Kiss energy conversinon and metabolic compartmentalization: mitchondria+chlorplast Flashcards
How do bacteria generate energy, what do they create to generate energy?
-what is the energy source for animals vs plants
Bacteria generates energy through having 2 membranes and then creates a potential where they separate and concentrate things to create a gradient and when that gradient is released energy is created.
-This energy (potential and kinetic energy) to generate a chemical energy source -> animals do it via mitochondria and plants do it through chloroplasts
How does energy production in the mitochondrion start (in what cycle/what is produced)?
-In the mitochondrion, energy-rich molecules derived from fat, carbohydrate, or protein degradation are fed into the citric acid cycle.
-This cycle provides electrons to generate the energy-rich compound NADH (electron holder) from NAD+.
After NADH has been produced in the mitochondirion energy productino cycle what happens after? How do we get ATP?
The NADH electrons then flow down an energy gradient in the mitochondrial electron-transport chain, until they combine with molecular O2 and H+ in the final complex to produce water.
-this produces ATP
What does mitochondria use as its energy source vs chlorplast?
-mitchondria uses chemical fuels like fat, carbs, etc
chlorplasts use sunlight
What are 2 parts of the body that have lots of mitochondria
-cardiac muscle and sperm tail
What is the main thing that causes ATP formation in the mitchondria/chloroplasts
-coupling electrons down a concentration gradient allows us to create ATP
What does the mitochondria have in its structure?
Why is the cristae structure important
-it has 2 membranes OMM, and IMM (has folds called cristae)
-cristae has organization of etc and it serves as a cup to collect the protons to create a proton motive force
What is important about mitchondria what events can it undergo?
-it has its own DNA and can undergo fusion and fission events
Why would mitochondria undergo fission?
What is fission?
Where does the part that undergoes fission go?
fission is when the mitchondria gets cut up
-would undergo fission because of oxidative stress to send all of the garbage to one side of the mitochondria and cut it
-cut portion goes to lysosome to be degraded
What is mitochondria fusion?
-they would fuse during cell cycle or to form polymers
What is used in the mitochondria to pinch off some parts?
-what is used as energy for the fission
-dynamin is used to contrict the microtubules and undergo fission to pinch off parts
-dynamin uses GTP as energy
What goes into the citric acid cycle to commence it?
acetyl CoA (2 carbons) is made from amino acid, fatty acid, pyruvate and ketone bodies
What happens when Acetyl Coa goes into citric acid cycle?
What do the enzymatic steps do?S
-citrate synthase combines acetyl CoA (2 carbons) with oxaloacetate (4C) and make a 6 C compound citrate
-after enzymatic steps we lose the 2 C that came in from acetyl CoA, they come out as CO2 and we
regenerate oxaloacetate
What is produced after regenerating oxaloacetate?
What is NADH and FADH2, what is their energy output?
in addition to producing the 2 CO2 we created GTP as an energy source & 2 NADH and 1 FADH2
* NADH is an energy source, FADH2 is a similar reduction equivalent we can derive energy from
* From every NADH we get 3 ATP and every FADH2 we get 2 ATP
What converts pyruvate into acetyl CoA, to do substrate level phosphorylation?
is acetyl CoA gluconogenic?
-PDH (pyruvate dehydrgenase)
-acetyl CoA is not gluconogenic, it cant be converted to go back to glucose form
What process produces ATP?
How does mitchondria particpate in cell signaling and in synthesis of heme and iron?
-Oxidative phosphorylation in mitochondria produces most of the ATP used by eukaryotic cells
-synthesis of heme/iron=These metal-containing components (carrier electrons) are synthesized in mitochondria and play a central role in respiration and other cellular processes
-cell signaling=Mitochondria buffer the concentration of Ca2+, an ion that plays a role in many signaling processes, including muscle contraction
How does mitochondria regulate apoptosis?
How are reactive oxygen species involved in mito.
-Molecules released from mitochondria trigger a proteolytic cascade that leads to cell death
-Although reactive oxygen species can damage macromolecules, they are also involved in signaling
Why is cardiolipin important in mito.
