The controlled, stepwise oxidation of sugar in cells captures useful ____, unlike the simple _____ of the same fuel molecule.
energy
burning
the direct ______ of sugar in nonliving systems generates more energy than can be stored by any ______ molecule. This energy is thus released as ____.
burning
carrier
heat
in a cell, enzymes ______ the breakdown of sugars via a series of small steps, in which portion of the _____ _____ released is captured by the formation of activated carriers-most often ATP and ____. Each step is catalyzed by an enzyme that lowers the ___
catalyze
free energy
NADH
activation energy
collision
Which stage and which process shown in Figure 13-3 generates the most ATP
stage 3, oxidative phosphorylation
What are the locations of glycolysis,citric acid cycle, oxidative phosphorylation, and the conversion of fatty acid to acetyl CoA, in a cell?
Glycolysis-______ (stage _)
Citric acid cycle-______ _____ (stage _)
Oxidative phosphorylation-________ _____ (st
cytosol (2)
mitochondrial matrix (3)
mitochondrial matrix (3)
cytosol
outer
inner
matrix
2
The breakdown of food molecules occurs in 3 steps
Stage one mostly occurs outside cells in the ____ and ___-although intracellular ______ can also digest large organic molecules.
Stage 2 occurs mainly in the ______, except for the final step of conversion
mouth and gut
lysosomes
cytosol
pyruvate
matrix
oxidative phosphorylation
The NADH generated in stage 2-during _______ and the conversion of pyruvate to acetyl CoA- adds to the NADH produced by the citric acid cycle to drive the production of ____ by oxidative phosphorylation.
glycolysis
ATP
What are the net products of the complete oxidation of food?
ATP+NADH+CO2+H2O
Glycolysis splits a molecule of glucose to form _ molecules of pyruvate.
The process requires an input of energy, in the form of ATP, at the start. This energy investment is later recouped by the production of _ NADHs and _ ATPs.
2
2 and 4
Products of fermentation in an active muscle cells and in yeast cell ______ is broken down in the absence of ______ by fermentation
pyruvate
oxygen
when inadequate oxygen is present, for ex., in a muscle cell undergoing vigorous contraction, the pyruvate produced by glycolysis is converted to ______ in the cytosol. This reaction restores the _____ consumed in step 6 of _______ but the whole pathway y
lactate
NAD+
glycolysis
in microorganisms that can grow __________, pyruvate is converted into _____ _____ and _____l. Again, this pathway regenerates NAD+ from NADH, as required to enable glycolysis to continue. Note that in both cases, for each molecule of glucose that enters
anaerobically
carbon dioxide and ethanol
2
What is the net result of one turn of the citric acid cycle?
_ NADH
_GTP
_FADH2
releases _ molecules of CO2
3
1
1
2
citric acid cycle begins with the reaction of ____ ____(derived from pyruvate) with oxaloacetate(4C) to produce _____(citric acid
acetyl CoA(2C)
citrate(6C)
Pyruvate is converted into acetyl CoA and CO2 by the pyruvate _________ complex in
the mitochondrial matrix
dehydrogenase
the pyruvate dehydrogenase complex, which contains multiple copies of 3 different enzymes-
(1)______ _______, (2)dihydrolipoyl ________, and
(3)dihydrolipoyl _______ - converts _____ to acetyl CoA; NADH and CO2 are also produced in this reaction.
pyruvated dehydrogenase
transacetylase
dehydrogenase
pyruvate
the pyruvate dehydrogenase complex is larger than a _____
ribosome
Glycolysis and the citric acid cycle provide the _______ needed for cells to synthesize
many important organic molecules
precursors
the amino acids, ________, lipids, ______, and other molecules in turn serve as the precursors for many of the cells macromolecules
nucleotides
sugars
glycolysis:Activated by ______ of ATP hydrolysis- including ADP,___, and inorganic phosphate-and it is inhibited by ___
byproducts
AMP
ATP
The enzyme __________ catalyzes the phosphorylation of fructose 6-phosphate to form fructose 1,6-_______ in step 3 of glycolysis. This reaction is so energetically favorable that the enzyme will not work in reverse. To produce fructose 6-phosphate in gluc
phosphofructokinase
bisphosphate
bisphosphatase
What are the activators and inhibitors of fructose 1,6-bisphosphatase involved in
gluconeogenesis?
Regulated by the same molecules but in the _____ ______. Activated when phosphofructokinase is turned ___
opposite direction
off
Animal cells store glucose in the form of ______ to provide energy in times of need
glycogen
glycogen granules in the _____ of a liver cell; each granule contains both glycogen and the enzymes required for glycogen synthesis and _______.
the enzyme glycogen _________ breaks down glycogen when cells need more glucose
cytoplasm
breakdown
phosphorylase
Fats are stored in the form of fat droplets in animal cells
The fat droplets are in the _______ of developing ______
cytoplasm
adipocytes
Plant cells store both starch and fats in their _______
chloroplasts