Question 1

Glutamine,arginine,and proline:

Accepted Answer

Glutamine, arginine, and proline can all be derived from the citric acid cycle intermediate α-ketoglutarate, which can be transaminated to form glutamate. Glutamate can then be used to synthesize glutamine, or it can be further modified to form arginine or proline.

Question 2

If glucose labeled with ¹⁴C at C-1 were the starting material for amino acid biosynthesis,the product(s)that would be readily formed is (are):

Accepted Answer

C

Question 3

Erythrose 4-phosphate is a precursor of:

Accepted Answer

Erythrose 4-phosphate is a precursor for aromatic amino acids such as phenylalanine through the shikimate pathway.

Question 4

Homoserine is:

Accepted Answer

The answer of Homoserine is:
...

Question 5

Which of the following is not true about the anammox reaction?

Accepted Answer

Anammox is not performed by symbiotic bacteria of leguminous plants, but rather by specific bacterial species such as Brocadia, Kuenenia, and Scalindua.

Question 6

The nitrogen atom in the indole ring of tryptophan is derived from which amino acid?

Accepted Answer

The nitrogen atom in the indole ring of tryptophan is derived from the amino acid glutamine, which donates its amide nitrogen to form the heterocyclic indole ring.

Question 7

The nitrogen atom in the side chain of lysine is derived from which amino acid?

Accepted Answer

The answer of The nitrogen atom in the side chain...

Question 8

An important intermediate in the biosynthetic pathway to aromatic amino acids is:

Accepted Answer

Shikimate is an important intermediate in the biosynthetic pathway to aromatic amino acids, including phenylalanine, tyrosine, and tryptophan. It is produced from the condensation of erythrose-4-phosphate and phosphoenolpyruvate, and serves as a precursor for a range of important plant secondary metabolites such as phenolic acids, tannins, and lignin.

Question 9

Which of the following statements about the fixation of atmospheric nitrogen (N₂)into NH₃ by living cells is false?

Accepted Answer

The statement that "It requires one ATP per mol of N2 fixed" is false. In fact, the process of nitrogen fixation requires quite a bit of energy, and typically requires the hydrolysis of 16-20 ATP molecules per mole of N2 fixed. The ATP is used to activate the enzyme nitrogenase, which is responsible for actually reducing N2 to NH3.

Question 10

The amino acid __________ and is an intermediate in the biosynthesis of _________.

Accepted Answer

The answer of The amino acid __________ and is an...

Question 11

If a cell were unable to synthesize or obtain tetrahydrofolic acid (H₄ folate),it would probably be deficient in the biosynthesis of:

Accepted Answer

Tetrahydrofolic acid is required for the biosynthesis of methionine through the conversion of homocysteine to methionine. Therefore, a deficiency in tetrahydrofolic acid would likely result in a deficiency in the biosynthesis of methionine.

Question 12

Glutamine synthetase converts _____ to _____ whereas glutamate synthase converts ____ to _____.

Accepted Answer

Glutamine synthetase catalyzes the conversion of glutamate to glutamine by incorporating an ammonia molecule. Glutamate synthase, on the other hand, converts α-ketoglutarate and glutamine (not directly mentioned in the options but implied through the process) to two molecules of glutamate, effectively recycling glutamine back into glutamate while incorporating an additional nitrogen atom.

Question 13

Which of the following enzymes is not involved in the assimilation of inorganic nitrogen into an organic molecule?

Accepted Answer

The answer of Which of the following enzymes is not...

Question 14

An amino acid that does not derive its carbon skeleton,at least in part,from $\alpha$-ketoglutarate is:

Accepted Answer

Threonine does not derive its carbon skeleton from α-ketoglutarate. Instead, it is synthesized from aspartate. Arginine, glutamate, glutamine, and proline are all derived from α-ketoglutarate.

Question 15

In which group are all the amino acids closely interrelated metabolically?

Accepted Answer

Ornithine, proline, arginine, and glutamate are all closely interrelated metabolically in the urea cycle, the pathway that converts toxic ammonia into urea for excretion by the kidneys. These amino acids are involved in various steps of the cycle, and their metabolism is tightly regulated to maintain proper nitrogen balance in the body. The other groups of amino acids listed do not share such a close metabolic relationship.

Question 16

Nonessential amino acids:

Accepted Answer

Nonessential amino acids can be synthesized by the human body as well as by bacteria.

Question 17

The enzymatic machinery to fix atmospheric N₂ into NH₄⁺ is:

Accepted Answer

The conversion of N₂ to NH₄⁺ is carried out by the enzyme nitrogenase, which is composed of two key proteins (Fe protein and MoFe protein), each containing iron. Therefore, choice B is the correct answer. The other choices are incorrect: A is false because the enzymatic machinery does not produce ATP; C is false because the enzymatic machinery is sensitive to oxygen; D is false because nitrogenase is found in a variety of prokaryotic and some eukaryotic cells; and E is false because the supply of electrons is essential for the enzymatic reaction to occur.

