Filaments (made of keratin or lamin)
  24. Which motor protein is abundant in muscle cells?
  25. Keratins are important for making structure of...
    hair cells, skin cells, nail beds (all dead)
  26. Why are membranes important? (5)
    • Selective permeability
    • Separating cell from non living surroundings
    • Creates unique environment within cell for specialized reactions
    • Asymmetric protein distribution
    • Cell communication, cell signaling
  27. Cells enduring a very hot environment would have phospholipids with...
    saturated fatty acid chains
  28. Components of the membrane (3)
    • Phospholipids
    • Membrane proteins (integral and peripheral)
    • Membrane carbohydrates (glycoproteins, glycolipids)
  29. Integral membrane proteins are located
    embedded in the membrane spanning the entire phospholipid bilayer; they are amphipathic
  30. Peripheral membrane proteins are located
    on the surface of the membrane and don't span the bilayer, only interacting with the phospholipid head
  31. Peripheral proteins lack
    a hydrophobic region
  32. A protein that served as a "channel" through the membrane would likely be...
    Integral membrane protein and amphipathic
  33. Membrane carbohydrates
    • "Flags" of carbohydrates on lipid or protein
    • Involved in cell-cell recognition, receptors
    • Located on external side of cell membrane
  34. Glycoproteins
    • Carbohydrate attached to protein
    • Protein receptors
  35. Glycolipids
    • Attached to lipid
    • Cell recognition (ex: ABO blood group)
  36. Six major functions of membrane proteins
    • Transport
    • Enzymatic activity
    • Signal transduction
    • Cell-cell recognition
    • Intercellular joining
    • Attachment to cytoskeleton or ECM
  37. The endomembrane system
    makes glycoproteins and glycolipids, and places them on outer portion of plasma membrane
  38. Glycoproteins are
    carbohydrates attached to proteins on the outside of the cell membrane
  39. Membranes are
    Phospholipid bilayers
  40. Sidedness of membrane is determined by
    endomembrane system
  41. Solute characteristics determine how the solute is transported: Nonpolar substances move
    freely across the membrane
  42. Solute characteristics determine how the solute is transported: Nonpolar substances
    are hindered by the bilayer
  43. Transport proteins
    facilitate movement of polar substances, and are very specific for a particular solute
  44. Two kinds of transport proteins:
    Channel proteins (passive transport) and carrier proteins (passive and active transport)
  45. Examples of passive transport of solute across membrane
    Diffusion and facilitated diffusion
  46. Diffusion is
    the tendency for molecules to spread out evenly into an available space
  47. In diffusion, each molecules moves
    randomly, but population of molecules can be directional
  48. Diffusion of solute moves in direction of
    from high concentration to low concentration
  49. Osmosis
    diffusion of water across a selectively permeable membrane
  50. When an animal cell is hypotonic in a solution...
    there are more solutes in the cell than in the surrounding solution, causing the cell to fill with water and explode
  51. When an animal cell is hypertonic in a solution...
    there is a lower concentration of solutes in the cell than the surrounding solute causing the water to move out of the cell and cause it to shrivel
  52. When an animal cell is isotonic in a solution...
    The concentration of solutes is the same inside and outside the cell
  53. When a plant cell is hypotonic in a solution...
    there are more solutes in the cell than in the surrounding solution, which makes the cell turgid-the normal state for a plant cell
  54. When a plant cell is hypertonic in a solution...
    there is a lower concentration of solutes in the cell than the surrounding solute causing the water to move out of the cell and cause it to plasmolyze
  55. When a plant cell is isotonic in a solution...
    The concentration of solutes is the same inside and outside the cell with not much net movement of water causing the cell to become flaccid or wilted
  56. Facilitated diffusion requires...
    transport proteins
  57. Channel proteins
    movement of polar or charged molecules down their concentration gradient into a cell
  58. Carrier proteins
    undergo change in shape the transports the polar/charged molecule across the membrane
  59. Active transport
    uses energy to move solutes
  60. Energy is needed in active transport because
    the solutes move against the concentration gradient
  61. Active transport uses
    carrier proteins (NOT channel proteins)
  62. An example of active transport
    Na+-K+ pump
  63. How would a steroid hormone move across the membrane into the cell?
    By simple diffusion through the membrane
  64. If you stay in a pool too long, your fingers turn wrinkly. Why?
    Skin cells become full of water because the water is hypotonic
  65. Three kinds of animal cell junctions
    tight junctions, desmosomes, and gap junctions
  66. Tight junctions
    make a seal to prevent fluids from getting in between cells (like tile grout)
  67. Desmosomes
    fasten cells together in strong sheets

