Cellular Respiration Flashcards
NADH to membrane
Goes to mythochindria membrane, meets a more electronegative atom, NADH looses its h (oxidized) and H will travel down carriers until it meets oxygen
All to create a proton gradient which will help in creating atp
If no oxygen, no electron transport, carriers will be reduced until the chain is blocked (all carriers are reduced)
Fermentation
To oxidize NADH without oxygen, we reduce acetaldehyde into ethanol
Whole point is to be able to continue glycolysis in the absence of oxygen
Not efficient way to use fuel
Humans do lactic acid fermentation, accumulation of lactic acid causes muscles ache
Electron transport chain purpose
To create a protein gradient, endergonic processe
At 3 places, carriers are bonded to proteins to form multi protein complexes to do work of pumping protons against the gradient to the intermembrane space
Energy source of this pumping is the electrons moving down the gradient
How: some carrier will accept and release H along with electrons, while others only transport electrons, causing H+ to be released back into the surrounding solution
Because of size difference between cell and mitochondria, the protons have to be pump into the intermmebrane in order to create a gradient
FADH2
Will synthesize less atp because it drops its electrons lower down the electron chain
Atp and electron transport
Reverse of ion pumps,
Uses gradient to make ATP
Particles moving down abrading release energy
Chemiosmosis
Ion gradient used to drive cellular work like synthesizing ATP
ATP synthase
Found on inner mitochondrial membrane
Enzyme uses H+ gradient to make ATP,
Rotor within the membrane spins when H+ flows,
Stator is anchored in the membrane holds knob
Rod extending into the knob also spins a little, activating catalyst in sites on the knob
3 catalytic sites in the knob join inorganic phosphate to ADP to make ATP
F0 and axial rotate (in mitochondria) , causing F1 (in membrane) to change conformation
F1ATPase changes conformation to produce atp
When rotates clockwise, produces ATP, when anticlockwise, hydrolyses ATP to make adp
Substrate level phosphorylation
Only occurs in a couple places
Produces atp directly using an enzyme
Very little produces this way as not enough enzymes and not very efficient, rest of atp is produced in oxidative phosphorylation
Cryterylaze
Lines in mitochondria to form intermembrane
Glycolysis
Splitting of sugar
Done in cytoplasm, produces two ATP by substrate level phosphorylation
Glucose oxidized into pyruvic acid
9 chemical steps to not explode the cell, series runs twice
Energy investment phase (2 atp needed)
Energy payoff phase (4 atp produced)
Net (2 atp, 2 NADH, 2 pyruvic acid)
We don’t have that many enzymes to do all atp that way
Most energy still in pyruvic acid
Must have a way to replenish its supply of NAD+ as it is reduced to NADH, so fermentation
Energy investment stage glycolysis
Atp invested to add phosphate group on glucose (1st step)
Isomerization enzyme=isomerase (G6P into isomer fructose 6-phosphate)
2nd atp is used for another phosphorylation (PFK enzyme)
fructose 6-phosphate turned into fructose 1,6-biphosphate
And immediately spilts into 2 3-carbon molecules (G3P)
Energy pay off stage glycolysis
addition of phosphate group coupled with redox (G3P oxidized, NAD reduces)
Substrate level phosphorylation produces ATP
Chemical rearrangement
Water is removed, causing the phosphate bond to become high energy
Atp is produced by substrate level phosphorylation, pyruvate is product
NADH go to mitochondria to deliver H in order to pump proton and produce ATP
Step 1 glycolysis
Glucose enters the cell through facilitated diffusion
Phosphate attaches to glucose in order to maintain the gradient (uses 2 atp)
In the first reaction of glycolysis, the enzyme hexokinase rapidly phosphorylates glucose entering the cell, forming glucose-6-phosphate (G-6-P). uses ATP (endergonic)
Goal fermentation
Oxidize NADH and get back NAD+ without oxygen
Feedback inhibition
To regulate the supply and demand aspect of metabolism
End product of the anabolic pathway accumulates enough and inhibits the enzyme that catalyze early steps of the pathway
Happens when you have enough of something
Control regulates activity of enzymes at strategic points in catabolic pathway through allostreric regulation (regulation PFK)
Work and atp
ATP into Adp + pi + energy
More work done so atp concentration goes down
Cellular respiration speeds up
Atp more sufficient for demands now
Cellular respiration slows down to spare valuable organic molecules
regulation of PFK enzyme
Allosteric regulation
Site other than active site of enzyme
Regulator binds there and stabilization in active or inactive form
Ratio between ADP and atp will determine if the enzyme phosphofructokinase is activated or not (adp and citric acid is an activator of PFK, ATP is an inhibitor)
Kerbs cycle
in matrix of mitochondria
8 steps
4 redox reactions (3-4-6(FADH)-8)
Citrate first product
steps:
Acetyl CoA, coenzyme A leaves, will produce Citrate
Redox, produces 5-carbon-compound, NADH and CO2
redox, produces 4-carbon-compound, NADH and CO2
ATP produces
Redox (FADH)
Redox, produces NADH and oxaloacetate
Diffusion pyruvate
Pyruvate enters outer membrane through facilitated diffusion and the inner membrane Pyruvate/H+ symport carrier protein (dependent on H gradient created through electron transport chain)
H moves down the gradient
Caused by electron transport chain
Without gradient, no pyruvate movement
Energy per glucose in kerbs sucked
2 atp
6 nadh
2 fadh2
(1 acetyle does half of these)
From all these electrons, , h will be dropped and 34 atp will be produced
Per NADH 3 atp
per FADH2 2 atp
About 38 atp (theoretical, maximum without any atp spending)
Fermentation in humans
Moderate exercise, muscles use o2=aerobic exercise. Is vigorous but slow enough that the blood can deliver o2 to the muscles at least as fast as they use it
Strenuous exercise= muscles use o2 too fast, cells will become anaerobic. Produce lactic acid,makes muscles ache
Stech after and before to get lactic acid back to liver, where it’s converted back to puruvate
Strict anaerobes
Some microorganisms only metabolize in anaerobic conditions
Oxygen is toxic to these organisms they are strict anaerobes
Dinitrial fenil DNP
Uncouplers
Weight loss medication
Makes membrane permeable to H ions, making you use more glucose for the same amount of ATP
As more glucose is used, more energy is lost into heat so you cook from the inside
Stages of cellular respuration
glycolysis
krebs cycle
electron transport chain and oxidative phosphorylation
phosphofructokinase
Enzyme phosphofructokinase enzyme used to produce fructose-1,6-diphosphate from fructose-6-phosphate (PFK)
respiratory poisons
Cyanide poisons the mitochondrial electron transport chain within cells and renders the body unable to derive energy (adenosine triphosphate—ATP) from oxygen. 4 Specifically, it binds to the a3 portion (complex IV) of cytochrome oxidase and prevents cells from using oxygen, causing rapid death.
grooming pyruvate before krebs cycle
Carbonyl group of pyruvate is released as 1 molecules of CO2 per pyruvate (diffuses out the cell into blood for transport to the lungs, decarboxylation reaction)
remaining is oxidized into acetate by enzyme transferring 2 electrons to NAD+
Co-enzyme A attaches by an unstable bond, making it very reactive
Acetyle CoA can now eneter krebs cycle
Total net of NADH and ATP
2 NADH in susbtarte level phosphorylation
2 NADH in oxidative decarboxylation of pyruvate
6 NADH and 2 FADH2 in krebs
net of about 34-38 ATP total
Rotenone
Blocks second carrier
Carbon monoxide
Blocks second to last carrier
Oligomycin
Blocks atp synthase
