electron transport chain& aerobic and anaerobic respiration and fermentation (26)

what occurs during electron transport in the mitochondria

• electrons from NADH and FADH2 pass through membrane-bound complexes(1-4), releasing energy to pump protons into the intermembrane space, creating a proton gradient

what is electron transport chain

• series of memrbane electron carriers, some use energy to move protons out of mitochondrial matrix into the mitochondrial intermembrane space

  • established proton gradient across mitochondrial inner memrbane

what is oxidative phsophorylation

• atp synthesis results from reoxidaiton of electron carriers (NADh and FADH2, to NAD+ to FAD)

what is chemiosmosis

• The movement of protons back into the mitochondrial matrix via ATP synthase

• Driven by the proton gradient, resulting in ATP synthesis

how does free energy change as electrons move through the ETC

• free energy decrease; electrons move from high energy carriers (NADH/FADH2) to lower-energy acceptors, ultimately reducing O2 to H20

what is the function of ATP synthase

• it is a molecular motor that synthesizes ATP from ADP and Pi using the energy of the proton gradient

what experimental evidence supports chemiosmosis

• artificial vesicles with ATP synthase and bacteriorhodopsin produced ATP when exposed to light, proving that a proton gradient alone can drive ATP synthesis

• linkage is indirect

what electron acceptors have the highest redox potential

• oxygen

what has the lowest redox potential

NADH dehydrogenese complex 1

what is redox potential

• ability of a molecule to accept electrons

• molecules pass from a molecule with lower redox potential to one with a higher redox potential

what is UCP1 and how does it affect ETC and ATP synthase

• mitochondrial inner membrane protein found in brown fat cells

• part of the uncoupling protein family

• disrupts the tight coupling between electron transport chain and ATP synthesis

• UCP1 bypasses ATP synthase by allowing protons to flow back into the matrix without generating ATP, but releasing heat

• happens especially in newborns- thermal regulation

what are the net products of glycolysis per glucose

• 2 ATP, 2 NADH, 2 pyruvates

what are the products of pyruvate oxidation ( per glucose)

• 2 NADH, 2 CO2, 2 acetyl CoA

what are the products of the TCA cycle ( per glucose)

• 2 ATP, 6 NADH, 2 FADH2, 4 Co2

what are the products of the ETC - per glucose

• 28 ATp, H20, NAD+, FAD

what is the final electron acceptor in aerobic respiration

oxygen

what are common final electron acceptors in anaerobic respiration

Nitrate (NO₃⁻), sulfate (SO₄²⁻), or other inorganic molecules.

what kind of respiration can Ecoli do

both aerobic , anaerobic and fermentation.

which yields more ATP - aerobic or anaerobic respiration

• aerobic respiration ( 38 vs. 5-36 atp)

what is the purpose of fermentation

• to regenerate NAD+ for glycolysis in the absence of oxygen

what is the role of lactate dehydrogenase in lactic acid fermentation?

• converts pyruvate to lactate and regenerates NAD+

• its a cytosolic enzyme ; bidirectional ( cori cycle)

what is lactic acid fermentation

• regeneration of electron carriers in the absence of oxygen

• happens in bacteria, plants, animals ( mammals)

what is the cori cycle

• the cycle where lactate from muscles is transported to the liver, converted to glucose and returned to muscle

why do muscles hurt after exercise

• immediate soreness is due to lactic acid buildup; delayed soreness ( DOMS) is from microtrauma and inflammation

what enzymes are involved in alcoholic fermentation

• pyruvate decarboxylase ( pyruvate → acetaldehyde) and alcohol dehydrogenase ( acetaldehyde → ethanol)

what are the products of alcoholic fermentation

• ethanol, co2, and NAD+

how much ATP is produced by glycolysis alone

2 ATP (nett

how much ATp is produced by aerobic respiration total

• 38

how much ATP is produced by fermentation

• 2 ATp per glucose ( from glycolysis only)

where does glycolysis occur in both prokaryotes and eukaryotes

• cytoplasm

where does pyruvate oxidation and TCA cycle occur in eukaryotes

• mitochondrial matrix

where does the ETC occur in eukaryotes

• inner mitochondrial membrane ( cristae)

where do all steps of respiration occur in prokaryotes

• cytoplasm ( glycolysis, TCA, fermentation) and plasma membrane (ETC, electron transport chain)

how are catabolic and anabolic pathways interconnected

• catabolic pathways ( glycolysis, TCA) break down molecules to release energy and intermediates which feed into anabolic pathways ( gluconeogensis, amino acid synthesis)

what is the role of key intermediates like acetyl -coa

• they serve as metabolic hubs linking energy production with biosynthesis of lipids, amino acids, and nucleotides