Ch 14

Describe how mitochondrian can divide like a bacterium. Relate to mitochondria. Sig?

-Mitochondria replicate via binary fission A: Suggests that mitochondria were bacteria taken up by eukaryotic cells

How do concentration changes impact redox potential? Relate to mitochondria. Sig?

-More of the the electron donor leads to more negative E so more negative redox potential -If there is excess NADH, there is stronger electron donation due to this. A: Shows how production of ATP can be enhanced

Describe how NADH donates its high energy electrons to the ETC. Relate to mitochondria. Sig?

-NADH can donate a hydride ion that gives off electrons to the electron transport chain -NAD+ is then formed via bond rearrangement A: Provides electrons that help form proton gradient, that help provide means to provide energy

Describe how mitochondria catalyze a major conversion of energy. Relate to mitochondria. Sig?

-Mitochondria permits energy stored in NADH to be used to make ATP A: Produces very important energy containing molecule

What is the respiratory chain? Relate to mitochondria. Sig?

-Another name of electron transport chain for making ATP A: Vital for making ATP, vital cellular nutrient

Describe how ATP synthase acts like a motor to convert the energy of protons flowing down their electrochemical gradient to chemical bond energy in ATP. Relate to mitochondria. Sig?

-As Hydrogen atoms move down their concentration gradient, help rotate ATP synthase motor to accomplish ATP synthesis via providing some energy in rotation A: Clever method of producing the all important ATP

Describe how the orientation of a membrane embedded electron carrier allows electron transfer to drive proton pumping. Sig?

-As electron passes along an ETC, can bind and release proton at each step, thus permitting ability to move protons into intermembrane space to build that concentration and EC gradient A: Helps fuel ATP synthesis

Describe how as electrons are transferred from activated carriers to oxygen, protons are pumped across inner mitochondrial membrane. Relate to mitochondria. Sig?

-As electrons move down the ETC, the energy they give off is used to move hydrogen atoms into the intermembrane space to build the concentration gradient A: The gradient made is ultimately used to make ATP

Describe how the cytochrome c oxidase is a finely tuned protein machine. Relate to mitochondria. Sig?

-As electrons pass through protein on the way to its bound O2 molecule, they cause the protein to pump protons across the membrane A: Provide energy to fuel ATP synthase and make ATP

Describe how acetyl CoA is produced in eukaryotic mitochondria from molecules derived from sugars and fats. Relate to mitochondria. Sig?

-Breakdown of sugars and fatty acids ultimately yield acetyl CoA in the mitochondria A: Show that the mitochondria assists in formation of intermediates as it makes ATP

Describe how oxidative phosphorylation might have evolved in stages. Relate to mitochondria. Sig?

-Cell likely first developed ATPase to pump protons out of cell -Then likely evolved ETC protein that pumps protons -Then a system would have developed that paired these systems to make ATP A: Provides explanation for origin of ATP pump process

Summarize energy generation in mitochondria. Relate to mitochondria. Sig?

-Cells obtain most of their energy by a membrane based mechanism -Chemiosmotic coupling is an ancient process, preserved in present-day cells A: Important process for our cells that likely due to evolutionary events long ago

What are brown fat cells? Relate to mitochondrial chemiosmotic coupling. Sig?

-Cells where most of the energy from oxidation of fat is dissipated as heat rather than converted into ATP A: Example of cells where uncoupling of chemiosmotic coupling occurs

Describe how the electrochemical H+ gradient across the inner mitochondrial membrane includes a large force due to membrane potential and a smaller force due to the concentration gradient. Relate to mitochondria. Sig?

-Charge differential and concentration gradient lead to movement of H+ ions across membrane with high energy exchange, helping to provide energy for ATP synthesis via ATP synthase A: Produces vital cellular energy

Describe oxidative phosphorylation. Relate to mitochondria. Sig?

-Chemiosmotic mechanism for ATP synthesis that involves both the consumption of O2 and the addition of a phosphate group to ADP to form ATP A: Mechanism of making ATP

Describe cytochrome c. What does the greek word chroma mean? Relate to mitochondria. Sig?

