Chapter 13 : Energetics and Catabolism Flashcards
what is the yielding of energy from e- transfer between chemicals?
chemotrophy
what is the yielding of energy from light absorption?
phototrophy
what does NADH consist of?
ADP molecule attached to a nicotinamide ring
how does FADH2 compare to NADH?
it is weaker but similar in that they both donate 2e- to acceptor
what is the catalytic site of an enzyme?
part of the protein that binds with the substrate and catalyzes the reaction
what are carbohydrates broken down into in the catabolism process?
short chains(oligosaccharides), then to disaccharides, then monosaccharides
what are lipids broken down into during catabolism?
microbes catalyze lipids by hydrolysis to glycerol and fatty acids
what are peptides broken down into during catabolism?
broken down protein that are hydrolyzed to amino acids
what types of products are made in fermentation?
all e- are put back onto organic products
what types of products are made in respiration?
e- are transferred to inorganic acceptors, products are H2O and CO2
what are the three routes to pyruvate used by bacteria and archaea?
glycolysis, entner-doudoroff(ED) pathway, and the pentose-phosphate pathway(PPP)
what happens during glycolysis to G6P?
G6P isomerizes to F6P, which becomes 2 pyruvate molecules
what are the products of glycolysis?
2 pyruvate, 2 ATP, and 2 NADH
what happens to G6P in the PPP pathway?
it is oxidized to G6-phosphoglucanate, then decarbonxylated to a 5-carbon sugar(pentose) called ribulose 5-phosphate
what is the purpose of the sugars that the PPP pathway creates?
they are used as precursors to biosynthesis or are converted to pyruvate if necessary
what are the products of the ED pathway?
2 pyruvate, 1 ATP, 1 NADH, 1 NADPH
what are the products of the PPP pathway?
biosynthesis, 1 ATP, 2 NADPH
what happens to G6P in the ED pathway?
G6P is oxidized to G6-phosphoglucanate, making 2 pyruvate
what does it mean that ATP formation is substrate-level phosphorylation in lactic acid fermentation?
it only involves substrate ions, no proton pumping across membranes
how many ATP does lactic acid fermentation create?
2 ATP
how is pyruvate converted to lactic acid?
adding 2e-, so one glucose molecule becomes 2 lactic acid molcules(C3H6O3)
how many ATP are created in ethanolic fermentation?
2 ATP
what are the byproducts of ethanolic fermentation?
2 ethanol molecules and 2 CO2 molecules
how many ATP are created in heterolactic fermentation?
2 ATP
what are the byproducts of heterolactic fermentation?
one lactic acid, one ethanol, one CO2
what are the products of mixed-acid fermentation?
acetate, formate, succinate, ethanol, lactate, H2, CO2
in what process are the products of sugar breakdown catabolized into CO2 and H2O?
tricarboxylic acid cycle(TCA) cycle, a.k.a Krebs cycle
what molecules does the Krebs cycle generate that donates e- to ETS?
NADH and FADH2
where does the Krebs cycle occur in plant and animal cells?
in the mitochondria
what is the first step of the Krebs cycle, one that occurs before the loops starts?
pyruvate must be converted to acetyl CoA
what does the acetyl group condense with to form citrate?
oxaloacetate
what is citrate rearranged to become?
isocitrate
when isocitrate is decarboxylazed oxidatively, it transfers energy from 2H+ and 2e- to form NADH + H+. what does it become?
2-oxoglutarate
what does 2-oxoglutarate become once it is decarboxylzed, releasing CO2 and making NADH and H+?
succinyl-CoA
once succinyl-CoA releases CoA, it yields energy to phosphorylate ADP to ATP. what does it become?
succinate
why is FAD used instead of NAD in the succinyl-CoA step?
e- donation from succinyl-CoA does not yield enough energy to reduce NAD
what does fumarate incorporate in its double bond to form malate?
H2O, forming final NADH and H+
what does each acetate form in the Krebs cycle?
3 NADH, 1 FADH2, and 1 ATP
what is the process of e- transport and ATP generation known as?
oxidative phosphorylation
what happens to the Krebs cycle when glucose is scarce?
cells switch to the glyoxylate bypass which avoids losing carbons as CO2 to the atmosphere