    intermediate filaments anchor desmosomes in cytoplasm like nails and wooden planks
  68. Gap junctions
    communication between two cells

    allows cells to exchange small molecules
  69. What type of animal cell junction is analogous to the seal between bathroom tiles?
    Tight junctions
  70. Plant cell junction
  71. Yeast mating
    communication between two single cells
  72. Yeast mating types
    alpha and A
  73. Local communication
    signaling by direct contact
  74. Examples of local communication
    Gap junctions, cell-to-cell communication, paracrine, and synaptic
  75. Paracrine signaling
    only cells nearby will receive the signaling molecules (exocytosis)
  76. Synaptic signaling
    between two nerve cells
  77. What type of proteins are used for cell-cell recognition?
  78. Example of local and long distance signaling
    neuron communication
  79. Neuron communication
    neurons communicate with other cells (other neurons, muscle cells) at synapses

    Pre-synaptic cell releases chemical signal ("neurotransmitter") that is taken up by the post-synaptic cell, and elicits a response
  80. Synaptic signaling summary
    • 1. Two neuron cells separated by a synapse
    • 2. Pre-synaptic neuron releases neurotransmitters into gap
    • 3. Post-synaptic neuron receptors bind neurotransmitter, opens Na+/K+ channel

    Signal can be transduced along neuron (via depolarization of the membrane) and continued across many cells
  81. Hormonal long distance signaling steps
    endocrine cell-->blood vessel-->hormone travels in bloodstream to target cells-->target cell
  82. Long distance signaling in plants (4 steps)
    • 1. Caterpillar eating plant (wounded plant and chemical in saliva)
    • 2. Signal transduction pathway through leaf
    • 3. Synthesis and release of airborne chemicals
    • 4. Recruitment of parasitic wasps, which lay eggs in caterpillars
  83. Major themes of Cell Communication (3)
    -Only specific target cells recognize and respond to given chemical sign

    -Signal is received, transduced through the cells and elicits a response

    -Cell communication and signaling is often in response to some trigger
  84. Reception in signal transduction
    signal molecules bind to receptor
  85. Transduction in signal transduction
    signal is transmitted to response element
  86. Response in signal transduction
    output of signal
  87. Steps in signal transduction (3)
    Reception, transduction, and response
  88. The signal transduction pathway
    Ligand-->Receptor-->"Relay Molecules"-->Regulation of Cellular Activities
  89. In reception...
    a signal is specifically recognized by target cells.

    Only target cells will have the correct receptor to bind signal

    Like cell phones (cells) and phone numbers (signals)
  90. Receptors in signal transduction can be in
    the cell and the membrane
  91. Often, a ligand binding a receptor will
    change the shape of the receptor protein
  92. Ligand-binding receptor is an example of which theme in biology?
    Structure-function relationships
  93. Two classes of receptors
    Membrane bound receptors and intracellular receptors
  94. Membrane bound receptors
    Span the membrane
  95. Intracellular receptors
    Located in cytoplasm or nucleus
  96. What type of receptor would bind a polar ligand?
    A membrane bound receptor
  97. Two types of ligands
    Water soluble/polar ligands and hydrophobic/very small molecular ligands
  98. Intracellular receptors can sometimes be
    "transcription factors" which bind DNA and turn genes on or off
  99. Three major families of membrane receptors
    G-protein linked receptors, receptor tyrosine kinase, and ion channel receptors
  100. Membrane receptors are probably
    integral membrane proteins and amphipathic
  101. G-protein linked receptor structure
    a-helix secondary structure
  102. G-protein linked receptor involved in
    sensory perception (sight, smell), diseases
  103. After the G-protein linked receptor is activated, it
    changes its shape, therefore changing its function
  104. Receptor tyrosine kinase is both a
    receptor and an ezyme

    the receptor functions as a dimer

    phosphorylates to neighboring receptor's tyrosine amino acids
  105. Steps in activation of tyrosine kinase
    Signal molecule attaches to receptor to form a dimer

    Phosphorylates with another

    activates cellular responses
  106. Ion channel receptors are
    commonly found in the nervous system, in which the signal molecule is a neurotransmitter
  107. The Na+/K+ pump is
    an ion channel receptor function in local cell-cell communication
  108. Three types of membrane receptors
    G-protein linked receptor, receptor tyrosine kinase, ion channel receptor
  109. Transduction is
    multi-step pathway using molecules and proteins to transmit signal to response element

