Amino Acids

Question 1

These amino acids cannot be synthesized in vivo at a fast enough rate, if at all, and must be acquired through dietary intake.

Answer 1

Essential Amino Acids

Question 2

What are the nine (9) essentially amino acids?

Answer 2

• Histidine
• Isoleucine
• Leucine
• Lysine
• Methionine
• Phenylalanine
• Threonine
• Tryptophan
• Valine

Question 3

This amino acid is essential, and is needed to help grow and repair body tissues, to maintain the myelin sheaths that protect nerve cells, and to serve as the precursor for several hormones and metabolites essential to renal, gastric, and immune function (e.g., histamine). It also plays an important role in the synthesis of red and white blood cells, in protecting the body from heavy metal toxicity, and serving as a source of carbon atoms in the synthesis of purines for DNA and RNA synthesis.

Answer 3

Histidine

Question 4

These are essential, branched-chain amino acids, collectively referred to as the branched-chain amino acid group.

Answer 4

Isoleucine, Leucine, and Valine

Question 5

This amino acid is essential, and is concentrated in muscle tissues and is essential for a number of functions such as wound healing, immune function, glucose homeostasis and hemoglobin formation.

Answer 5

Isoleucine

Question 6

This amino acid is essential, and is also important in the regulation of blood glucose and wound healing as well as prevention of muscle protein degradation subsequent to trauma.

Answer 6

Leucine

Question 7

This amino acid aids in determining the tertiary structure of proteins and promotes mental health and muscle coordination. And is an essential amino acid.

Answer 7

Valine

Question 8

This plays a role in the production of antibodies l and is required for maintaining healthy tissues. It also helps in the absorption and conservation of calcium and serves an important role in the formation of collagen, a component of cartilage and connective tissue. And is also essential.

Answer 8

Lysine

Question 9

This helps to initiate translation of messenger RNA, stabilizes protein structure, and is an important cellular antioxidant. It is an important source of sulfur, which is required for normal metabolism and growth. This also assists in the breakdown of fats, helps to detoxify lead and other heavy metals, helps diminish muscle weakness, and prevents brittle hair. This reacts with adenosine triphosphate (ATP) in the synthesis of many important substances, including epinephrine and choline, and is essential for proper absorption of selenium and zinc.

Answer 9

Methionine

Question 10

This metabolic precursor for tyrosine, which, in turn, is the precursor for the neurotransmitters dopamine, norepinephrine, and epinephrine, collectively referred to as catecholamines. Catecholamines perform several important roles in maintaining homeostasis through the autonomic nervous system such as promoting alertness and vitality, elevating mood, decreasing pain, and aiding in memory and learning. When deficient, downstream products such as tyrosine will also be decreased.

Answer 10

Phenylalanine

Question 11

This is an important component in the formation of collagen, elastin, and tooth enamel. It is also important in the production of neurotransmitters and overall health of the nervous system. Additionally, this helps maintain proper protein balance in the body, aids in liver function, and assists in metabolism of porphyrins and fats.

Answer 11

Threonine

Question 12

This is a metabolic precursor for serotonin and melatonin, which regulate appetite, mood, sleep, and pain. As such, this is a natural relaxant that helps alleviate insomnia by inducing sleep, soothes anxiety, and reduces depression. This is also essential for the production of niacin.

Answer 12

Trytophan

Question 13

Since additional dietary intake of these amino acids is unnecessary, they are classified as ____________.

Answer 13

Non-essential

Question 14

The human body can synthesize adequate amounts of …..?

Answer 14

• Alanine
• Asparagine
• Aspartic acid
• Glutamic acid
• Selenocysteine
• Serine

Question 15

This is a product of the breakdown of DNA, anserine, and carnosine. It is also formed as a result of glycolysis in muscle tissue and the conversion of pyruvate, a pivotal compound in carbohydrate metabolism, into α-ketoglutarate. This plays a major role in the transfer of nitrogen from peripheral tissues to the liver for processing and excretion and strengthens the immune system through production of antibodies. As a ketogenic amine, this also serves as a source of energy for the central nervous system, brain, and muscle tissues. It also helps in reducing the buildup of toxic substances released when muscle protein is broken down.

Answer 15

Alanine

Question 16

This is derived from aspartic acid and ATP through transamidation, in which an amide group is transferred from one compound to another. It is one of the principal and most abundant amino acids involved in the transport of nitrogen. It is required by the nervous system and plays an important role in the synthesis of ammonia. However, its primary function is in the conversion of one amino acid into another via amination or transamination. Amination is the process by which an amine group is introduced into an organic molecule, and transamination is the transfer of an amino acid to an α-ketoacid.

