most enzymes are made up of

HESI A2

Biology HESI A2 Practice Exam

1. Most enzymes are made up of what?

A. proteins
B. lipids
C. starches
D. simple sugars

Correct answer: A

Rationale: Most enzymes are made up of proteins. Proteins are large biomolecules composed of amino acids that are vital for the structure and function of enzymes. Enzymes act as catalysts in biochemical reactions, speeding up the rate of chemical reactions in living organisms. They exhibit high specificity and efficiency due to their unique protein structures. Lipids, starches, and simple sugars are not typically the primary components of enzymes, making them incorrect choices.

2. What does Abstain mean?

A. To voluntarily refrain from something
B. To consume something
C. To eat
D. To encourage

Correct answer: A

Rationale: The correct answer is A: 'To voluntarily refrain from something.' Abstain means to choose not to do or have something, especially something you like or enjoy. Choices B, C, and D are incorrect because abstain does not mean to consume something, to eat, or to encourage. It specifically refers to the act of voluntarily refraining from an action or practice.

3. A worker ships 25 boxes each day. Each box contains 3 shipping labels. The inventory has 500 shipping labels. How many days will it take to use the inventory of shipping labels? Round to the nearest whole.

A. 7 days
B. 8 days
C. 20 days
D. 6 days

Correct answer: A

Rationale: To find out how many days it will take to use the 500 shipping labels, multiply the number of labels used per day (25 boxes * 3 labels/box = 75 labels) by the total number of days the inventory will last (500 labels ÷ 75 labels/day = 6.67 days). Rounded to the nearest whole number, it will take 7 days to use the inventory of shipping labels. Choice B (8 days) is incorrect because the calculation yields 6.67 days, which rounds down to 6 days, making it an incorrect answer. Choice C (20 days) and Choice D (6 days) are also incorrect as they are not the nearest whole number to the correct answer of 7 days.

4. When a person finds ________________ in a stressful situation, it helps to breathe deeply.

A. Oneself
B. Yourself
C. Themselves
D. Itself

Correct answer: A

Rationale: In this sentence, 'Oneself' is the correct reflexive pronoun to use when referring back to the singular subject 'a person.' It is important to match the reflexive pronoun with the singular noun. 'Yourself' and 'Themselves' are plural forms and do not agree with the singular subject 'a person.' 'Itself' is used for inanimate objects, not for people. Therefore, 'Oneself' is the most suitable choice in this context.

5. How many neutrons are in an atom of uranium-235?

A. 92
B. 125
C. 143
D. 235

Correct answer: A

Rationale: The correct answer is A: '92'. To determine the number of neutrons in an atom, you subtract the atomic number (number of protons) from the atomic mass number. For uranium-235, the atomic number is 92, and the atomic mass number is 235. Subtracting 92 from 235 gives us 143 neutrons in an atom of uranium-235. Therefore, options B, C, and D are incorrect as they do not represent the correct number of neutrons in an atom of uranium-235.