    • -amplifies signal
    • -but the signal itself is not transmitted
  110. Signal is transduced by
    'relay molecules'
  111. Relay molecules are often
    proteins that change shape as signal is 'carried' through the pathway and are phosphorylated
  112. Second messengers are relay molecules which are
    NOT proteins, but they broadcast the signal
  113. Common second messengers
    cAMP and Ca2+
  114. Cyclic AMP is
    an RNA molecule
  115. Steps in cAMP
    cAMP-->activates a kinase-->kinase phosphorylates to a target protein-->target protein activity changes
  116. cAMP involved in what kind of reaction?
    When scared, releases adrenaline
  117. Ca2+ acts as a second messenger is what kind of response?
    When your hand touches fire, Ca2+ is released from ER to make the microfilaments contract and pull your hand away from the fire
  118. Case studies involving the malfunctioning of signaling molecules
    Cholera and Viagra
  119. What happens in cholera?
    Vibrio cholerae in drinking water secretes a toxin which modifies the G-protein

    This G-protein is involved in salt and water excretion

    In response to the toxin, the G-protein is unable to hydrolyze GTP to GDP=ALWAYS active

    G-protein permanently signals -cAMP- intestines secrete water continuously
  120. Why does erectile dysfunction happen?
    • cGMP (like cAMP) is also a second messenger: it relaxes smooth muscle
    • In this situation, cGMP is converted to inactive GMP too quickly

    Viagra slows the conversion of cGMP to GMP so that the smooth muscle stays relaxed longer and more blood can enter the blood vessels
  121. Response is
    the output of signal which results in regulation of cellular activities and can occur in cytoplasm or nucleus
  122. Each signal or activated relay protein must be
    transient so the cell can continue to respond to new environmental cues
  123. Reversibility in signal transduction
    active state must be reset

    Ex: phosphorylation-dephosphorylation; cAMP to AMP, GTP to GDP; Ca2+ gradients re-established
  124. Metabolism is the
    sum of all chemical reactions in a cell
  125. What are the two categories of chemical reactions in a cell?
    catabolic and anabolic
  126. Catabolic reactions in a cell
    pathways break down products to release energy
  127. Anabolic reactions in a cell
    pathways synthesize products (energy can be stored in bonds between atoms)
  128. Metabolism uses what theme biology?
    Emergent properties
  129. Energy is the
    capacity to cause change
  130. Potential energy is
    energy that matter possesses because of its location or structure
  131. Chemical energy is
    energy stored in bonds between atoms (a type of potential energy)
  132. How are organisms energy transformers?
    Convert energy from chemical --> kinetic --> potential
  133. The two "rules" of Thermodynamics
    • 1. Energy can be transformed or transferred, it cannot be created or destroyed
    • 2. During every energy transfer or transformation, some energy given off as heat contributes to the disorder of the universe
  134. Entropy is a measure of
  135. To reduce entropy, we must
    use energy to build order from disorder
  136. A process that occurs without energy input is
  137. The process of transferring or transforming energy contributes to the overall
    entropy (disorder) because some energy is "lost" at each step
  138. The flow of energy in an ecosystem
    Sunlight --> Producers (plants and other photosynthetic organisms) --> Consumers (including animals); some is lost as heat --> lost as heat
  139. Chemicals cycle, while energy flows in
    one direction
  140. Global cycling in Biogeochemical cycles
    Chemical elements that can exist is gaseous phase (C, O, N, S)
  141. Local cycling in Biogeochemical cycles
    Chemical elements that exist as solids in soils (P, K, Ca)
  142. The four main reservoirs that nutrients cycle through are defined by
    • Whether they contain inorganic or organic materials
    • and
    • Whether they are directly available for use as nutrients or not
  143. In Biogeochemical cycles, organic materials available as nutrients (Reservoir A) are
    Living organisms, detritus
  144. In Biogeochemical cycles, organic materials unavailable as nutrients (Reservoir B) are
    Coal, oil, peat
  145. In Biogeochemical cycles, inorganic materials available as nutrients (Reservoir C) are
    atmosphere, soil, water
  146. In Biogeochemical cycles, inorganic materials unavailable as nutrients (Reservoir D) are
    Minerals in rocks
  147. The four important cycles
    Carbon cycle, Nitrogen cycle, Phosphorus cycle, Water cycle
  148. Where is carbon found in our bodies?
    in all organic molecules
  149. Where is nitrogen found in our bodies?
    Proteins and DNA
  150. Where is phosphorus found in our bodies?
  151. Where is water found in our bodies?
  152. Where are the major reservoirs where carbon is found?
  153. Where are the major reservoirs where nitrogen is found?
  154. Where are the major reservoirs where phosphorus is found?
    Sedimentary rock
  155. Where are the major reservoirs where water is found?
  156. What are the general features of the carbon cycle? (how is it obtained, global or local?)
  157. What are the general features of the nitrogen cycle? (how is it obtained, global or local?)
  158. What are the general features of the phosphorus cycle? (how is it obtained, global or local?)
  159. What are the general features of the water cycle? (how is it obtained, global or local?)
  160. Measuring the energy that can perform work in the cell is determined by the change in
    Free energy (deltaG)
  161. What is life?
    Life avoids decay by virtue of metabolism--building order out of disorder -Erwin Schrodinger
  162. Gibbs Free Energy (G)
    energy that can perform work in the system under uniform conditions (e.g. a cell)

