Chapter 8 Vocab Flashcards
what are exergonic metabolic pathways?
pathways that release free energy that is capture by the cell
what are the three metabolic pathways?
aerobic cellular respiration, anaerobic respiration, and fermentation
which two metabolic pathways do not require oxygen?
anaerobic and fermentation
what is aerobic respiration?
when catabolic processes convert energy of nutrients to store in ATP
why do cells use aerobic respiration?
to obtain energy from glucose; requires oxygen and nutrients are catabolized into CO2 and H2O
what is the equation for the redox reaction aerobic respiration?
C6H12O6 + 6 O2 + 6H2O –> 6 CO2 + 12 H2O + energy
In aerobic respiration what is reduced and what is oxidized?
glucose is oxidized and oxygen is reduced
what happens to free energy during aerobic respiration?
changes in free energy
during aerobic respiration, glucose is broken down slowly to make
36-38 ATP
What are the four stages of Aerobic respiration in order?
glycolysis, formation of acetyl CoA, citric acid cycle, and electron transport chain
what are the reactions involved in aerobic respiration?
dehydration, decarboxylation, preparation reaction, and phosphorylation
what is dehydration?
2 H’s are transferred to NAD+ or FAD
what is decarboxylation?
part of a carboxyl group (COOH) is removed as a molecules of CO2
what is a preparation reaction?
molecules are rearranged to undergo further dehydrogenations or decarboxylations
what is phosphorylation?
the transfer of a phosphate group, may be substrate level, or oxidative phosphorylation
which two methods produce ATP (phosphorylized ADP)
substrate level phosphorylation and oxidative phosphorylation
what is substrate level phosphorylation?
a phosphate group is transferred directly from an organic molecules to ADP
what is oxidative phosphorylation?
the transfer of phosphate group to ADP is due indirectly to the oxidation of NADH and FADH2
where does glycolysis occur?
the cytoplasm
which stages of aerobic respiration occur in the mitochondria?
formation of Acetyl CoA, citric Acid Cycle, and Electrons Transport Chain
what is glycolysis?
6 carbon glucose is metabolized into 2 3 carbon pyruvate ; net yield is 2 ATPs and 2 NADH, no oxygen required
what are the two phases of glycolysis?
endergonic reactions (require ATP) and exergonic reactions (yield ATP and NADH)
what occurs during the first phase of glycolysis?
energy input phase; phosphate groups are transferred from ATP to glucose in two separate phosphorylation reactions, phosphorylated sugar is broken into G3P
first phase of gylcolysis equation
glucose + 2 ATP –> 2 G3P + 2ADP
what occurs during the second phase of glycolysis?
energy capture phase; G3P are converted to pyruvate by oxidizing G3P and ATP is formed by substrate level phosphorylation
NAD+ + 2H –> NADH + H
Overall equation for the second phase of glycolysis
2 G3P + 2 NAD+ + 4ADP –> 2 pyruvate + 2 NADH + 4 ATP
what happens once pyruvate enters the mitochondrial matrix?
pyruvate undergoes oxidative decarboxylation (CO2 diffuses out of the cell) and the 2 carbon fragment is oxidized and attached to coenzyme A yielding acetyl CoA, NAD+ is reduced
overall equation for the formation of acetyl CoA
2 pyruvate + 2 NAD+ +2 CoA –> 2 acetyl CoA + 2 NADH + 2 CO2
what are the two other names for the citric acid cycle?
TCA cycle (Tricarboxylic acid) and the Krebs cycle
what occurs during the citric acid cycle?
acetyl CoA transfers its acetyl group (2 carbon) to oxaloacetate (4 carbon) to form citrate (6 carbon)
the overall equation for the citric acid cycle
oxaloacetate + Acetyl CoA –> citrate + CoA
citrate goes through a series of chemical reactions and loses?
Two carboxyl groups as CO2
net yield of glycolysis
2 Pyruvate
2 NADH
2 ATP
net yield per glucose?
4 CO2 + 4 NADH
what happens during the second half of the citric acid cycle?
4C molecule is rearranged to reform OAA
what happens during stage four of aerobic respiration? (refer to slide 35 for more detail)
NADH and FADH2 from stages 1-3 are used to make ATP by oxidative phosphorylation
what is the electron transport chain coupled to?
ATP synthesis
what is the ETC in eukaryotes?
electron carriers embedded in the inner mitochondrial membrane
what are the four stages of the ETC?
complex 1, complex 2, complex 3, and complex 4
where does the ETC transfer electrons from?
from NADH and FADH2 to Oxygen
what does complex one of the ETC do?
accept electrons from NADH
what does complex two of the ETC do?
accept electrons from FADH2
what happens during complex 3 of the ETC?
accepts electrons from reduced ubiquinone and passes them to cytochrome c
what happens during complex 4 (cytochrome c oxidase)?
accepts electrons from the cytochrome c and reduces O2, forming H2O
what is the final electron acceptor in the ETC?
oxygen
what happens to the ETC when there is a lack of oxygen?
the entire ETC is BLOCKED and no additional ATP is produced
what other substance inhibits normal activity of cytochromes?
poisons such as cyanide which binds to the iron in cytochromes and blocks ATP production
what sets the stage for chemiosmosis?
the ETC creates a proton gradient across the inner mitochondrial membrane
what is chemiosmosis?
the process by which ATP is formed as protons diffuse through transmembrane channels in ATP synthase
what occurs during the synthesis of ATP?
protons travel from the inter membrane space to the matrix through ATP synthase, ATP synthase rotates and catalyzes the phosphorylation of ADP to form ATP, chemiosmosis allows exergonic redox reactions to produce ATP
the oxidation of NADH in the ETC yields ?
3 ATP for each NADH
the oxidation of FADH2 yields?
2 ATP per molecules
what is the net yield of ATPs from NADH?
between 28 to 30
the role of amino acids and lipid?
amino acids and lipid are transformed into metabolic intermediates that enter glycolysis and the citric acid cycle
how are amino acids used during aerobic respiration?
the amino group is removed (deamination) and the carbon chain is used in aerobic respiration (urea is a waste product)
what can the remaining carbon chain from the deamination of amino acid be used for?
may be converted to pyruvate, OAA, or other metabolic intermediates
how are lipids used during aerobic respiration?
glycerol is converted to a compound that enters glycolysis and fatty acids are converted ti acetyl CoA, which enters the citric acid cycle
what is the final electron acceptor in anaerobic respiration?
inorganic nitrate or sulfate no O2
products of anaerobic respiration
CO2, reduced nitrate or sulfite, and ATP
which organisms used anaerobic respiration?
prokaryotes like waterlogged soil, stagnant ponds, and animal intestines
what happens to the electrons from glucose during anaerobic respiration?
electrons pass from NADH down an ETC coupled to ATP synthesis by chemiosmosis
what is fermentation?
an anaerobic pathway that does not involve an ETC; forms only 2 ATP per glucose, NADH molecules transfer H atoms to organic molecules (regenerating NAD+ needed for glycolysis)
what are alcohol fermentation and lactate fomentation inefficient?
NO ETC, highly inefficient because of the partially oxidized fuel; yeast (switch to alcohol fermentation when oxygen isn’t present), enzymes decarboxylate pyruvate forming acetaldehyde, and NADH produced during glycolysis transfers hydrogen atoms to acetaldehyde reducing it to ethyl alcohol
what kind of fermentation do certain fungi and bacteria perform?
lactate fermentation; NADH transfers H+ to pyruvate reducing it to lactate
what do vertebrate muscle cells produce when oxygen depleted during exercise?
lactate
