Biochem Exam 2 - Ch. 17
Discipline: Biology (and other Life Sciences)
Type of Paper: Question-Answer
Academic Level: Undergrad. (yrs 3-4)
Paper Format: APA
Pages: 1
Words: 275
Question
the old word for D-glucose dextrose
Optically active molecule that rotates light to the right Dextrorotatory (+)
old name for fructose levulose
Rotates polarized light to the left Levorotatory
is L-glucose commonly found in nature? no
the enantiomer of D-glucose L-glucose
the first stage of glucose catabolism glycolysis
the break down of sugar to get energy out of it glycolysis
a goal of glycolysis is to form high energy molecules, such as ___ and ____ as cellular energy sources ATP and NADH
a goal of glycolysis is the production of ________ for ___ and ____ production during the ______ ____ _____ pyruvate
ATP
NADH
ATP
NADH
citric acid cycles
a goal of glycolysis is to produce various 6 and 3 carbon intermediate compounds. what can these be used for? other cellular purposes
why does anaerobic glycolysis happen?
to make NAD+ in order to keep metabolizing glucose and pulling out ATP
this reaction is driven by the free energy of hydrolysis of ATP
reaction 1: glucose to glucose-6-phosphate
in reaction 1, the reaction of glucose to form glucose-6-phosphate, glucose-6-phosphate inhibits ________ hexokinase
hexokinase is inhibited by what process in reaction 1 of glycolysis?
feed back inhibition
the second step (reaction 2) in glycolysis is _______
the isomerization of glucose-6-phosphate to fructose-6-phosphate
T/F: Reaction 2 in glycolysis is energetically close to equilibrium true
what is the enzyme involved in reaction 2 of glycolysis that isomerizes G6P to F6P glucosephosphate isomerase
in reaction 3 of glycolysis, what enzyme converts Fructose-6-phosphate to fructose-1,6-bisphosphate phosphofructokinase
what enzyme in glycolysis reaction 4, splits fructose-1,6-bisphosphate into two 3-carbon fragments? Aldolase
reaction 4 in glycolysis is an ________ reaction, therefore it has cost us ______
endergonic, energy
in
reaction 5 of glycolysis, what enzyme facilitates the isomerization of
dihydroxyacetone phosphate to D-glyceraldehyde-3-phosphate?
triosephosphate isomerase
how many molecules of glyceraldehyde-3-phosphate do we end up with in reaction 5 from the one original glucose? 2
how many ATPs were lost or gained from reaction 1-5? 2 lost
reaction 6 involves what 2 processes? oxidation and phosphorylation
in the oxidation step of reaction 6, glyceraldehyde-3-phosphate gets oxidized to _________ 3-phospoglycerate
in the oxidation step of reaction 6, how does glyceraldehyde-3-phosphate get oxidized to 3-phosphoglycerate?
the -CHO group is oxidized to a carboxyl group (COOH)
in the oxidation step of reaction 6, NAD+ gets reduced to ____ NADH
what is needed for reaction 6 to happen? NAD+
In the phosphorylation step of reaction 6, 3-phosphoglycerate gets phosphorylated to ____________ 1,3-bisphosphoglycerate
in reaction 7, how does 1,3-bisphosphoglycerate participate in substrate level phosphorylation? by transferring a phosphate group to ADP
in reaction 7, what enzyme catalyzes the conversion of 1,3-bisphosphoglycerate to 3 phosphoglycerate? phosphoglycerate kinase
the sum of the endergonic phosphorylation of ADP and the exergonic hydrolysis of the phosphate off 1,3-bisphosphoglycerate reaction 7
reaction 8 involves the isomerization of ___________ to ____________
3-phosphoglycerate to 2-phosphoglycerate
in reaction 8, the isomerization of 3-phosphoglycerate to 2-phoshoglycerate is catalyzed by what enzyme?
phosphoglyceromutase
in reaction 9, 2-phosphoglycerate loses one molecule of water to produce _______
phosphenolpyruvate
in reaction 9, the formation of PEP is catalyzed by _________ and requires a ____ cofactor. enolase, Mg2+
in reaction 10, phosphoenolpyruvate is converted to what? pyruvate
in reaction 10, phosphoenolpyruvate conversion to pyruvate is catalyzed by what enzyme? pyruvate kinase
reaction 10 is the sum of a _________ _________exergonic hydrolysis
how many ATPs are released in reaction 10? 2
Three
reactions exhibit particularly large decreases in free energy
(exergonic) the enzymes that catalyze these reactions are sites of
allosteric control of glycolysis hexokinase
- phosphofructokinase
- pyruvate kinase
what are the 3 fates of pyruvate in glycolysis -reduction to lactate
-reduction to ethanol
-oxidation and decarboxylation to acetyl-CoA
-reduction to ethanol
-oxidation and decarboxylation to acetyl-CoA
• Glycolysis needs a continuing supply of NAD +
– if no oxygen is present to reoxidize NADH to NAD + , then another
way must be found to reoxidize it – Steps one and two (above) fulfill
this need
pyruvate kinase is activated by fructose-1,6-bisphosphate via
feedforward activation
in vertebrates under anaerobic conditions, the most important pathway for the regeneration of NAD+ is _______________________
reduction of pyruvate to lactate
fermentation
of _______ allows glycolysis to continue while it also increases the
concentration of _________ and H+ in muscle tissue. lactate, lactate
what happens to muscle tissue when blood lactate reaches about 0.4 mg/100 mL? becomes almost completely exhausted
in anaerobic alcohol fermentation in yeast, what is pyruvate converted into?
ethanol
the
two step pathway of converting pyruvate to ethanol via anaerobic
alcohol fermentation allows yeasts and other microbes to do what?
regenerate NAD+
what is the 2 step pathway of anaerobic alcohol fermentation?
1. decarboxylation of pyruvate to acetaldehyde
2. reduction acetaldehyde to ethanol
2. reduction acetaldehyde to ethanol
glycolysis is the
conversion of 1 mole of glucose to 2 moles of pyruvate
after glycolysis, pyruvate can undergo....
both ethanol production and lactic acid production in mammals
Before glucose is split into two 3-carbon sugars, it is converted to
fructose-1,6-bisphosphate
_____ is cleaved by ____ to produce two 3-carbon sugars
fructose-1,6-bisphosphate; aldolase
in the second half of glycolysis..... ATP forming reactions take place
Which 2 enzymes of glycolysis form ATP from ADP and Pi?
Phosphoglycerate kinase and pyruvate
an important step in anaerobic lactic acid production is to.....
produce NAD+ to be used again in glycolysis
Phosphofructokinase converts _______ to _________.
fructose-6-phosphate; fructose-1,6-bisphosphate
Which of the following steps is one of the three control point in glycolysis
1) phosphoenolpyruvate to pyruvate 3-phosphoglycerate to 2-phosphoglycerate 3) dihydroxyacetone phosphate to glyceraldephyde-3-phosphate 4) glucose-6-phosphate to fructose-6-phosphate
1) phosphoenolpyruvate to pyruvate 3-phosphoglycerate to 2-phosphoglycerate 3) dihydroxyacetone phosphate to glyceraldephyde-3-phosphate 4) glucose-6-phosphate to fructose-6-phosphate
1) phosphoenolpyruvate to pyruvate
what is the true about the three control points of glycolysis
they are the first, last, and intermediate step