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cell phsys chap 14
| Question | Answer |
|---|---|
| The essential requirements for chemiosmosis are: | a membrane which has a protein pump embedded. an ATP synthase. a source of high-energy electrons (e-). |
| The proton gradient is used for... | an energy store and to drive ATP synthesis by the ATP synthase enzyme. |
| _____ ______ drives pump that pumps protons across membrane | electron transport |
| Proton gradient is harnessed by _____ _______ to make ATP | ATP synthase |
| Protons (H+) are freely available from ____ _____. The pump harnesses the energy of _______ _______ to pump protons. Creates a _______ ________ across the membrane. | water molecules; electron transport; proton gradient |
| Energy from sunlight or the oxidation of foodstuffs is first used to create an __________ _______ _______ across a membrane | electochemical proton gradient |
| The electrochemical proton gradient serves as a versatile energy store and is used to drive a variety of energy-requiring reactions in _____, _____, and _____ | mitochondria, choloroplast, and bacteria |
| The transmembrane electrochemical proton (H+) gradient is used for... | active membrane transport, ATP synthesis, and bacterial flagellar rotation |
| where is mitochondria located in cardiac muscle and a sperm tail? | near the site of high ATP utilization |
| during the development of flagellum of the sperm tail, microtubules... | wind helically around the axoneme, are thought to help localize the mitochondria in the tail then disappear, and help mitochondria fuse with one another |
| Mitochondria tend to be aligned along _____ to help form a network for motion. | microtubules |
| in the liver, an estimated 67% of total mitochondrial protein is located _________, 21% is located _______, 6% is the ________, and 6% in the _____ | in the matrix, in the inner membrane, outer membrane, intermembrane space |
| Low osmolarity readily allows water to pass and inner membrane of mitochondrial _____. High osmolarity makes it ____. | swell; shrink |
| Biochemical fractionation method makes it possible to study different proteins in each mitochondrial compartment. the method aloows the processing of large numbers of _________ | mitochondria |
| Pyruvate and fatty acids enter the mitochondrion and are broken down to _____ | acetyl CoA |
| ____ is metabolized by the citric acid cycle, which reduces ____ to NADH (and FAD to ____) | acetyl CoA; NAD; FADH |
| Pyruvate and fatty acids enter the mitochondrion and are broken down to _____ | acetyl CoA |
| ____ is metabolized by the citric acid cycle, which reduces ____ to NADH (and FAD to ____) | acetyl CoA; NAD; FADH |
| in the process of oxidative phosphorylation, high-energy electrons from NADH (and FADH2) are passed along the ___________ in the inner membrane to _______ | electron-transport chain; oxygen (O2) |
| ___________ generated by glycolysis in the cytosol also passes electrons to the respiratory chain | NADH |
| the electron transfer from cytosolic NADH must be accomplished _____ by means of one of several "shuttle" systems that transport another ______ _____ into the inner mitochondrial membrane.Compound is returned to cytosol to be reduced by _____ again. | indirectly; reduced compound; NADH |
| ____ will yield more products from oxidation of sugars and fats because it has more carbons | fats |
| Palmitoyl CoA is a ______ carbon fatty acid | 16 |
| oxidative phosphorylation converts a major part of the energy of NADH (and FADH2) oxidation into ______ _____ in ATP | phosphate-bond energy |
| the major net energy conversion catalyzed by the mitochondria | oxidative phosphorylation |
| in ____________ _________ the inner mitochondrial membrane serves as a device that changes one form of chemical bond energy to another | oxidative phosphorylation |
| the inside surface of the inner mitochondrial membrane in a plant cell has... | densely packed particles which are the protruding portions of the ATP synthases and the respiratory enzyme complex |
| what is the general mechanism of oxidative phosphorylation? | high-energy electron is passed along electron-transport chain and energy released is used to drive 3 respiratory enzyme complexes that pump H+ out of matrix. Resulting electrochemical proton gradient drives H+ back throuh ATP synthase |
| what is ATP synthase | a transmembran protein complex that uses the energy of the H+ flow to synthesize ATP from ADP and Pi in the matrix. |
| what are the three main respiratory enzyme complexes? | NADH dehydrogenase complex, cytochrome b-c1 complex, and cytochrome oxidase complex |
| during the transfer of electrons from NADH to oxygen, _____ and _____ serve as mobile carriers that ferry electrons from one complex to the next | ubiquinone and cytochrome c |
| protons are pumped across the membrane by ____ ____ ____ | respiratory enzyme complexes |
| redox potential changes along the mitochondrial electron-transport chain | true |
| NADH is the only source of electrons for the respiratory chain | false |
| what is another source of electrons for the respiratory chain? | flavin FADH2 generated by fatty acid oxidation and the citric acid cycle. It's 2 electrons are passed directly to ubiquinone, bypassing NADH dehydrogenase causing less H+ pumping than 2 electrons from NADH |
| the redox potential (E'0) increases as electrons flow down the respiratory chain to oxygen | true |
| part of the favorable free-energy change is harnessed by each enzyme complex to pump H+ across ____ | the inner mitochondrial membrane |
| cytochrome oxidase complex pumps ____ H+ per electron | one |
| NADH dehydrogenase and cytochrome b-c1 complexes each pump ___ H+ per electron | two |
| the ultimate electron receptor is ____ | oxygen (cellular/ aerobic respiration) |