What happens if you dont have cardiolipin?
-cardiolipin is a diphosphatidylglycerol which is useful since it helps bring ETC complexes together
-the complex doesnt stack together and you dont get efficient energy production
What is the proton motive force (where do we take the protons from/move them to)?
-take proton from matrix and move it into the inter membrane space, conc the protons in the
intermembrane space, let them back w the gradient to harness that movement to make ATP
(couple proton movement back w ATP production)
What is the first electron donor and the last electron acceptor in redox?
-first donor=NADH
-last acceptor=oxygen
What does an iron sulfur cluster hold?
-they hold one electron
What is the steps 1 and 2 through the 3 respiratory chain proton pump?
1.1. NADH donates electron and as it is passed around in complex 1, 1 proton is released to the inter mitochondrial space
2. Now electron passes over complex 2 (this is where FADH2 offloads its electron) to complex 3
What is the steps 3 and 4 through the 3 respiratory chain proton pump? (what happens in complex 3 and 4)
3.complex 3 pumps out a proton and passes the electron to cytochrome C and then to complex 4
4. as it goes through complex 4 another proton is released, electron is then given up by cytochrome C to where oxygen is the terminal acceptor and we generate water
How many protons does NADH generate vs FADH?
How many protons does each complex make?
NADH generates 10 protons since it starts at complex 1
FADH generates 6 protons since it starts at complex 3
-complex 1 and 3= 4 protons each
-complex 4=2 protons
what is the chemical formula for 1 molecule of glucose breakdown?
C6H12O6 + O2 = 6CO2 + 12H2O
What is the point of ETC?
-it optimizes energy transport of electrons to make energy
What is the structure of complex 4, what are the electrons passed through to go into?
-What is the difference in this compelx vs complex 1 in terms of where electrons get passed
electrons passed through cytochrome C to the iron mol (heme) (in complex 1 it is iron surfer clusters and in complex 4 it is heme groups -> so the electrons get passed to hemes) the hemes are able to pass the electrons to the oxygens
What is different about when FADH2 enters the ETC cycle (what does it bypass, where does it donate its electrons and what is its production)?
when FADH2 joins it shares electrons at complex 2, by passing complex 1.
-Then the 2 electrons FADH2 donates goes from complex 2 to 3, at complex 3 it pumps the 4 protons, and moves to complex 4 to pump 2 protons.
-Totalling 6 protons which we can make 2ATP
How does NADH in the ETC differ from FADH2 in its production and where the electron starts?
Where the electron gets passed?
Complex 1 transfers electron from NADH to iron sulfur clusters to ubiquitinone, then complex 3 via cytochrome C,
-then cytochrome C reductase transfers the electron to complex 4
-NADH donates 2 electrons to complex 1. As the electrons move from acceptor to acceptor those
electrons pump 4 protons out of complex 1, then they move to complex 3 pumping 4 more protons,
then at acceptor 4, 2 more protons pumped.
-Thus 10 protons pumped via 2 electrons. It takes 3
protons to make 1 ATP -> thus 3 ATP each time
Why is the concentration of glucose in the cell almost 0?
How does glucose get converted into glucose 6-phosphate in glycolysis?
Step 1: hexokinase converts glucose to glucose 6-phosphate (occurs directly when it enters cell to energize it and trap it so it no longer fits into the transport channel and remains in the cell)
* Conc of glucose inside the cell is almost 0 bc it lost immediately gets trapped inside the cell as glucose 6-phosphate (reversible reaction)
In the 2nd step of glycolysis what happens when we break fructose? what is it broken into?
Step 2: # of steps happen to add 2 phosphate groups and we break fructose into two 3C compounds to generate pyruvate.
Glucose -> pyruvate + 2NADH + 2ATP (substrate level phosphorylation)
What happens in the mitochondria after glycolysis is complete in the cytosol, what gets converted?
Where does the acetyl CoA go/get put into?