    • For a given chemical reaction: ΔG = ΔH - TΔS
    • (change in free energy = change in total energy in a close system - temp in Kelvin x change in system's enthalpy)

    Decreasing entropy requires more energy
  163. Water moving from a high potential energy to low potential energy contributes to

    • High potential energy=low entropy
    • Low potential energy=high entropy
  164. Reactions at equilibrium have a ΔG=

    If cell's reactions are at equilibrium, there is no free energy, thus no energy to do work and the CELL IS DEAD (defining feature of life that an organism is never at equilibrium)
  165. ΔG<0, the process is....
    spontaneous, does not require energy
  166. ΔG>0, the process....
    requires energy to proceed
  167. Two types of reactions in metabolism
    Exergonic and Endergonic
  168. Exergonic reaction
    • "Energy outward"
    • Releases energy, occurs spontaneously
    • ΔG is NEGATIVE

    Ex: breakdown of macromolecules, hydrolysis reactions
  169. Endergonic reaction
    • "energy inward"
    • absorbs energy from surroundings, requires energy to occur
    • ΔG is POSITIVE

    (initial free energy is lower number than the final free energy)

    Ex: synthesis of macromolecules, dehydration reactions
  170. What type of reaction is breaking down glucose?
    C6H12O6 + 6O2 ---> 6CO2 + 6H2O
    Exergonic (breaking down individual monomers)

    -increasing entropy, products have less order than reactants (atoms have less order than monomers)
  171. What type of reaction is creation of glucose?
    6CO2 + 6H2O ----> C6H12O6 + 6O2
    Endergonic (plants use energy from the sun to do this)

    -requires energy to do; decreasing entropy (products have more order than reactants)
  172. Cells do three kinds of work
    • Mechanical
    • Transport
    • Chemical
  173. Cell does work by energy coupling...
    using an exergonic process to drive an endergonic one

    Ex: co-transport
  174. ATP
    provides the energy used by the cell to do work

    (a lot of potential energy and instability, straining bonds from negative charges)
  175. ATP can be used to couple...
    exergonic and endergonic reactions
  176. Kinases
    couple the energy of ATP hydrolysis to endergonic processes to "do work"
  177. When is a motor protein unstable?
    When it lifts its leg to take a step

    The motor protein is phosphorylated by ATP which changes its shape, becoming unstable
  178. Example of cell doing mechanical work with ATP
    ATP phosphorylating motor proteins
  179. Example of cell doing transport work with ATP
    ATP phosphorylating transport proteins
  180. Example of cell doing chemical work with ATP
    ATP phosphorylating key reactants (chemically unstable)
  181. Energy released from exergonic reactions is used for...
    endergonic reactions in the cell

    The energy doesn't go away, just stores it in the phosphate
  182. Enzymes are

    They speed up exergonic chemical reactions
  183. Enzyme activity is affected by
    cellular environment: pH and temperature
  184. Regulation of enzyme activity
    allosteric inhibition and activation
  185. Hydrolysis
    breaking the glycosidic bond to separate two monomers