| what is a hydride ion | H- a hydrogen atom and an extra electron |
| when a dydride ion is removed from NADH it is converted into... | a proton and two high-energy electrons: H- --> H+ + 2e- |
| hydride ions split... | protons and electrons |
| electron transfer can result in the transfer of entire ____ ____ | hydrogen atoms |
| where are protons readily accepted from or donated to water? | inside cells |
| electron carriers proceed to ______ intermediate | transient |
| An electron passes along an electron-transport chain embedded in a _____ ____ | lipid-bilayer membrane which can bind and release a proton at each step |
| Ubiquinone picks up ______ H+ from the aqueous environment for every ______ it accepts | one; electron |
| __________ can carry either one or two electrons as part of a hydrogen atom | Ubiquinone |
| what happens when ubiquinone is reduced? | ubiquinone donates its electrons to the next carrier in the chain, the protons are released |
| A long hydrophobic tail confines ubiquinone to the membrane and consists of _______ five-carbon _______ units, the nember depending on the organism | 6-10; isoprene |
| the corresponding electron carrier in the photosynthetic membranes of cholorplast is ______, which is almost identical in structure | plastoquinone |
| Both ubiquinone and plastoquinone are referred to as ____ | quinone (Q) |
| Quinone electron carriers picks up from NADH cytochrome complex and donates to __________ | cytochrome b-c1 complex |
| Cytochrome b-c1 is a _____ and ______ monomer composed of _____ different protein molecules in mammals | dimer; 240,000-dalton; 11 |
| what is the functional core of the enzyme cytochrome b-c1? | cytochrome b, cytochrome c1, and rieske protein containing and iron-sulfur center |
| explain the structure of the heme group attached covalently to cytochrome c | five different cytochromes in the respiratory chain. The hemes in different cytochromes have slightly different structures and are held by their respective proteins in diff ways. each of the cytochromes has a diff affinity for an electron |
| explain the molecular structure of cytochrome oxidase | protein is a dimer formed from a monomer with 13 different protein subuinits (monomer mass of 204,000 daltons). As electrons pass through this protein on the way to its bound O2 molecule, they cause the protein in to pump protons across the membrane. |
| How many protons are pumped out of the matrix for each O2 molecule that undergoes the reactions with electrons in cytochrome oxidase? | 4. 4e- + 4H+ + O2--> 2H2O |
| what does the iron atom in heme a serve as? | an electron queuing point |
| what is the bimetallic center acive site formed by? | the other heme-linked iron and closely opposed copper atom |
| Heme a feeds 4 electrons into an O2 molecule held at the ________ _______ active site | Bimetallic center |
| In the general model for H+ pumping,the protein is driven through a cycle of ___ conformations which have different energies | 3 |
| Because the overall cycle releases free energy, H+ is pumped from _________ to the __________ | Inside (from the matrix) to the outside (inter membrane space) |
| For cytochrome oxidase, the energy equites for the transition B -->C is provided by __________ _________, whereas for bacteriorhodopsin, this energy is provided by _________. Energy for other proton pumps is derived from _______ | Electron transport; light; ATP hydrolysis |
| In H+ pumping when the protein has a high affinity for H+ what happens? | The protein pick up a H+ on the inside of the membrane |
| Conformational changes leading to a lower state of energy proceed ____________ | Spontaneously |
| Transition from a high affinity conformation to a low affinity cconformation for H+ releases the H+ ( energetically unfavorable). Why does this happen? | Because it is driven by being allosterically coupled to an energetically favorable reaction occurring elsewhere on the protein |
| What happens in H+ pumping when the protein has a low affinity for H+? | H+ is released on the outside of the membrane |
| Both F1 and F0 are formed by _______ ________ | Multiple subunits |
| A _______ _______ turns with a rotor formed by a ring of 10 to 14 c subunits in the membrane | Rotating stalk |
| The ______ is formed from transmembrane a subunits, tied to other subunits that create an elongated arm which fixes the ____ to a ring of ___ and ___ subunits that form the head | Stator; stator; 3 alpha and 3 beta |
| The three dimensional structure of ____ ____, determined by dray crystallography derives it's name from it's ability to carry out the reverse of the ATP synthesis reaction (hydrolysis of ATP to ADP and Pi) when detached from the transmembrane portion | F1 ATPase |
| The total proton-motive force across the inner mitochondrial membrane consists of... | A large force due to membrane potential (delta psi or delta V) and a smaller force due to the H+?concentration gradient (delta pH). Both forces act to drive H+ into the matrix |
| Pyruvate, inorganic phosphate (Pi) and ADP are moved _____ the matrix, while ATP is ________ | Into; pumped out |
| The outer membrane is _______ permeable to compounds oyruvate (Pi), ADP and ATP | Freely |
| The mitochondria is only used for ATP production in cell metabolism | False |
| What does the human mitochondrial genome contain? | 2 rRNA genes, 22tRNA genes, and 13 protein-coding sequences |
| What are the contributions of the mitochondrion to it's genetic system | mRNAs, rRNAs, and tRNAS |
| Proteins encoded in the nucleus and imported from the cytosol have a major role in... | Creating the genetic system of the mitochondrion |
| Additional nucleus-encoded proteins regulate the expression of __________ __________ ________ at _______________ levels | Individual mitochondrial genes at posttranscriptional levels |
Created by:
jacquess17