Ch. 3 - Cellular Respiration Flashcards
___ is entry of air into lungs and gas exchange between alveoli and blood; ___ is exchange of gas between blood and the cells + intracellular respiration processes
___
external respiration
internal respiration
During respiration, high energy H atoms ___ from organic molecules (___)
removed
dehydrogenation
Aerobic respiration = in the presence of O2 (glycolysis, pyruvate decarb, krebs cycle, oxidative phosphorylation); ___ is
the final product
water
Glycolysis – decomposition of glucose into pyruvate in ___
o 2ATP ___, ___NADH produced, ___ATP produced, 2 pyruvate formed NET: 2ATP+ 2NADH+ 2pyruvate (+2H2O+2H+)
o ATP produced here via ___
Direct enzymatic transfer of a ___, no extraneous carriers needed
o Hexokinase phos’s glucose, important because then it can’t diffuse out + tricks the gradient
o PFK (enzyme) adds \_\_\_, makes fructose 1,6-biphosphate – this is \_\_\_ and commits to glycolysis, major regulatory point!
cytosol
added
2
4
substate-level phosphorylation
phosphate to ADP
2nd phosphate
irreversible
Pyruvate Decarboxylation
o At this point we are in the ___
o Pyruvate to Acetyl CoA, producing ___NADH and ___CO2
NET:2NADH+2CO2
o Catalyzed by PDC enzyme (___)
mitochondrial matrix
1
1
pyruvate dehydrogenase complex
Krebs Cycle/Citric Acid Cycle/Tricarboxylic Acid Cycle - fate of pyruvate that is produced in glycolysis
o **In the Krebs cycle, Acetyl CoA merges with oxaloacetate to form ___, cycle goes w/ ___ intermediates
o ___ NADH, ___ FADH2, ___ ATP (via ___), and ___ CO2 are produced per turn
o x2 for glucose because 2 pyruvate are made from 1 glucose in glycolysis so two rounds of TCA cycle occur
Total 6 NADH, 2 FADH2, 2 ATP (technically GTP), 4 CO2 These ATP produced via ___
o takes place in ___ (likewise with pyruvate decarbox)
o CO2 produced here is the CO2 animals ___
citrate
7
3 1 1 sub. phos. 2
sub. phos
mito matrix
exchale when they breathe
ETC (electron transport chain)
o Takes place at the inner ___ (folds which increase ___ for more ETC action)
inner membrane/cristae
SA
Oxidative Phosphorylation – process of ADP->ATP from NADH and FADH2 via passing of electrons through various carrier proteins; energy doesn’t accompany the phosphate group but comes from the ____ in the ETC establishing an ____ that supplies energy to ATP synthase
oNADH makes more energy than FADH2, more H+ is pumped across per NADH (both are coenzymes) (3:2 yield)
Final electron acceptor is ____ – combines with native H+ to form water (H2O)
Random note: oxidizing agent causes ____ to get oxidized; the oxidizing agent itself is ____; vice versa for reducing agents
o Carriers extract energy from NADH and FADH2 while pumping protons into the intermembrane space – atp synthase uses this gradient (which is a pH and electrical gradient) to make atp as it shuttles H+ back into the ____
o Coenzyme Q (CoQ)/Ubiquinone is a soluble carrier dissolved in the membrane that can be fully reduced/oxidized, it passes electrons as seen in diagram
o Cytochrome C is a protein carrier in the ETF, common in many living organisms, used for genetic relation Cytochromes have nonprotein parts like ____ (donate/accept electrons, for redox!)
o Couples ____ of electrons with ____ of protons across cristae membrane
____
electrons
proton gradient
oxygen
something else to get oxidized
reduced
inner matrix
iron
exergonic flow
endergonic pumping
TOTAL energy from 1 glucose is ~___, but in prokaryotes 38 ATP (not actual yield, mitochondrial efficacy varies)
o Difference because prokaryotes have no ___ so they (unlike eukaryotes) don’t need to transfer pyruvate into the ___ (which is done via ___ thus costing ___), they use ___ for respiration.
___
36
mitochondria mitochondrial matrix active transport ATP cell membrane
Mitochondria – outer membrane, intermembrane space (___), inner membrane (___), mitochondrial matrix (___)
H+
ox. phos.
krebs
Chemiosmosis in mitochondria:
o Mechanism of atp generation that occurs when energy is stored in the form of a ___ across a membrane
o Krebs produces NADH/FADH2, they are ___ (lose electrons), H+ transported from ___ to intermembrane space, pH and electric charge gradient is created, ATP synthase uses the energy in this gradient to create ATP by letting the protons flow through the channel
o Common question topic is about pH changes from these processes; remember that H+ cxn up means ___!
proton concentration
oxidized
matrix
pH down
ATP (adenosine triphosphate) – an ___ (due to its ribose sugar)
___ molecule because the 3 phosphates in ATP are negatively charged and ___
o When one phosphate group removed via ___, more ___ molecule ADP results
o The change from less stable molecule to more stable always ___ energy
Provides energy for all cells by transferring phosphate from ATP to ___
RNA nt.
unstabe repel one another hydrolysis stable releases
another molecule
Anaerobic Respiration (___) –
Includes ___ + ___
Aerobic respiration regenerates NAD+ via O2, which is required for continuation of ___, without O2, there would be
no replenishing – ___ accumulates, cell would die w/ no new ATP, so fermentation occurs…
**Alcohol Fermentation
o Occurs in plants, fungi (e.g. yeasts), and bacteria (e.g. botulinum)
o Pyruvate -> acetaldehyde + CO2, then acetaldehyde -> ___ (and NADH -> ___).
o Acetaldehyde is the final ___! The final molecule isn’t the final acceptor; acetaldehyde is the final acceptor of the electrons thus forming
ethanol! Same with ___ being the final electron acceptor of cellular respiration; thus forming H2O!
cytosol glycolysis fermentation glycolysis NADH
ethanol
NAD+
electron acceptor
O2
anaerobic resp. (cytosol)
**Lactic Acid Fermentation
o Occurs in human muscle cells, other microorganisms
o Pyruvate -> ___ (and NADH -> NAD+)
o Lactate is transported to liver for conversion back to ___ once surplus ATP available
lactate
glucose
anaerobic resp. (cytosol)
___ anaerobes can use oxygen when it’s present (more efficient) but switch to fermentation/anaerobic respiration if ___;
obligate anaerobes ___ in presence of oxygen
facultative
it isn’t
cannot live