    EXERGONIC and CATABOLIC (energy released through the breaking of the bonds)
  186. Activation Energy (EA)
    pushes reaction over the barrier, so "downhill" part of reaction can occur
  187. Exergonic reactions happen at one point, the rate at which they happen depends on
    the activation energy
  188. How do enzymes speed up chemical reactions to occur spontaneously?
    They lower the activation energy
  189. The suffix of enzymes
  190. Enzyme mechanisms for lowering EA
    • Allows substrate to assemble in proper orientation (adding energy by compression)
    • Enzyme can stretch the bonds towards 'transition state' conformation
    • Provides appropriate micro-environment for reaction to occur
    • Brief covalent interaction between side chain of amino acid and substrate
  191. Enzymes are an example of what biological theme?
    Structure function relationships
  192. What is "the handshake" when referring to enzymes?
    the "induced fit" between enzyme and substrate...changes the shape of the protein to allow the reaction to take place
  193. Enzymes have non-protein 'helpers' that promote enzyme function
    • Co-factors (inorganic metals, like Cu, Mg, Zn, Fe)
    • Co-enzymes (organic molecules, like Vitamins)
  194. Competitive inhibitors of enzymes
    Another protein or molecule that binds to the site and competes with the substrate to inhibit it from acting

    • Mimics, resembles normal substrate
    • Binds to the active site
    • Often reversible
  195. Noncompetitive inhibitors of enzymes
    inhibits the reaction, but binds in other places than the active site...changes shape of the protein and active site is affected so that the substrate cannot fit into the active site

    • Bind another part of the enzyme (not active site)
    • Enzyme changes shape as a result
    • Loses activity
  196. Allosteric regulation
    Can inhibit and activate enzyme activity

    A protein's function at one site is affected by a protein binding at another site
  197. Allosteric activator
    stabilizes the active form by binding to the REGULATORY site (not active site)
  198. Allosteric inhibitor
    stabilizes the inactive form (keeps it in the OFF position)
  199. Cooperativity
    binding of one substrate molecule to active site of one subunit locks all subunits in active conformation
  200. Respiration
    Harvesting energy by breaking chemical bonds (redox reactions and electron movement)
  201. Cellular respiration: the bottom line (formula)
    Organic compounds (sugars, fats, proteins) + O2 ----> CO2 + H2O + energy (ATP and heat)
  202. Chemical energy is a type of
    potential energy (need to access this energy by "breaking down" the molecule)
  203. Energy comes from movement of...

    • Chemical reactions transfer electrons from one reactant to another
    • In exergonic reactions, electrons will move from a higher energy level to a lower energy level
    • Releasing energy
  204. Reduction-Oxidation (redox) reactions
    Transfer electrons during chemical reactions
  205. Reduction
    gaining an electron
  206. Oxidation
    losing an electron
  207. When electrons move from less electronegative atoms to a stronger electronegative atom, the process is
    EXERGONIC (energy released)

    lose potential energy (need to add energy to get them away from the stronger atom, so that is the lower potential energy)
  208. Solar energy converted to chemical energy by....
  209. During cellular respiration, electrons
    lose potential energy and energy is released
  210. Cellular respiration
    • Enzymes facilitate this reaction
    • Enzymes can be regulated
    • Energy is released in discreet steps
  211. Why do we need food?
    • Food donates electrons in the form of H atom
    • Electrons are first harvested by NAD+ (electron acceptor)
  212. Sugar suffix
  213. Where does glycolysis happen?
  214. Where does the citric acid cycle happen?
  215. Glycolysis
    Break down glucose to pyruvate, get electrons (occurs in cytosol)
  216. Citric Acid cycle
    break down pyruvate to CO2 (occurs in mitochondria)
  217. Oxidative phosphorylation
    use energy collected in NADH to phosphorylate ADP--making ATP! (occurs in mitochondria)
  218. Glycolysis and citric acid cycle yield some ATP, but mostly yield
  219. The two phases of glycolysis
    • Phase 1: Energy investment (use 2 ATP)
    • Phase 2: Energy pay off (get 4 ATP, 2 NADH)

