BICD110_SS209_PS3_key - Q1 The electron transport chain...

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Unformatted text preview: Q1: The electron transport chain takes electrons initially from what molecule and finishes by donating them to what molecule? Q1 Answer: NADH donates the electrons and O2 accepts the electrons Q2: When electrons are transferred to enzyme complexes further along in the electron transport chain, how is the energy released used to pump protons across the inner mitochondrial membrane? Q5 Answer: The electronic interactions created by electron transport drives allosteric conformational changes in the enzyme allowing for protons to be pumped across the membrane Q3: Write out the path of electron flow for the electron transport chain. Which two intermediates are not enzymes? Which is not a part of a protein? Q3 Answer: NADH --> NADH dehydrogenase complex -->ubiquinone ->cytochrome b-c1 complex -->cytochrome c -->cytochrome oxidase complex ->O2 Ubiquinone and Cytochrome c are not enzymes. Ubiquinone is not part of a protein. Q4: ATP Synthase is found both in mitochondria and chloroplasts. What component of the electrochemical proton gradient is most important for ATP synthesis in each organelle? Q4 Answer: The electrical gradient provides the majority of the driving force in both mitochondria and chloroplasts. Q5. Name each structure of the chloroplast Q5 answer 1. outer membrane 2. intermembrane space 3. inner membrane (1+2+3: envelope) 4. stroma (aqueous fluid) 5. thylakoid lumen (inside of thylakoid) 6. thylakoid membrane 7. granum (stack of thylakoids) 8. thylakoid (lamella) 9. starch 10. ribosome 11. plastidial DNA 12. plastoglobule (drop of lipids) Q6 . What gradient does the ATP synthase use to generate ATP from ADP and how is that gradient generated in the chloroplast? Q6 answer ATP synthase uses H+ gradient, which is formed by the oxidation of water molecules and plastoquinone on one side of the membrane and the reduction of NADP to NADPH on the other side of the membrane. Q7) What is the definition of a dominant negative protein? Explain how a dominant negative receptor tyrosine kinase demonstrated that dimerized receptors undergo cross phosphorylation as opposed to self-phosphorylation. Q7: dominant negative protein is a protein in which the mutant phenotype is observed even when the genotype is still heterozygous of one wild type allele and one dominant mutant allele. That is, the mutant allele is dominant over the wild type allele. In RKT, when you experiment with one wild type and one mutant allele, the mutant domain was stil lphosphorylated while the wild type domain was not phosphorylated. This indicates that the wild type domain was still able to phosphorylate the mutant domain but the mutant allele was no longer catalytically active and thus was unable to phosphorylate the target wild type receptor. Q2: Explain the difference between smoothly-graded an switch-like signaling. A2: Smoothly graded signaling produces response level proportional to the concentration of signal molecule. Switch-like signaling produces reponse when and only when the the concentration of signal molecules reaches a threshold level, "all-or-nothing" response. Q3: To amplify an extracellular signal, signal molecule receptors on the plasma membrane are commonly coupled to 3 types of protein that would trigger a cascade for signal amplification. Name the 3 types of protein and give an example for each. A3: Ion channel-coupled: acetylcholine receptor G-protein coupled: olfactory receptor Enzyme-coupled: tyrosine kinase Q10: Fill in the table regarding the different types, components, and functions of G-Protein Coupled Receptors Type: G-Protein GEnergy Gα - GT P 2nd D ow n R eg. Gstimulato ry Coupled Receptor Struc ture: 7 TM protein of one single polypeptide Proteins: Hint: 3 Subunits Gαs Gβs Gγs requiring pr oc es s ? Yes; Gαs =GTPase Effec tors Adenyly l Cyclase (AC) Msngrs Produced cAMP stream r es pons e Activates PKA ( Pi) many dow n stream proteins proteins R GS : Gα regulator CREB: cAMP regulator PD E: cAMP regulator β ARK: ( P i) receptor, Arrestin can bind. R GS : Gα regulator CREB: cAMP regulator β ARK: ( P i) receptor, Arrestin can bind. Calmodul in N eeds ++ Ca to regulate proteins throughou t the cell Ginhibitory 7 TM protein of one single polypeptide Gαi Gβi Gγi Yes; Gαi =GTPase AC Inhibited cAMP productio n Inhibits AC, no cAMP, no downstrea m r es pons e Gq 7 TM protein of one single polypeptide Gαq Gβq Gγq Yes; PI PIP2, req. 2ATP PLC Ca ++ Cleaves PIP2 into IP3 and DAG. IP3 goes onto the cytoplas m w her e i t binds channels on the ER and releases ++ Ca , D AG stays in the membrane ...
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