What is produced from this acetyl CoA/cycle
- pyruvate dehydrogenase converts the 2 pyruvate into acetyl CoA and 2 more NADH
-Step 4: now the acetyl CoA is put into the citric acid cycle where it is converted to 6NADH, 2 FADH, and 2 GTP (can also say ATP), along with the original 2ATP and 2 NADH. Totalling 8 NADH, 2FADH2, 2GTP, 2ATP
What is allostery? What occurs in allostery, what is activated and when?
=product binds to enzyme and affects its activity,
-PDH is activated when CoA levels are high and NAD levels are high, means we do not have enough NADH (energy) so there is more needed in pathway
What does it mean when cyclic AMP levels are high?
What can inhibit this process?
-AMP levels are high this indicates that energy levels are low -> thus pump CoA through the pathway.
-Inhibition of this process is acetyl CoA as it is the product (acetyl CoA inhibits pyruvate dehydrogenase.
-If all NADH there are no acceptors
available thus the pathway wont proceed. Fatty acids themselves (too many we do not need more Acetyl CoA)
What are the components involved in allosteric activtaion vs inhibition, what levels are high in each?
-activation=when CoA, and NAD+ levels are high, pyruvate, AMP, and Ca2+
inhibition=acetyl CoA (PDH), fatty acids (FAs), NADH, ATP
What are the net products of glycolysis?
in the cytosol (glycolysis) vs in mitochondria (PDH and citric acid cycle)
WHat is the total count from 1 glucose moleucle?
in cytosol=1 glucose=2 pyruvate+2NADH+2 ATP
in mitochondria:
2 pyruvate–>2 acetyl CoA+2NADH
2 acetyl CoA–>6 NADH+2FADH2+ 2GTP
Net result: 2 pyruvate–>8 NADH+2 FADH2+2 GTP
total: 38 ATP
10 NADH–>30 ATP
4 ATP
2 FADH–>4 ATP
What is the net result in mitochondrion from oxidation of palmitoyl CoA?
1 palmitoyl CoA–>31 NADH+15 FADH2+8 GTP
-fatty acid so we get lots of energy
What is the first step of the citric acid cycle, what is put into the cycle and what generated it?
How many carbons does each component have?
-Acetyl CoA, generated by pyruvate dehydrogenase, formed w oxaloacetate to create citrate
-Oxaloacetate has 4C and acetyl CoA has 2C and if we put then tg we create a 6 C citrate then we lose 2 CO2 (2C from acetyl CoA)
How much carbon is left in citric acid/krebs cycle when we lose 2 CO2?
How much of each prodcuct do we create in the end?
4C of oxaloacetate are left and we recycle them, this process generates a bunch of energy forms
(3NADH and, 1 FADH, 1ATP ->substrate level phosphorylation)
* every glucose we get 2 acetyl CoA thus it is all doubled so 6NADH,2ATP, 2FADH
What does equlibrium tell us?
-takes into account temperature to account for adjustment factor from delta G compound to be delta G prime
-if we are equilbrium then delta G = delta G prime
What is the cristae good for? what is at the end of cristae?
good for a microenvironment where we can concentrate the protons and at the end of the
cristae we have the ATPase: so we channel the protons to synthesize ATP
What happens when light comes into a chlorplast?
What does it trap and drive?
Where does the electron come from, what can they use ATP for?
light comes in and binds to the thylakoid membrane of the chloropltast that activates (via an electron) -> it traps the electron and uses it to drive the proton pump and create a gradient which can be harnessed to generate ATP
* Electron come from sunlight instead of oxidative sources
* They can use ATP them selves or to drive carbon fixation (sugar formation)–> starch
What is the enzyme that CO2 uses for carbon fixation?
What does it bind and create, why is it important?
take carbon dioxide and uses specialized enzyme rubisco (it is the most imp enzyme for carbon fixation in plants),
-takes CO2 and binds it to sugar to create the intermediate which becomes a utilizable intermediate of the glycoglucogenic pathway (it can be converted into glucose and be stored as a starch)
* Imp enzyme bc this enzyme fixes the CO2 into sugar
What does light do and generate in plants?
Where is ATP/sugar generated
comes in and traps electrons to generate ATP for carbon fixation
-ATP/sugar is generated in the leaves
