Deck 31: Amino Acids Synthesis

Question 1

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
The process of converting N2 to NH3 is called _______________.

Answer 1

d

Question 2

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
Isozymes, or multiple enzymes with the same identical catalytic properties but with different regulation, are an example of _______________.

Answer 2

j

Question 3

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
The final product pathway which inhibits an enzyme that catalyzes its production typically takes place at the _______________ step.

Answer 3

h

Question 4

Glutamine synthetase adds NH3 to __________________ to make glutamine.

Question 5

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
_______________ is the original nitrogen source for the nitrogen found in amino acids.

Question 6

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
_______________ is the site of nitrogen fixation by nitrogenase enzymes.

Question 7

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
A versatile carrier of one-carbon units is _______________.

Question 8

The enzyme __________________ is regulated by cumulative feedback inhibition.

Question 9

The α-amino group found in most amino acids comes from __________________ through a transamination reaction.

Question 10

The binding of serine to 3-phosphoglycerate dehydrogenase induces a __________________ in Vmax.

Question 11

Glutamate is the precursor for the amino acids glutamine, proline, and __________________.

Question 12

Only a few prokaryotes, such as __________________, are able convert N2 to ammonia.

Question 13

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
Methylcobalamine is derived from vitamin _______________.

Question 14

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
Glutamine synthesis inhibited by _______________ feedback inhibition.

Question 15

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
_______________ is a cofactor for transamination reactions.

Question 16

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) atmospheric nitrogen (N2)
b) 3-phosphoglycerate
c) cumulative
d) nitrogen fixation
e) B12
f) histidine
g) tetrahydrofolate
h) committed
i) pyridoxal phosphate
j) enzyme multiplicity
k) MoFe cofactor
l) ammonia (NH3)
The precursor for serine, cysteine, and glycine amino acid biosynthesis is _______________.

Question 17

__________________ ATP molecules are hydrolyzed for each N2 reduced.

Question 18

Metabolic pathways that have alternate products are often regulated by __________________and ____________.

Question 19

Methyl, methylene, and __________________ units can be carried by tetrahydrofolate.

Question 20

Homocysteine is an intermediate in the synthesis of cysteine and __________________.

Question 21

Organisms capable of carrying out reduction of atmospheric nitrogen include:

A) some bacteria and archaea.
B) higher eukaryotic organisms, such as mammals.
C) all plants.
D) All of the above.
E) None of the above.

Question 22

Describe the process and proteins involved in nitrogen fixation.

Question 23

The carbon skeletons for amino acids are intermediates found in:

A) glycolysis.
B) the citric acid cycle.
C) the pentose phosphate pathway.
D) All of the above.
E) None of the above.

Question 24

What is significant about many of the intermediates in amino acid biosynthesis?

Question 25

This amino acid, in high levels, is correlated with the damage of cells lining the blood vessels.

A) serine
B) cysteine
C) S-adenosylmethionine
D) citrulline
E) homocysteine

Question 26

Amino acid synthesis is generally regulated by:

A) turnover.
B) diet.
C) feedback and allosteric enzyme regulation.
D) A and B.
E) A, B, and C.

Question 27

Essential amino acids differ from nonessential amino acids in that:

A) nonessential amino acids are synthesized in simple reactions compared to many for most essential amino acids.
B) essential amino acids are generally synthesized directly from citric acid cycle intermediates, but nonessential amino acids are not.
C) microorganisms and animals cannot synthesize essential amino acids but plants can.
D) animals cannot synthesize essential amino acids because they have lost the ability to carry out transamination reactions.
E) None of the above.

Question 28

What determines the range of one-carbon units carried by tetrahydrofolate?

Question 29

Essential amino acids are synthesized by:

A) microorganisms.
B) humans.
C) plants.
D) A and B.
E) A and C.

Question 30

Which gaseous plant hormone is involved in triggering ripening?

A) melanin
B) epinephrine
C) ethylene
D) A and B
E) A and C

Question 31

Erythrose 4-phosphate is a precursor to the amino acids:

A) tryptophan, tyrosine, and phenylalanine.
B) tryptophan and phenylalanine.
C) tyrosine and phenylalanine.
D) tryptophan, tyrosine, phenylalanine, and serine.
E) None of the above.

Question 32

The electrons for the reduction of molecular nitrogen are donated by:

A) proteins.
B) NADPH.
C) ferredoxin.
D) None of the above.
E) All of the above.

Question 33

Through what process might feedback inhibition processes have evolved?

A) duplication of genes encoding catalytic domains
B) evolution of homologous subunits in the enzyme catalyzing the committed step
C) linking specific regulator domains to catalytic domains
D) linking of multiple regulatory domains
E) All of the above.

Question 34

An example of a reaction controlled by enzyme multiplicity is:

A) phosphorylation of asparagine by aspartokinases.
B) phosphorylation of aspartate by aspartokinases.
C) phosphorylation of glutamine by glutamine synthetase.
D) All of the above.
E) None of the above.

Question 35

The activated methyl cycle involves the production and use of:

A) glutamine.
B) glycine.
C) heterocysteine.
D) homocysteine.
E) methanol.

Question 36

Which amino acid is added to indole to form tryptophan?

A) glutamine
B) serine
C) tyrosine
D) All of the above.
E) None of the above.

Question 37

The rates of synthesis of amino acid metabolic pathways often depends on the:

A) committed step.
B) allosteric regulation.
C) feedback inhibition.
D) All of the above.
E) None of the above.

Question 38

S-adenosylmethionine carries which groups?

A) methyl
B) CO2
C) ammonia
D) None of the above.
E) All of the above.

Question 39

What is the MoFecofactor?

Question 40

What is a major difference between the amino acid biosynthetic capacity of prokaryotic organisms and humans?

Question 41

Draw homocysteine.

Question 42

Describe the effect of cumulative inhibition.

Question 43

Describe the regulation of the enzyme threonine deaminase.

Question 44

What is the advantage of the cumulative enzymatic regulation of glutamine synthetase activity?

Question 45

What would be the result of a pathway such as that shown in Figure 31.12 if only one enzyme catalyzed the first reaction? What if there were inhibition only by X and not by Y?

Question 46

What is enzyme multiplicity?

Question 47

What do S-adenosylmethionine and fruit ripening have in common?