Use Ch. 9-10 in \"Campbell Biology\" Pearson book by Urry, Cain, Wasserman, Mino
ID: 270989 • Letter: U
Question
Use Ch. 9-10 in "Campbell Biology" Pearson book by Urry, Cain, Wasserman, Minorsky, and Reece. Write in multiple paragraph form. Please be detailed. Include vocabulary listed below question.
4) Question: Diagram and describe how uncoupling proteins work, including their effects on cellular respiration. Explain how these proteins might play a role in thermogenesis and the control of reactive oxygen species such as superoxide. (Hint: you’ll need to explain the ETC and proton gradient for this.)
Important Concepts
Respiration (Chapter 9)
The Hindenberg analogy: what is a redox process, and what makes it exergonic?
Glycolysis:
Where does it happen (in eukaryotes and prokaryotes)?
What is the energy investment phase? Why is it important?
When glucose (or its product) gets oxidized, what is the oxidizer? What gets reduced?
ATP made by substrate-level phosphorylation
Pyruvate
Kinases
Isomerases
Dehydrogenase & oxidation
Phosphofructokinase is allosterically regulated as part of a feedback inhibition system
Why is glycolysis considered to be an ancient pathway?
Mitochondrial transport proteins:
Porins
Pyruvate/OH- exchanger
ATP/ADP translocase (exchanger)
Phosphate/OH- exchanger
Electron shuttles (the book shows 2, but in the lecture I showed a detailed diagram of the FADH2 shuttle only.
Before the citric acid cycle:
COO- becomes CO2
Acetyl CoA and the CoA cycle
Citric acid (Krebs) cycle:
Where does it happen (in eukaryotes and prokaryotes)?
Acetyl in, CO2 out
Why it’s a cycle
NADH, FADH2, ATP produced
Why does the citric acid cycle stop if no O2 is present?
Complex II is attached to the membrane; compare this to the book’s citric acid cycle diagram. Why does this matter?
Electron transport chain & ATP synthase:
Electrochemical proton gradient. It's also a pH gradient.
Where electrons come from & where they go.
What is the energy source for making the proton gradient? Where do the protons come from?
NADH & FADH2, as oxidizers and as reducers. For each redox step in respiration, what gets oxidized & what gets reduced? What’s more electronegative?
Why is O2 needed? Could there ever be an electron transport chain without O2?
Structure of mitochondrion: inner & outer membranes, intermembrane space, matrix
How ATP synthase works
Why 1 NADH is worth more than 1 FADH2
Why 1 NADH is worth more than 1 ATP
Why is ATP better for energy transfers, while glucose is better for energy storage?
Metabolic poisons (drugs that alter ETC/proton gradient). Imagine a drug that blocks the normal function of one of the proteins or of the inner mitochondrial membrane itself. How would the drug affect other parts of cellular respiration such as O2 consumption, NAD+ and NADH levels, rates of glycolysis and citric acid cycle, etc.?
Respiration: how foods other than glucose are used
How other metabolic pathways (including autophagy and anabolic pathways) relate to respiration
Feedback inhibition in regulating respiration. How is the rate of ATP production controlled?
Evolution of proton gradients, e- transport chains, & respiration:
How do prokaryotes do respiration?
What advantage do prokarytes have in respiration?
ATP synthase is also an ATPase. Why? How is this connected to the evolution of cellular respiration?
Uses of proton gradient aside from making ATP.
Uncoupling proteins
UCP1 & brown fat. How is the heat generated?
UCP2 & superoxide. How & where is superoxide formed? Why do reactive oxygen species (ROS) matter?
How does UCP2 help prevent ROS formation?
What is bad about ROS? How can increasing ROS formation extend lifespan in nematodes?
Compare & contrast UCP 1 & 2. What causes each of these channels to open?
How do uncoupling proteins affect metabolic rate, O2 use, NAD+/NADH, etc.? How is UCP1 similar to dinitrophenol (DNP)? How is it different?
Cancer cells: cellular respiration and fermentation
Why would cancer cells preferentially use fermentation over cellular respiration? Why is there a tradeoff between biosynthesis and ATP generation?
What is ectopic ATP synthase? “Combination therapy targeting ATP synthase and 26S proteasome induces ER stress in breast cancer cells.” What does this mean? Why would it work?
Fermentation (Ch. 9):
Why respiration needs O2
Why is glycolysis possible without O2, but not the citric acid cycle or ETC?
Why does fermentation happen in your muscles?
Regenerating NAD+. Why is this important?
Eliminating pyruvate: how is it achieved in fermentation and in respiration, and why is it important?
Photosynthesis (Ch. 10):
How did photosynthesis change the earth? How is this related to the origin of eukaryotes?
Chloroplast structure: inner & outer membranes, thylakoids, stroma
Chlorophyll absorbs light energy… why isn’t this energy released as fluorescence?
Light reactions:
Photosystem structure & function
Resonance transfer vs. electron transfer in photosystem. Why is it important that the chlorophylls are grouped together in a big ring?
Splitting water: a redox reaction. Exergonic or endergonic?
Electron transport chain & ATP production. Does photosynthesis produce a net gain of ATP?
Noncyclic vs. cyclic e- flow. Where do the e- come from in each case? Why does each exist? What makes the chloroplast switch from one to the other?
Inputs & outputs of light rxns. What do the outputs get used for?
Why would ROS formation occur in the light reactions? How do chloroplasts limit ROS formation?
Calvin cycle:
Inputs & outputs. What outputs from the Calvin cycle become inputs in the light reactions?
What gets oxidized, what gets reduced
Rubisco. What is a carboxylase?
Compare & contrast photosynthesis vs. respiration, including a detailed comparison of electron transport chains. Why are they so similar?
Photorespiration:
Why it occurs
How is photorespiration detrimental to plant growth? How could it be beneficial to plants?
How does photorespiration affect the thylakoid proton gradient? What happens to the products of the light reactions?
C4 pathway. C4 does two things to prevent photorespiration.
CAM. Why is it used in succulent plants?
Rubisco vs. PEP carboxylase
Why don’t all plants use CAM or C4?
Explanation / Answer
Answer:
During normal respiration process reduced equivalents ( NADH and FADH2 )formed in glycolysis and TCA cycle are oxidized in electron transport system. As the electrons from these reduced equivalents are transferred through a series of electron carriers to the final acceptor- O2, the protons are simultaneously pumped into the intermembrane space of the mitochondria. This builds proton gradient between the matrix of the membrane and the intermembrane space. The protons in the intermembrane can be conceived as water stored in a dam. These protons carry proton motive force which pass through the ATP synthase into the matrix generating ATP from ADP and Pi.
In hibernating animals, brown fat cells help in maintaining body temperature more than the surroundings. The inner mitochondrial membrane contains a channel protein called the uncoupling protein that allows protons to flow back down their concentration gradient without generating ATP. Activation of these proteins in hibernating mammals results in ongoing oxidation of stored fuel stores (fats), generating heat without any ATP production.
Mitochondria can produce a large part of the total ROS made in cells. Uncoupling process lowers proton gradient, decreases the degree of reduction in the electron transport chain and thus will reduce reactive oxygen species production from the electron transport chain.
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