BCH 361 (LEFLER) MIDTERM 3, BCH 361 EXAM 1
UPDATED ACTUAL QUESTIONS AND CORRECT
ANSWERS
Question:
1. intermediary metabolism
Answer:
The entire set of cellular metabolic reactions, collectively
Question:
2. catabolism
Answer:
Metabolic pathways that break down molecules, releasing energy.
Question:
3. anabolism
Answer:
Metabolic pathways that construct molecules, requiring energy.
Question:
4. amphibolism
Answer:
Pathways that can be anabolic or catabolic, depending on what is required
Question:
5. standard free energy of hydrolysis
Answer:
amount of energy released when phosphorylated compound transfers
phosphoryl group to water under standard conditions
Question:
6. Reasons why ATP has a very high phosphoryl-transfer
potential
Answer:
1. Electrostatic repulsion (ATP had 4 negative charges at pH 7, which repulse one
another; this repulsion is reduced when bonds are broken) 2. Resonance
stabilization (orthophosphate, a product of ATP hydrolysis, is very stable due to
resonance) 3. Increase in entropy (2 molecules have higher entropy than one) 4.
Water binds to ADP and Pi, stabilizing them and making the reverse rxn
unfavorable
,Question:
7. NAD+ (nicotinamide adenine dinucleotide)
Answer:
electron carrier involved in glycolysis; higher affinity for electrons than carbon
fuels, but lower affinity than ultimate acceptors like O2; accepts a hydrogen ion
and 2e; derived from the vitamin niacin
Question:
8. FAD (flavin adenine dinucleotide)
Answer:
a compound that acts as a hydrogen acceptor in dehydrogenation reactions; can
accept 2 electrons and 2 protons; derived from the vitamin riboflavin
Question:
9. Coenzyme A (CoA-SH)
Answer:
carrier of acyl groups which has a high transfer potential
Question:
10. Metabolic process are regulated in 3 main ways
Answer:
amount of enzyme, their activity, their accessibility to substrate
Question:
11. energy charge
Answer:
Relationship between the concentrations of ATP, ADP, and AMP; value of 0
indicates all AMP, value of 1 indicates all ATP; energy charge is buffered, value
usually between 0.80 and 0.95
Question:
12. Phosphorylation potential
Answer:
A means of measuring the energy status of a cell that is derived by dividing the
concentration of ATP by the product of the concentrations of ADP and Pi.
Question:
13. Why is glucose a primary fuel source?
Answer:
1. can be formed from fromaldehyde under prebiotic conditions 2. it is the most
stable hexose due to low steric hinderance 3. low tendency to nonenzymatically
glycosylate proteins
, Question:
14. Kinases
Answer:
catalyze transfer of phosphoryl groups from ATP to an acceptor
Question:
15. Hexokinase
Answer:
catalyze transfer of phosphoryl groups from ATP to hexoses (6 Carbon sugars);
require Mg2+ or another divalent metal ion for activity; inhibited by t
Question:
16. The binding of glucose causes a conformational change
in hexokinase
Answer:
the closing of the cleft and resulting nonpolar environment around the glucose
molecule causes the donation of the terminal phosphoryl group of ATP
Question:
17. The isomerization of glucose-6-phosphate to fructose-6-
phosphate
Answer:
this is a conversion of an aldose to a ketose; , creating a symmetric 6 carbon unit
which is more easily cleaved into two 3-carbon units than the reactant
Question:
18. GAP
Answer:
a usable product formed from the cleavage of Fructose 1,6-Bisphosphate into
two, 3 carbon units
Question:
19. DHAP
Answer:
an unusable product formed from the cleavage of Fructose 1,6-Bisphosphate into
two, 3 carbon units; must be converted into GAP by triose phosphate isomerase
(TPI)
UPDATED ACTUAL QUESTIONS AND CORRECT
ANSWERS
Question:
1. intermediary metabolism
Answer:
The entire set of cellular metabolic reactions, collectively
Question:
2. catabolism
Answer:
Metabolic pathways that break down molecules, releasing energy.
Question:
3. anabolism
Answer:
Metabolic pathways that construct molecules, requiring energy.
Question:
4. amphibolism
Answer:
Pathways that can be anabolic or catabolic, depending on what is required
Question:
5. standard free energy of hydrolysis
Answer:
amount of energy released when phosphorylated compound transfers
phosphoryl group to water under standard conditions
Question:
6. Reasons why ATP has a very high phosphoryl-transfer
potential
Answer:
1. Electrostatic repulsion (ATP had 4 negative charges at pH 7, which repulse one
another; this repulsion is reduced when bonds are broken) 2. Resonance
stabilization (orthophosphate, a product of ATP hydrolysis, is very stable due to
resonance) 3. Increase in entropy (2 molecules have higher entropy than one) 4.
Water binds to ADP and Pi, stabilizing them and making the reverse rxn
unfavorable
,Question:
7. NAD+ (nicotinamide adenine dinucleotide)
Answer:
electron carrier involved in glycolysis; higher affinity for electrons than carbon
fuels, but lower affinity than ultimate acceptors like O2; accepts a hydrogen ion
and 2e; derived from the vitamin niacin
Question:
8. FAD (flavin adenine dinucleotide)
Answer:
a compound that acts as a hydrogen acceptor in dehydrogenation reactions; can
accept 2 electrons and 2 protons; derived from the vitamin riboflavin
Question:
9. Coenzyme A (CoA-SH)
Answer:
carrier of acyl groups which has a high transfer potential
Question:
10. Metabolic process are regulated in 3 main ways
Answer:
amount of enzyme, their activity, their accessibility to substrate
Question:
11. energy charge
Answer:
Relationship between the concentrations of ATP, ADP, and AMP; value of 0
indicates all AMP, value of 1 indicates all ATP; energy charge is buffered, value
usually between 0.80 and 0.95
Question:
12. Phosphorylation potential
Answer:
A means of measuring the energy status of a cell that is derived by dividing the
concentration of ATP by the product of the concentrations of ADP and Pi.
Question:
13. Why is glucose a primary fuel source?
Answer:
1. can be formed from fromaldehyde under prebiotic conditions 2. it is the most
stable hexose due to low steric hinderance 3. low tendency to nonenzymatically
glycosylate proteins
, Question:
14. Kinases
Answer:
catalyze transfer of phosphoryl groups from ATP to an acceptor
Question:
15. Hexokinase
Answer:
catalyze transfer of phosphoryl groups from ATP to hexoses (6 Carbon sugars);
require Mg2+ or another divalent metal ion for activity; inhibited by t
Question:
16. The binding of glucose causes a conformational change
in hexokinase
Answer:
the closing of the cleft and resulting nonpolar environment around the glucose
molecule causes the donation of the terminal phosphoryl group of ATP
Question:
17. The isomerization of glucose-6-phosphate to fructose-6-
phosphate
Answer:
this is a conversion of an aldose to a ketose; , creating a symmetric 6 carbon unit
which is more easily cleaved into two 3-carbon units than the reactant
Question:
18. GAP
Answer:
a usable product formed from the cleavage of Fructose 1,6-Bisphosphate into
two, 3 carbon units
Question:
19. DHAP
Answer:
an unusable product formed from the cleavage of Fructose 1,6-Bisphosphate into
two, 3 carbon units; must be converted into GAP by triose phosphate isomerase
(TPI)