-Chroma: color -Cytochrome c is a small protein that accepts electrons from the cytochrome c reductase complex and transfers them to the cytochrome c oxidase complex A: Keeps electrons moving down the ETC, assuring ATP made in adequate amounts

What are cytochromes? What are they made of? Relate to mitochondrial ETC. Sig?

-Complex in ETC made of heme groups and act as electron carrier -Increase in redox potential along the ETC to assure electrons keep moving along A: Help pass electrons along so ATP will be made

What is quinone? Relate to ETC. Sig?

-Complex similar to ubiquinone that delivers electrons to next complex in line in the ETC of photosynthesis A: Shows importance of electron transport

What are the respiratory enzyme complexes? What are they in order? Relate to mitochondria. Sig?

-Complexes in mitochondria that contain multiple individual proteins to accomplish electron transport and production of ATP -Complexes: NADH dehydrogenase complex, ubiquinone, cytochrome c reductase complex (b-c1 complex), cytochrome c, cytochrome c oxidase complex A: Permit electron transport that is vital for ATP synthesis

Describe experiments where bacteriorhodopsin and bovine mitochondrial ATP synthase were introduced into liposomes to understand mitochondrial action. Relate to mitochondria. Sig?

-Discovered that hydrogen ion movement through ATP synthase is required to produce ATP A: Provided evidence that proton gradients can power ATP production

Describe how redox potential increases along the mitochondrial electron transport chain. Relate to mitochondria. Sig?

-Each complex has a higher redox potential than the one before it, so electrons tend to move along the chain A: Assure electrons moved to build proton gradient so ATP can be made in adequate amounts

Describe how high energy electrons are transferred through three respiratory enzyme complexes in the inner mitochondrial membrane. Relate to mitochondria. Sig?

-Electron carriers put electrons into the complexes of the ETC and they pass electrons along A: Vital for production of ATP

Describe how membrane based mechanisms use the energy provided by food to generate ATP. Relate to mitochondria. Sig?

-Energy from food is used in oxidative phosphorylation to cause electron transfers, that pump protons across mitochondrial membrane -Proton gradient then used to make ATP A: Produces vital energy containing molecule for the cell

Describe how ATP synthase is a reversible coupling device. Relate to mitochondria. Sig?

-Enzyme can either synthesize ATP by harnessing H+ gradient or pump protons against this gradient by hydrolyzing ATP A: Show how enzymes can catalyze forward or reverse reactions

What is cytochrome c oxidase? Relate to mitochondria. Sig?

-Final electron carrier in the respiratory chain that has the highest redox potential of all -Removes electrons from cytochrome c, oxidizing it A: Final electron carrier and permits reduction of oxygen to make ATP

Compare the ATP yields for each of the glucose oxidation steps. Relate to mitochondria. Sig?

-Glycolysis: produces equiv of 5 -Pyruviate oxidation: produces equiv of 5 -Complete acetyl CoA oxidation: produces equiv of 20 A: Produces lots of vital ATP energy

What is an electrochemical gradient. Relate to mitochondria. Sig?

-Gradient that is product of voltage across membrane and ion concentration gradient A: Vital for running hydrogen ions along and producing ATP

What is proton-motive force? Relate to mitochondria. Sig?

-Gradient that is significantly impacted by membrane potential that pulls Hydrogen ions back across the membrane -The energy is used to synthesize ATP A: Vital for producing ATP, important material for cellular action

What is the chemiosmotic hypothesis? What did it become known as? Relate to mitochondria. Sig?

-Hypothesis about the mechanism of ATP production in mitochondria that relies on proton gradient and ATP synthase -Became known as chemiosmotic coupling A: Permit cells to harness energy of electron transfers to do work via ATP energy

Describe how batteries can use the energy of electron transfer to perform work. Relate to mitochondria action. Sig?

-If batteries solely connected to wire, all chemical energy from electron transfer converted to heat energy -If connected to pump, chemical energy from electron transfer converted to potential energy stored in difference in water levels, thus less energy is lost as heat energy A: Show how mitochondria employ technique to conserve energy when they produce ATP

Describe how mitochondria often fuse to form elongated tubular networks that extend throughout cytoplasm. Relate to mitochondria. Sig?

-Illustrates how mitochondria can change their shape, location, and number to suit a cell's needs A: Shows the variety of shapes that mitochondria can exhibit

Describe how some mitochondria are located near sites of high ATP utilization. Relate to mitochondria function. Sig?