Answer 16

Asparagine

Question 17

This is synthesized from oxaloacetate through transamination in the citric acid cycle and the urea cycle. An important role of this is to serve as the precursor for several other amino acids, such as asparagine, arginine, lysine, methionine, threonine, and isoleucine, as well as several nucleotides. It also serves as a neurotransmitter and participates in the generation of glucose from non-carbohydrate substrates, a process known as gluconeogenesis.

Answer 17

Aspartate or Aspartic Acid

Question 18

This is produced from the transamination of amino acids such as alanine and aspartic acid. This serves as a neurotransmitter and has an important role in the metabolism of carbohydrates and fats as well as facilitating amino acid synthesis and degradation.

Answer 18

Glutamate or Glutamic Acid

Question 19

Unlike other amino acids present in proteins, is not coded for directly in the genetic code. Rather, it is encoded by a UGA codon, which is normally a stop codon; however, like the other amino acids used by cells, this has a specialized transfer RNA (tRNA). As its name implies, this is the selenium analogue of cysteine, in which a selenium atom replaces sulfur. This is present in several enzymes, such as formate dehydrogenases, glycine reductases, and some hydrogenases.

Answer 19

Selenocysteine

Question 20

This is synthesized from 3-phosphoglycerate, which is an intermediate in glycolysis. This is needed for the proper metabolism of lipids and fatty acids and plays an important role in the synthetic pathways for pyrimidines, purines, creatine, and porphyrins. It is highly concentrated in all cell membranes, serves as a component of the protective myelin sheaths surrounding nerve fibers, and aids in the production of antibodies.

Answer 20

Serine

Question 21

When adults can synthesize adequate amounts to meet the demands of the body.

Answer 21

Conditionally Essential Amino Acids

Question 22

These are classified as semi-essential, or conditionally essential, amino acids.

Answer 22

• Arginine
• Cysteine
• Glutamine
• Glycine
• Proline
• Tyrosine

Question 23

This is a complex amino acid often found at the catalytic site in proteins and enzymes due to its amine-containing side chain. This plays an important role in cell division, wound healing, stimulation of protein synthesis, immune function, and the release of hormones. Another important role of this is in the conversion of ammonia into urea.

Answer 23

Arginine

Question 24

This should not be confused with should not be confused with cystine, as they are two different amino acids. This is potentially toxic, so it is absorbed during digestion as cystine, which is more stable in the gastrointestinal tract and less toxic. Cystine is transported to cells, where it is reduced to two ________ molecules upon cell entry. This can also be synthesized in vivo from methionine through a series of enzymatic reactions. This is an important structural and functional component of many proteins. It is found in beta-keratin and is important in collagen formation. It also has antioxidant properties and involvement in metabolism of other molecules.

Answer 24

Cysteine

Question 25

This is synthesized from glutamic acid through the addition of an ammonia group and can donate the ammonia group to form urea, which is excreted by the kidneys. As such, this plays an integral role in regulation of ammonia, which is considered a toxic substance. Additionally, this has many other important functions, including renal maintenance of the acid–base balance, providing fuel for a healthy digestive tract, and acting as the basis of the building blocks for synthesis of RNA and DNA. This is also a source of cellular energy and aids in immune function.

Answer 25

Glutamine

Question 26

This is synthesized from the amino acid serine. It is essential for synthesis of nucleic acids, bile acids, proteins, peptides, purines, ATP, porphyrins, hemoglobin, glutathione, creatine, bile salts, glucose, glycogen, and other amino acids. This is also an inhibitory neurotransmitter in the central nervous system and a metal-complexing agent. Additionally, this limits muscle degeneration, improves glycogen storage, promotes healing, and is utilized by the liver in the detoxification of compounds.

Answer 26

Glycine

Question 27

This is produced from glutamic acid and other amino acids. It serves as the precursor for hydroxyproline, which is manufactured into collagen, tendons, ligaments, and cardiac tissue. This is also involved in wound healing, especially that of cartilage, and in the strengthening of joints, tendons, and cardiac tissue.

Answer 27

Proline

Question 28

This is synthesized from phenylalanine and serves as a precursor for adrenal and thyroid hormones. This stimulates metabolism and the nervous system, acts as a mood elevator, and aids in function of the adrenal, thyroid, and pituitary glands.

Answer 28

Tyrosine

Question 29

This is the process by which an amine group is introduced into an organic molecule.

Answer 29

Amination

Question 30

This is the transfer of an amino acid to an α-ketoacid. Or in which an amide group is transferred from one compound to another.

Answer 30

Transamidation