Nursing Elites

1. How many different types of nucleotides are there in DNA?

• A. one
• B. two
• C. four
• D. eight

Correct answer: C

Rationale: The correct answer is 'C: four.' DNA is composed of four different types of nucleotides: adenine, thymine, guanine, and cytosine. These nucleotides pair up in specific combinations to form the genetic code. Choices 'A: one,' 'B: two,' and 'D: eight' are incorrect because DNA consists of a set of four distinct nucleotides, not one, two, or eight.

2. 72 chromosomes undergo meiosis. How many chromosomes will be in each gamete?

• A. 18
• B. 36
• C. 72
• D. 144

Correct answer: A

Rationale: During meiosis, the number of chromosomes is halved in each gamete. Since 72 chromosomes undergo meiosis, each gamete will contain half of that number, which is 36 chromosomes. Therefore, the correct answer is 18 chromosomes in each gamete. Choice B (36 chromosomes) is incorrect because it represents the total number of chromosomes that undergo meiosis, not the number in each gamete. Choice C (72 chromosomes) is incorrect as it represents the initial number of chromosomes, not the number in each gamete after meiosis. Choice D (144 chromosomes) is incorrect as it doubles the initial number of chromosomes, which is not the outcome of meiosis.

3. Enzymes are typically _ _.

• A. Fats
• B. Proteins
• C. Sugars
• D. Neurons

Correct answer: B

Rationale: Enzymes are typically proteins that act as biological catalysts, speeding up chemical reactions in living organisms. While most enzymes are made of proteins, a few exceptions, known as ribozymes, are made of RNA. Proteins are composed of amino acids arranged in specific sequences that give enzymes their unique shape and functionality. Choice A, 'Fats,' is incorrect as enzymes are not typically composed of fats. Choice C, 'Sugars,' is incorrect as enzymes are not typically composed of sugars. Choice D, 'Neurons,' is incorrect as neurons are a type of cell in the nervous system, not typically associated with enzymes.

4. Cytosine and thymine are known as:

• A. Purines
• B. Pyrimidines
• C. Both
• D. None of the above

Correct answer: B

Rationale: Cytosine and thymine are known as pyrimidines because they have a single carbon ring structure. Purines, on the other hand, have a double-ring structure. Choice A ('Purines') is incorrect because purines have a double-ring structure, unlike cytosine and thymine. Choice C ('Both') is incorrect as it implies they are both purines and pyrimidines, which is not true. Choice D ('None of the above') is incorrect because cytosine and thymine are indeed pyrimidines.

5. How many bones are included in the human skeletal system?

• A. 412
• B. 103
• C. Over 300
• D. 206

Correct answer: D

Rationale: There are 206 bones in the human skeletal system. This includes bones in the skull, spine, ribs, arms, legs, hands, and feet. The correct answer is 206 because that is the standard number of bones in an adult human body. Choices A, B, and C are incorrect as they do not reflect the accurate count of bones in the human skeletal system.

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