Nokea
What type of molecules are enzymes?
- A. Water molecules
- B. Protein molecules
- C. Tripolar molecules
- D. Inorganic molecules
Correct Answer: B
Rationale: The correct answer is B: Protein molecules. Enzymes are biological catalysts made up of proteins. They function by facilitating and speeding up chemical reactions in living organisms. Therefore, enzymes are primarily composed of protein molecules, not water, tripolar, or inorganic molecules. Choice A (Water molecules), Choice C (Tripolar molecules), and Choice D (Inorganic molecules) are incorrect because enzymes are specifically classified as proteins due to their structure and function in biological systems.
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Which of the following is most different from the others?
- A. Thyroid gland
- B. Stomach
- C. Intestines
- D. Pancreas
Correct Answer: B
Rationale: The correct answer is B, 'Stomach.' The stomach is an organ of the digestive system responsible for breaking down food through mechanical and chemical digestion. In contrast, the thyroid, intestines, and pancreas are glands. The thyroid gland regulates metabolism through hormone secretion, the intestines aid in digestion and nutrient absorption, and the pancreas secretes digestive enzymes and hormones. Therefore, the stomach is functionally different from the other options as it is an organ involved in digestion, while the others are glands with specific secretory functions.
Which of the following body systems controls fluid loss, protects deep tissues, and synthesizes vitamin D?
- A. The skeletal system
- B. The muscular system
- C. The lymphatic system
- D. The integumentary system
Correct Answer: D
Rationale: The integumentary system is responsible for controlling fluid loss through sweat, protecting deep tissues as the body's first line of defense, and synthesizing vitamin D when exposed to sunlight. The skin, hair, nails, and associated glands make up the integumentary system, which plays a crucial role in maintaining homeostasis and overall health. The skeletal system (Choice A) provides structural support and protection for internal organs but does not directly control fluid loss, protect deep tissues, or synthesize vitamin D. The muscular system (Choice B) is responsible for movement and stability but is not involved in the functions described. The lymphatic system (Choice C) is primarily responsible for immunity and fluid balance, not the specific functions mentioned in the question.
An atom has 5 protons, 5 neutrons, and 6 electrons. What is the electric charge of this atom?
- A. Neutral
- B. Positive
- C. Negative
- D. Undetermined
Correct Answer: C
Rationale: The correct answer is 'Negative.' An atom becomes negatively charged when it has more electrons than protons. In this case, the atom has 6 electrons and 5 protons, resulting in a net negative charge. Choice A 'Neutral' is incorrect because the atom is not balanced in terms of protons and electrons. Choice B 'Positive' is incorrect because having more electrons than protons results in a negative charge. Choice D 'Undetermined' is incorrect, as the charge can be determined based on the relative number of protons and electrons.
What is the cellular function of cilia and flagella?
- A. Cilia and flagella are responsible for cell movement.
- B. Cilia and flagella synthesize proteins.
- C. Cilia and flagella help protect the cell from its environment.
- D. Cilia and flagella have enzymes that help with digestion.
Correct Answer: A
Rationale: The correct answer is A: Cilia and flagella are responsible for cell movement. Cilia and flagella are specialized structures found on the surface of many types of cells. They are involved in the movement of the cell itself or in moving substances around the cell. This movement helps in various functions such as propulsion, moving fluids, and sensing the environment. Choices B, C, and D are incorrect. Cilia and flagella are not involved in synthesizing proteins, protecting the cell from its environment, or aiding in digestion. Their primary function is related to cell movement and cellular transport.
Which of the following stimulates adaptive immunity?
- A. Peptides
- B. Phagocytes
- C. Prions
- D. Platelets
Correct Answer: C
Rationale: The correct answer is C: Prions. Prions are infectious proteins that can stimulate an adaptive immune response by triggering the production of specific antibodies. Peptides are fragments of proteins and can be processed and presented by antigen-presenting cells to activate T cells, which play a role in adaptive immunity. Phagocytes, such as macrophages, are part of the innate immune system and are involved in engulfing and destroying pathogens, but they do not directly stimulate adaptive immunity. Platelets are primarily involved in blood clotting and are not directly related to stimulating adaptive immunity.