ATI LPN

1. How many amino acids are considered indispensable or essential?

• A. 9
• B. 10
• C. 12
• D. 14

Correct Answer: A

Rationale: The correct answer is A: 9. Nine amino acids are considered essential or indispensable because they cannot be synthesized by the body and must be obtained through the diet. These amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Choices B, C, and D are incorrect as the number of essential amino acids is specifically 9, as they are crucial for various bodily functions.

2. Two amino acids are chemically joined by a:

• A. double bond.
• B. hydrogen bond.
• C. carboxyl bond.
• D. peptide bond.

Correct Answer: D

Rationale: The correct answer is D, peptide bond. A peptide bond is formed through a dehydration synthesis reaction between the amine group of one amino acid and the carboxyl group of another amino acid. This bond is crucial in protein synthesis. Choices A, B, and C are incorrect. A double bond involves sharing two pairs of electrons, a hydrogen bond is a weak attraction between a hydrogen atom and an electronegative atom, and a carboxyl bond is not a common term in biochemistry.

3. Amino acids that can be synthesized by the body in sufficient amounts are known as:

• A. indispensable.
• B. dispensable.
• C. simple.
• D. complex.

Correct Answer: B

Rationale: The correct answer is B, 'dispensable.' Dispensable amino acids are those that the body can synthesize in sufficient amounts, so they are not required to be obtained from the diet. Indispensable amino acids, on the other hand, are essential and must be obtained from the diet because the body cannot produce them in sufficient quantities. Choices C and D, 'simple' and 'complex,' are incorrect as they do not accurately describe amino acids in terms of synthesis by the body.

4. An important characteristic of amino acids is that they can:

• A. act as buffers.
• B. facilitate glucose storage.
• C. regulate heartbeat.
• D. control the level of blood cholesterol.

Correct Answer: A

Rationale: The correct answer is A: act as buffers. Amino acids can act as buffers by helping to maintain the pH balance in the body. Choice B is incorrect because amino acids do not primarily facilitate glucose storage. Choice C is incorrect as amino acids do not regulate the heartbeat. Choice D is also incorrect because amino acids do not control the level of blood cholesterol.

5. Which of the following is an example of a protein?

• A. Saline.
• B. Hemoglobin.
• C. Cellulose.
• D. Prostaglandins.

Correct Answer: B

Rationale: Hemoglobin is a protein that carries oxygen in the blood, making it the correct answer. Choice A, Saline, is a salt solution and not a protein. Choice C, Cellulose, is a complex carbohydrate found in the cell walls of plants, not a protein. Choice D, Prostaglandins, are lipid compounds with hormone-like effects, not proteins.