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


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

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?

in reaction 9, 2-phosphoglycerate loses one molecule of water to produce _______

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

• 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?

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

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
_____ 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

what is the true about the three control points of glycolysis
they are the first, last, and intermediate step