    Total yield= 2 ATP and 2 NADH
  220. Steps in Phase I of glycolysis (investment phase)
    • 1. Glucose is phosphorylated
    • 2. Glucose is rearranged
    • 3. Glucose is phosphorylated again
    • 4. 6C sugar is split into two 3C sugars (isomers)
    • 5. Isomerase converst one isomer into the other isomer (G3P)
  221. Steps in Phase II of glycolysis (pay off phase)
    • 1. 3C sugar is oxidized (loses e- to NAD+ to form NADH) and phosphorylated
    • 2. Phosphates used to make ATP from ADP
    • 3. Reposition remaining phosphate
    • 4. PEP is formed from repositioning of P, very unstable
    • 5. P is transferred to make ATP from ADP
    • ...if O2 go to Citric acid cycle, if NO O2 go to fermentation
  222. Net gain in glycolysis
    • Glucose --> 2 pyruvate + 2 H2O
    • 4 ATP formed - 2 ATP used --> 2 ATP
    • 2 NAD+ + 4 e- + 4 H+ --> 2 NADH + 2 H+
  223. Transition phase
    Pyruvate enters into mitochondrion and becomes Acetyl CoA
  224. Citric Acid cycle steps
    • 1. Acetyl CoA is attached to oxaloacetate
    • 2. CoA is lost and acetyl is joined to oxaloacetate to form citrate
    • 3. CO2 is removed
    • 4. ATP made from energy released from loss of CoA (substrate level phosphorylation)
    • 5. NADH, and FADH2 are formed
  225. Net gain in glycolysis and citric acid cycle
    6 CO2, 10 NADH, 2 FADH2, 4 ATP
  226. CoA and phosphate groups...
    Bind molecules and make them highly unstable
  227. Citric Acid cycle net gain
    3 CO2, 4 NADH, FADH2, ATP per glucose molecule (multiply times two)
  228. Oxidative phosphorylation steps
    • Moving electrons down ETC, to generate a Proton Motive Force
    • Using PMF to produce ATP
  229. Electron Transport Chain
    • Four large multiprotein complexes
    • Located in mitochondria inner membrane
    • Electrons move down chain loses energy at every step
    • ETC carriers undergo series of redox reactions
  230. The movement of electrons down the ETC
    • Pumps H+ into the inner membrane space
    • Creates a proton gradient across the inner membrane of the mitochondrion
  231. ATP synthase uses proton gradient to
    phosphorylate ADP
  232. Chemiosmosis
    uses potential energy of proton gradient across membrane to do work
  233. The pH and number of protons is ____ proportional
  234. In oxidative phosphorylation, electrons from ____ and ___ are used to create a ____
    NADH, FADH2, proton gradient
  235. How many ATP are generated in oxidative phosphorylation?
    34 per glucose molecule
  236. Co-enzymes in respiration
    • Vitamin B1 (thiamine): helps remove CO2 from various organic compounds
    • Vitamin B2 (riboflavin): component of FAD and FADH2
    • Vitamin B3 (niacin): component of NAD+ and NADH
  237. Efficiency of Fermentation vs Respiration
    • Glycolysis with Fermentation: 2 ATP; uses NADH as oxidizing agent; final electron acceptor=pyruvate or acetylaldehyde (to form lactic acid or alcohol)
    • Glycolysis with Respiration: 36-38 ATP; uses NADH as oxidizing agent; final electron acceptor=O2
  238. Cyanide
    • Electron transport chain inhibitor: Binds Fe group in Cytochrome a3
    • Prevents the transport of electrons
    • Disrupts respiration
    • Causes free radicals
  239. Dinitrophenol (DNP)
    • Uncoupling agent: "unhooks" ETC from chemiosmosis
    • Shuttles H+ across membrane down H+ gradient
    • Eliminates proton motive force, no ATP made
  240. Two stages of photosynthesis
    • Light reactions-harvest energy
    • Calvin cycle-fix CO2 into sugar
  241. Is photosynthesis endergonic or exergonic? anabolic or catabolic?
    Endergonic; anabolic; ΔG+
  242. Photosynthesis occurs in
  243. Phase I of photosynthesis
    • the light reactions gather energy and transfer it to electron carriers (eg NADPH) or use energy to make ATP
    • 1. electrons in chlorophyll are excited by light energy
    • 2. The splitting of H2O recovers electron lost in chlorophyll, releases O2 (source of oxygen we are now breathing)
    • 3. The electron is passed down ETC and energy is harvested by NADP+ (to form NADPH)
    • 4. A H+ gradient established by ETC and splitting of water leads to synthesis of ATP (just like in respiration)
  244. Light reaction in three acts
    • 1. Energy is captured in Photosystem II-H2O is split into oxygen and hydrogen
    • 2. Energy is transferred through Electron Transport Chain (ETC) to Photosystem I
    • 3. Photosystem I transfers electrons, reduces NADP+ to NADPH (electron carrier)
  245. Photosystem II in photosynthesis light reaction
    Harvests light energy using antenna