-In cardiac muscle cell, mitochondria located close to contractile apparatus where ATP hydrolysis required for contraction A: Shows how mitochondria tend to be located where they are used most

What are cristae? Relate to the mitochondria. Sig?

-Infoldings in the mitochondria's inner membrane that greatly increase SA of the membrane A: Make it so lots of ATP synthesis can occur at any given time, so we can survive

What are myoclonic epilepsy and ragged red fiber disease? Relate to mitochondria. Sig?

-Inherited disorders where people are deficient in multiple proteins required for electron transport leading to problems like muscle weakness and heart problems A: Show importance of electron transport chain and ATP formation

Describe how the iron in a heme group can serve as an electron acceptor. Relate to mitochondria. Sig?

-Iron can accept electrons to move electrons along the ETC A: Keeps moving electrons along so ATP can be ultimately made

What is ATP synthase? Relate to mitochondria. Sig?

-Large, multisubunit protein embedded in inner mitochondrial membrane that catalyzes formation of ATP A: Produces the all important ATP

How does Methanococcus represent life forms that might have existed early in Earth's history? Sig?

-Lives off of compounds and in type of environment only conducive to organisms back in the old days A: Can be used to study the origins of life

Describe the mitochondria and oxidative phosphorylation. Relate to mitochondria. Sig?

-Mitochondria can change shape, location, and number to suit cell's needs -Mitochondria contain outer membrane, inner membrane, and two internal compartments -TCA cycle generates high energy e- needed for ATP production -Electron movement coupled to proton pumping -Protons pumped across inner mitochondrial membrane by ETC proteins -Proton pumping makes steep EC proton gradient across inner mitochondrial membrane -ATP synthase uses energy stored in EC proton gradient to make ATP -Coupled transport across inner mitochondrial membrane is also driven by EC proton gradient -Rapid conversion of ADP to ATP in mitochondria maintains high ATP/ADP ratio in cells -Cell respiration is amazingly efficient A: Permits cell to make energy molecules, which are vital for functioning

Describe how mitochondria share many of the features of bacterial ancestors. Relate to mitochondria. Sig?

-Mitochondria have their own DNA-based genome and machinery to copy this DNA and make RNA and protein A: Suggest mitochondria used to be its own bacterium and was taken up by eukaryotic cells

Describe how redox potentials are measured. What does it mean if electrons flow towards H+ beaker? Relate to mitochondria. Sig?

-One beaker has substance with reduced and oxidized forms, the other beaker has the hydrogen standard -You have a wire with a voltmeter attached and you measure which direction it flows in with if ions flow towards H+, you have negative redox potential. Positive if from H2 to substance. -Can also be used to measure potential of ETC A: Can be used to understand mechanics of ETC

What are mitochondria? Relate to mitochondria. Sig?

-Organelles in eukaryotic cells that produce the bulk of the cell's ATP A: Important for permitting a number of cellular processes to occur

From outer surface to inner surface, name the layers of the mitochondria. Relate to mitochondria.

-Outer membrane -Intermembrane space -Inner membrane -Matrix

Describe the mitochondria's outer membrane and porin. Contrast to inner membrane's permeability. Relate to mitochondria. Sig?

-Outer membrane contains many molecules of transport protein called porin that forms wide aqueous channels through lipid bilayer -This makes cell impermeable to anything bigger than 5 kD -Inner membrane is impermeable to ion and small molecule passage except at transport proteins A: Helps make the anatomy of the mitochondria, which is vital for making energy for cellular processes

Describe the evolution of energy-generating systems. Relate to mitochondria. Sig?

-Oxidative phosphorylation evolved in stages -Photosynthetic bacteria made even fewer demands on their environment -The lifestyle of Methanococcus suggests that chemiosmotic coupling is an ancient process A: Shows how ATP synthesis developed over time

Describe how electron transfers can cause the movement of entire hydrogen atoms, because protons are readily accepted from or donated to water. Relate to mitochondria. Sig?

-Oxidized electron carrier molecule can pick up electron plus proton when reduced and when it is reduced, loses electron plus proton when oxidized. A: Permit hydrogen and electron movement, which are important for the ETC

What are redox pairs? Relate to mitochondrial function. Sig?

