Nursing Elites

1. Why are bacteria and blue-green algae often classified together?

• A. Both are gymnosperms.
• B. Both are prokaryotes.
• C. Both are autotrophs.
• D. Both are pathogens.

Correct answer: B

Rationale: Bacteria and blue-green algae (cyanobacteria) are often classified together because they are both prokaryotes. Prokaryotes are unicellular organisms that lack a membrane-bound nucleus and other membrane-bound organelles. This characteristic distinguishes them from eukaryotic organisms, which have these membrane-bound structures. Choice A is incorrect because gymnosperms are seed-producing plants with naked seeds, not bacteria or blue-green algae. Choice C is incorrect because being an autotroph (able to produce its own food) is not a reason for classifying them together. Choice D is incorrect because not all bacteria and blue-green algae are pathogens; many of them are beneficial or neutral to other organisms.

2. Enzymes can _ reactions.

• A. Catalyze
• B. Inhibit
• C. Stop
• D. None of the above

Correct answer: A

Rationale: Enzymes function as catalysts that promote and accelerate chemical reactions in biological systems. They do this by lowering the activation energy required for the reactions to occur, thereby speeding up the process without being consumed in the reaction. Enzymes facilitate reactions rather than inhibiting or stopping them. Therefore, the correct answer is 'Catalyze.' 'Inhibit' and 'Stop' are incorrect because enzymes do not hinder or halt reactions but rather enhance them.

3. What process do cells in the tip of a plant’s root undergo to increase in number?

• A. Meiosis
• B. Cytokinesis
• C. Fractioning
• D. Mitosis

Correct answer: D

Rationale: Cells in the tip of a plant's root undergo the process of mitosis to increase in number. Mitosis is a type of cell division that results in two daughter cells with the same number of chromosomes as the parent cell. This process allows for growth and maintenance of tissues in plants by producing new cells through division. Choice A, Meiosis, is incorrect as meiosis is a type of cell division that reduces the number of chromosomes in cells to produce gametes. Choice B, Cytokinesis, is incorrect as it is the division of the cytoplasm following cell division. Choice C, Fractioning, is not a biological process related to cell division.

4. Which bacteria are spherical in shape?

• A. Clostridia
• B. Bacilli
• C. Spirilla
• D. Cocci

Correct answer: D

Rationale: The correct answer is D, Cocci. Bacteria that are spherical in shape are known as cocci. They can be found in various arrangements such as clusters, chains, or pairs. Examples of cocci bacteria include Staphylococcus aureus and Streptococcus pneumoniae. Choice A, Clostridia, consists of rod-shaped bacteria. Choice B, Bacilli, refers to rod-shaped bacteria as well. Choice C, Spirilla, are spiral-shaped bacteria, not spherical.

5. Which two bases are purines?

• A. Adenine (A)
• B. Cytosine (C)
• C. Thymine (T)
• D. Guanine (G)

Correct answer: A

Rationale: Adenine (A) and guanine (G) are the two bases that are purines. Purines are characterized by a double-ring structure containing two carbon rings, distinguishing them from pyrimidines. Adenine and guanine are purines because they possess this unique double-ring structure. Therefore, choices A and D, adenine and guanine, respectively, are the correct answers. Choices B and C, cytosine and thymine, are pyrimidines and do not exhibit the double-ring structure characteristic of purines.

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