Biology: Nine Essential Amino Acids Practice
Identify, classify, and apply the role of essential amino acids in human nutrition
Biology: Nine Essential Amino Acids Practice
Identify, classify, and apply the role of essential amino acids in human nutrition
Biology - Grade 9-12
- 1
List the nine essential amino acids for humans.
A common memory aid is HILL MTV PT, which stands for histidine, isoleucine, leucine, lysine, methionine, threonine, valine, phenylalanine, and tryptophan.
The nine essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. - 2
Explain what makes an amino acid essential in human nutrition.
An amino acid is essential if the human body cannot make enough of it on its own, so it must be obtained from food. - 3
A student says, "Essential amino acids are more important than nonessential amino acids because the body uses only essential amino acids to build proteins." Explain why this statement is incorrect.
Focus on the meaning of the word essential in nutrition.
The statement is incorrect because the body uses both essential and nonessential amino acids to build proteins. Essential amino acids are called essential because they must come from the diet, not because they are the only amino acids used in proteins. - 4
Classify each amino acid as essential or nonessential for humans: leucine, alanine, valine, glycine, lysine, serine.
Leucine, valine, and lysine are essential amino acids. Alanine, glycine, and serine are nonessential amino acids because the body can make them. - 5
A food label shows that a protein source contains all nine essential amino acids in sufficient amounts. What term is commonly used for this type of protein source?
Think about whether the protein has the full set of essential amino acids.
This type of protein source is commonly called a complete protein because it provides all nine essential amino acids in sufficient amounts. - 6
The table shows whether three foods contain enough lysine and methionine. Food A has enough lysine but not enough methionine. Food B has enough methionine but not enough lysine. Food C has enough lysine and enough methionine. Which food is most likely to be a complete protein based only on this information, and why?
A complete protein must provide all essential amino acids in sufficient amounts.
Food C is most likely to be a complete protein based only on this information because it contains enough of both lysine and methionine. However, the full conclusion would require checking all nine essential amino acids. - 7
Explain why eating rice and beans together can help meet essential amino acid needs better than eating only one of them.
Complementary proteins can make up for amino acids that are limited in one food.
Rice and beans can complement each other because one food may be lower in certain essential amino acids while the other provides more of them. Together, they can supply a more complete amino acid profile. - 8
A person eats enough total calories but gets very little protein. Explain how this could affect the body's ability to build or repair tissues.
If a person gets very little protein, the body may not receive enough essential amino acids to build and repair tissues effectively. This can affect muscles, enzymes, hormones, immune proteins, and other body structures. - 9
Look at this amino acid profile for a plant protein: histidine is adequate, isoleucine is adequate, leucine is adequate, lysine is low, methionine is adequate, phenylalanine is adequate, threonine is adequate, tryptophan is adequate, and valine is adequate. Which essential amino acid is the limiting amino acid?
The limiting amino acid is the essential amino acid in shortest supply.
Lysine is the limiting amino acid because it is the essential amino acid present in the lowest amount relative to the body's needs. - 10
Methionine contains sulfur, while many amino acids do not. Why does this chemical detail not change the fact that methionine is an essential amino acid?
Methionine is essential because humans cannot make enough of it and must get it from food. Its sulfur-containing structure is important chemically, but essential status depends on whether the body can synthesize enough of the amino acid. - 11
A protein supplement lists these amino acids: leucine, isoleucine, valine, lysine, threonine, tryptophan, phenylalanine, methionine, and histidine. Does it include all nine essential amino acids? Explain your answer.
Compare the supplement list to the standard list of the nine essential amino acids.
Yes, it includes all nine essential amino acids. The list contains leucine, isoleucine, valine, lysine, threonine, tryptophan, phenylalanine, methionine, and histidine. - 12
Create a one-sentence study tip that would help a classmate remember why essential amino acids must be included in the diet.
A good study tip could be: Essential amino acids must come from food because the body cannot make enough of them to meet its needs.