-Pair of compounds that are oxidized and reduced to form one another, like NADH and NAD+ A: The different compounds have different properties, NADH providing electrons for ETC and ATP synthesis

What is a redox potential? Relate to mitochondrial function. Sig?

-Potential for molecule to be attract electrons -High redox potential = high affinity for electrons -Redox potential is what moves electrons around the ETC A: Helps explain how ETC works

What is cell respiration? Relate to mitochondria. Sig?

-Process where cell generates large amount of ATP from food molecules during cell respiration A: Permits organism to make enough energy to maintain itself

What is ATP synthase? Relate to mitochondria. Sig?

-Protein complex that catalyzes the energy requiring synthesis of ATP from ADP. -Functions like turbine, permitting proton gradient to drive production of ATP A: Help produce the vital cellular component, ATP

Describe molecular mechanisms of electron transport and proton pumping. Relate to mitochondria. Sig?

-Protons are readily moved by transfer of electrons -The redox potential is a measure of electron affinities -Electron transfers release large amounts of energy -Metals tightly bound to proteins form versatile electron carriers -Cytochrome c oxidase catalyzes the reduction of molecular oxygen A: Makes the all important ATP

Describe how activated carriers generated during TCA cycle power production of ATP. Relate to mitochondria. Sig?

-Pyruvate and fatty acids brought into mitochondria, converted to acetyl CoA, acetyl CoA permits TCA cycle, which produces electron carriers that are vital in making ATP A: Produces important electron carriers for making ATP

What are redox reactions? Relate to mitochondrial function. Sig?

-Reactions where electrons are transferred from one species to another -Used in ETC A: Important process for producing ATP

What is the electron transport chain? Relate to mitochondria. Sig?

-Series of electron carrier that are embedded in mitochondrial membrane A: Permit movement of hydrogen atoms that ultimately diffuse and provide energy to phosphorylate ADP, making energy for the cell

Describe how membrane based systems use energy stored in electrochemical proton gradient to synthesize ATP. Describe the two stages. Relate to mitochondria. Sig?

-Stage 1: energy of electron transport is used to pump protons across membrane -Stage 2: energy in proton gradient is harnessed by ATP synthase to make ATP A: Show how cell makes use of varying processes to produce important materials for the cell

What are iron-sulfur centers? Relate to mitochondrial ETC. Sig?

-Structures present in ETC that have low affinity for electrons, permitting the passing of electrons. -Will have negative redox potential as less tendency to hold onto electrons A: Vital for making sure electrons passed down ETC so ATP can be made

Describe the mitochondrial matrix. Relate to mitochondria. Sig?

-The large internal space in the mitochondria within the inner and outer mitochondrial membranes A: Site of ATP synthesis

Describe the intermembrane space. Relate to mitochondria. Sig?

-The narrower space between the inner and outer mitochondrial membranes A: Site of where proton gradient builds

Describe how quinones carry electrons within the lipid bilayer. Relate to mitochondria. Sig?

-Ubiquinone, the quinone in mitochondrial ETC, picks up electrons as it picks up hydrogens, helping to pass along electrons down the ETC A: Assists production of ATP

Describe uncoupling agents. Relate to mitochondria ETC. Sig?

-Uncoupling agents are H+ carriers that can insert into the inner mitochondrial membrane -Render membrane permeable to protons, allowing H+ to flow in without passing through ATP synthase A: Show different mechanisms for ATP synthesis to be regulated

What is oxidative phosphorylation? Relate to mitochondria. Sig?

-Where ATP is made in the mitochondria, requiring a membrane. Depends on electron transport process A: Produces lots of ATP so cell can do lots of things

What is nitrogen fixation? Relate to monomer production. Sig?

-Where organisms reduce N2 to ammonia by adding nitrogen -Helps produce compounds useful in making amino acids A: Shows importance of high energy processes for cells

Describe how the electrochemical proton gradient across the inner mitochondrial membrane is used to drive some coupled transport processes. Relate to mitochondria. Sig?

-pH gradient drives phosphate import, pyruvate import, and formation of ATP A: Shows how proton gradient useful for multiple aspects