CHEM 301 Biochem Final Exam
Questions & Answers (Grade A+)
For metabolism in multicellular organisms to proceed efficiently, it
is important that the final products be gases, water, or both. Why? -
correct answer ✅To maintain metabolism in a steady state, there
must be no possibility of a build-up of final products. The easiest
disposal products are the multicellular organism's universal solvent,
gases, or both.
Compare the tendency of NADH to donate electrons and the
tendency of oxygen to accept them. If NADH and oxygen are mixed,
will the electrons stay with NADH or go to oxygen? -
correct answer ✅If NADH and oxygen are mixed, electrons will be
transferred from NADH to oxygen with the release of considerable
energy:
NADH + ADH + ½ O2 + H+ ↔ NAD+ + H2O εo′ = 1.13 V
What structural feature do the "high-energy" compounds ATP,
FADH2, and NADH share with acetyl-CoA? -
correct answer ✅The "high-energy" compounds share an ADP unit
or, in the case of acetyl-CoA, a closely related derivative.
What is an anabolic process? -
correct answer ✅a biochemical reaction that synthesizes larger
molecules from smaller molecules. They are reductive in nature.
,CHEM 301 Biochem Final Exam
Questions & Answers (Grade A+)
What is a catabolic process? -
correct answer ✅An oxidative process. A larger molecule is broken
down into smaller ones. They are the primary energy source for
heterotrophic organisms.
Reductive processes require... -
correct answer ✅electron sources such as NADPH, NADH, or
FADH2
Oxidative processes require... -
correct answer ✅electron carriers such as NAD+, NADP+, or FAD
Glycolysis is controlled by... -
correct answer ✅-how fast glucose flows into the cell
-how quickly pyruvate can be used up
-whether any of the ten "products" are diverted to other reactions
-the concentration of catalysts that control the ten reactions
-feedback loops in which products of the ten reactions regulate
preceding reactions
,CHEM 301 Biochem Final Exam
Questions & Answers (Grade A+)
3 categories of organic reactions that occur in vivo -
correct answer ✅-oxidative and reductive
-elimination, isomerization, and rearrangement reactions
-group transfer reactions
What makes a high energy compound? -
correct answer ✅The magnitude of ΔGo′ of hydrolysis and the
redox potential
The more negative ΔGo′... -
correct answer ✅The greater the energy release and therefore the
greater energy in the original bond
The energy released comes from 3 sources: -
correct answer ✅-resonance: more structures for products
-electrostatic repulsion: lower in products than reactants
-entropy: greater for products
The greater the gain in resonance stabilization... -
correct answer ✅the greater relief from electrostatic repulsion
and the greater gain in entropy produced by a chemical change, the
greater the energy released.
, CHEM 301 Biochem Final Exam
Questions & Answers (Grade A+)
What does εo′ represent? -
correct answer ✅The redox potential of compounds in a standard
state.
Glycolysis is inhibited by iodoacetic acid through inactivation of the
enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). As a
result, there is an accumulation of fructose-1,6-biphosphate. Why is
this product more prevalent than glyceraldehyde-3-phosphate and
dihydroxyacetone phosphate, the products that form immediately
preceding GAPDH? -
correct answer ✅The reaction that converts fructose
1,6-bisphosphate to glyceraldehyde-3-phosphate and
dihydroxyacetone phosphate is near equilibrium in vivo (i.e., ΔG
near zero), while the preceding reaction producing fructose
1,6-bisphosphate is not. Therefore it is F1,6BP that will accumulate,
not glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.
The "Pasteur effect" is the dramatic decrease in glucose
consumption when oxygen is introduced to an anaerobic
fermentation broth. Why do the yeast cells use less glucose after
oxygen is introduced? How much less glucose do they use after
oxygen is introduced? -
correct answer ✅The introduction of oxygen allows yeast to
Questions & Answers (Grade A+)
For metabolism in multicellular organisms to proceed efficiently, it
is important that the final products be gases, water, or both. Why? -
correct answer ✅To maintain metabolism in a steady state, there
must be no possibility of a build-up of final products. The easiest
disposal products are the multicellular organism's universal solvent,
gases, or both.
Compare the tendency of NADH to donate electrons and the
tendency of oxygen to accept them. If NADH and oxygen are mixed,
will the electrons stay with NADH or go to oxygen? -
correct answer ✅If NADH and oxygen are mixed, electrons will be
transferred from NADH to oxygen with the release of considerable
energy:
NADH + ADH + ½ O2 + H+ ↔ NAD+ + H2O εo′ = 1.13 V
What structural feature do the "high-energy" compounds ATP,
FADH2, and NADH share with acetyl-CoA? -
correct answer ✅The "high-energy" compounds share an ADP unit
or, in the case of acetyl-CoA, a closely related derivative.
What is an anabolic process? -
correct answer ✅a biochemical reaction that synthesizes larger
molecules from smaller molecules. They are reductive in nature.
,CHEM 301 Biochem Final Exam
Questions & Answers (Grade A+)
What is a catabolic process? -
correct answer ✅An oxidative process. A larger molecule is broken
down into smaller ones. They are the primary energy source for
heterotrophic organisms.
Reductive processes require... -
correct answer ✅electron sources such as NADPH, NADH, or
FADH2
Oxidative processes require... -
correct answer ✅electron carriers such as NAD+, NADP+, or FAD
Glycolysis is controlled by... -
correct answer ✅-how fast glucose flows into the cell
-how quickly pyruvate can be used up
-whether any of the ten "products" are diverted to other reactions
-the concentration of catalysts that control the ten reactions
-feedback loops in which products of the ten reactions regulate
preceding reactions
,CHEM 301 Biochem Final Exam
Questions & Answers (Grade A+)
3 categories of organic reactions that occur in vivo -
correct answer ✅-oxidative and reductive
-elimination, isomerization, and rearrangement reactions
-group transfer reactions
What makes a high energy compound? -
correct answer ✅The magnitude of ΔGo′ of hydrolysis and the
redox potential
The more negative ΔGo′... -
correct answer ✅The greater the energy release and therefore the
greater energy in the original bond
The energy released comes from 3 sources: -
correct answer ✅-resonance: more structures for products
-electrostatic repulsion: lower in products than reactants
-entropy: greater for products
The greater the gain in resonance stabilization... -
correct answer ✅the greater relief from electrostatic repulsion
and the greater gain in entropy produced by a chemical change, the
greater the energy released.
, CHEM 301 Biochem Final Exam
Questions & Answers (Grade A+)
What does εo′ represent? -
correct answer ✅The redox potential of compounds in a standard
state.
Glycolysis is inhibited by iodoacetic acid through inactivation of the
enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). As a
result, there is an accumulation of fructose-1,6-biphosphate. Why is
this product more prevalent than glyceraldehyde-3-phosphate and
dihydroxyacetone phosphate, the products that form immediately
preceding GAPDH? -
correct answer ✅The reaction that converts fructose
1,6-bisphosphate to glyceraldehyde-3-phosphate and
dihydroxyacetone phosphate is near equilibrium in vivo (i.e., ΔG
near zero), while the preceding reaction producing fructose
1,6-bisphosphate is not. Therefore it is F1,6BP that will accumulate,
not glyceraldehyde-3-phosphate and dihydroxyacetone phosphate.
The "Pasteur effect" is the dramatic decrease in glucose
consumption when oxygen is introduced to an anaerobic
fermentation broth. Why do the yeast cells use less glucose after
oxygen is introduced? How much less glucose do they use after
oxygen is introduced? -
correct answer ✅The introduction of oxygen allows yeast to
