proteins are made up of

HESI A2

HESI A2 Chemistry

1. What are proteins made up of?

A. Fatty acids
B. Amino acids
C. Nucleotides
D. Sugars

Correct answer: B

Rationale: Proteins are made up of amino acids. Amino acids are the building blocks of proteins, essential for various biological processes in the body such as enzyme function, transport, and structural support. Fatty acids (Choice A) are components of lipids, not proteins. Nucleotides (Choice C) are the building blocks of nucleic acids like DNA and RNA, not proteins. Sugars (Choice D) are carbohydrates and are not the primary components of proteins.

2. What is the correct electron configuration for lithium?

A. 1sÂ²2sÂ¹
B. 1sÂ²2sÂ²
C. 1sÂ²2sÂ¹2pÂ¹
D. 1sÂ¹2sÂ¹2pÂ²

Correct answer: A

Rationale: The electron configuration for lithium is 1sÂ²2sÂ¹. Lithium has 3 electrons, and the configuration indicates that the first two electrons fill the 1s orbital, while the third electron fills the 2s orbital. Therefore, the correct electron configuration for lithium is 1sÂ²2sÂ¹. Choice B (1sÂ²2sÂ²) is incorrect as it represents the electron configuration for beryllium, not lithium. Choice C (1sÂ²2sÂ¹2pÂ¹) includes the 2p orbital, which is not involved in lithium's electron configuration. Choice D (1sÂ¹2sÂ¹2pÂ²) is incorrect as it does not accurately represent lithium's electron configuration.

3. What does a blood sample with a pH of 3 indicate?

A. It is strongly acidic.
B. It is strongly basic.
C. It is weakly acidic.
D. It is weakly basic.

Correct answer: A

Rationale: A blood pH of 3 is significantly low, indicating a strong acidity level. The normal blood pH range is 7.35 to 7.45; therefore, a pH of 3 is far below the normal range, showing a highly acidic condition in the blood sample. Choice B is incorrect because a pH of 3 is not basic at all. Choice C is incorrect as a pH of 3 is not weakly acidic but strongly acidic. Choice D is wrong as a blood pH of 3 does not indicate a weakly basic condition.

4. What is the term used when an atom gains one or more electrons?

A. Cation
B. Anion
C. Isotope
D. Electron

Correct answer: B

Rationale: When an atom gains electrons, it becomes negatively charged and is called an anion. An anion is formed when an atom gains one or more electrons, leading to an excess of negative charge. Choice A, 'Cation,' is incorrect because a cation is formed when an atom loses electrons, resulting in a positively charged ion. Choice C, 'Isotope,' refers to atoms of the same element with different numbers of neutrons and is not related to gaining electrons. Choice D, 'Electron,' is the particle that an atom gains to become an anion, not the term for the atom itself after gaining electrons.

5. Which best defines the molarity of an aqueous sugar solution?

A. Grams of sugar per milliliter of solution
B. Moles of sugar per milliliter of solution
C. Grams of sugar per liter of solution
D. Moles of sugar per liter of solution

Correct answer: D

Rationale: The molarity of a solution is defined as the number of moles of solute per liter of solvent. In the case of an aqueous sugar solution, the molarity would be expressed as moles of sugar per liter of solution. This is because molarity is a measurement of the concentration of a solute in a solution based on the number of moles present in a given volume of the solution. Therefore, the correct answer is D. Choices A, B, and C are incorrect because the molarity is specifically defined in terms of moles of solute per liter of solution, not in grams per milliliter or grams per liter. Molarity is a unit of concentration that relates the amount of solute to the volume of the solution, not the mass of the solute.