Question 18

Which of the following is not true about glutamine amidotransferases?

Accepted Answer

Glutamine amidotransferases do not require ATP to activate glutamine; they catalyze the transfer of an amide group from glutamine to an acceptor molecule without the need for ATP.

Question 19

Which of the following enzymes is not involved in the assimilation of inorganic nitrogen into an organic molecule?

Accepted Answer

Nitrile reductase is not involved in the assimilation of inorganic nitrogen into an organic molecule. Dinitrogenase reductase, nitrate reductase, nitrite reductase, and dinitrogenase are all enzymes involved in the process of nitrogen assimilation.

Question 20

An amino acid that does not derive its carbon skeleton,at least in part,from oxaloacetate is:

Accepted Answer

Proline does not derive its carbon skeleton from oxaloacetate. Instead, it is synthesized from glutamate.

Quiz 22: Biosynthesis of Amino Acids, nucleotides, and Related Molecules

Glutamine,arginine,and proline:

If glucose labeled with ¹⁴C at C-1 were the starting material for amino acid biosynthesis,the product(s) that would be readily formed is (are) :

Erythrose 4-phosphate is a precursor of:

Homoserine is:

Which of the following is not true about the anammox reaction?

The nitrogen atom in the indole ring of tryptophan is derived from which amino acid?

The nitrogen atom in the side chain of lysine is derived from which amino acid?

An important intermediate in the biosynthetic pathway to aromatic amino acids is:

Which of the following statements about the fixation of atmospheric nitrogen (N₂) into NH₃ by living cells is false?

The amino acid __ and is an intermediate in the biosynthesis of _.

If a cell were unable to synthesize or obtain tetrahydrofolic acid (H₄ folate) ,it would probably be deficient in the biosynthesis of:

Glutamine synthetase converts ___ to _ whereas glutamate synthase converts to ___.

Which of the following enzymes is not involved in the assimilation of inorganic nitrogen into an organic molecule?

An amino acid that does not derive its carbon skeleton,at least in part,from $\alpha$ -ketoglutarate is:

In which group are all the amino acids closely interrelated metabolically?

Nonessential amino acids:

The enzymatic machinery to fix atmospheric N₂ into NH₄⁺ is:

Which of the following is not true about glutamine amidotransferases?

Which of the following enzymes is not involved in the assimilation of inorganic nitrogen into an organic molecule?

An amino acid that does not derive its carbon skeleton,at least in part,from oxaloacetate is:

Quiz 22: Biosynthesis of Amino Acids, nucleotides, and Related Molecules

Glutamine,arginine,and proline:

If glucose labeled with 14C at C-1 were the starting material for amino acid biosynthesis,the product(s) that would be readily formed is (are) :

Erythrose 4-phosphate is a precursor of:

Homoserine is:

Which of the following is not true about the anammox reaction?

The nitrogen atom in the indole ring of tryptophan is derived from which amino acid?

The nitrogen atom in the side chain of lysine is derived from which amino acid?

An important intermediate in the biosynthetic pathway to aromatic amino acids is:

Which of the following statements about the fixation of atmospheric nitrogen (N2) into NH3 by living cells is false?

The amino acid __________ and is an intermediate in the biosynthesis of _________.

If a cell were unable to synthesize or obtain tetrahydrofolic acid (H4 folate) ,it would probably be deficient in the biosynthesis of:

Glutamine synthetase converts _____ to _____ whereas glutamate synthase converts ____ to _____.

Which of the following enzymes is not involved in the assimilation of inorganic nitrogen into an organic molecule?

An amino acid that does not derive its carbon skeleton,at least in part,from α\alphaα -ketoglutarate is:

In which group are all the amino acids closely interrelated metabolically?

Nonessential amino acids:

The enzymatic machinery to fix atmospheric N2 into NH4+ is:

Which of the following is not true about glutamine amidotransferases?

Which of the following enzymes is not involved in the assimilation of inorganic nitrogen into an organic molecule?

An amino acid that does not derive its carbon skeleton,at least in part,from oxaloacetate is:

If glucose labeled with ¹⁴C at C-1 were the starting material for amino acid biosynthesis,the product(s) that would be readily formed is (are) :

Which of the following statements about the fixation of atmospheric nitrogen (N₂) into NH₃ by living cells is false?

The amino acid __ and is an intermediate in the biosynthesis of _.

If a cell were unable to synthesize or obtain tetrahydrofolic acid (H₄ folate) ,it would probably be deficient in the biosynthesis of:

Glutamine synthetase converts ___ to _ whereas glutamate synthase converts to ___.

An amino acid that does not derive its carbon skeleton,at least in part,from $\alpha$ -ketoglutarate is:

The enzymatic machinery to fix atmospheric N₂ into NH₄⁺ is: