Nokea
Photons, the basic unit of light, are:
- A. Charged particles
- B. Packets of energy with wave-particle duality
- C. Electromagnetic waves only
- D. Always absorbed by matter
Correct Answer: B
Rationale: Photons are not charged particles; they are packets of energy that exhibit wave-particle duality, meaning they can behave as both particles and waves. While photons are part of the electromagnetic spectrum, they are not electromagnetic waves themselves but rather discrete energy packets. They are not always absorbed by matter; they can be reflected, transmitted, or scattered.
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What is the study of fungi known as?
- A. Virology
- B. Mycology
- C. Bacteriology
- D. Parasitology
Correct Answer: B
Rationale: Mycology is the correct answer. Mycology is the branch of biology that specifically deals with the study of fungi. Fungi constitute a separate kingdom of organisms that include various forms such as yeasts, molds, and mushrooms. Virology (A) is the study of viruses, while Bacteriology (C) focuses on bacteria. Parasitology (D) is the study of parasites, which may include protozoa, helminths, and some fungi, but it is not solely dedicated to fungi.
Which of the following blood vessels carries oxygenated blood away from the heart?
- A. Pulmonary artery
- B. Aorta
- C. Superior vena cava
- D. Inferior vena cava
Correct Answer: B
Rationale: The aorta is the correct answer because it is the main artery in the body that carries oxygenated blood away from the heart to the rest of the body. The pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation. The superior and inferior vena cava are veins that carry deoxygenated blood from the body back to the heart. Therefore, choices A, C, and D are incorrect as they do not carry oxygenated blood away from the heart.
Which of the following units is used to express concentration as a mass of solute per unit volume of solution?
- A. Molality (m)
- B. Molarity (M)
- C. Weight percent (%)
- D. Parts per million (ppm)
Correct Answer: A
Rationale: Molality (m) is the unit used to express concentration as a mass of solute per unit volume of solution. It is calculated by dividing the mass of solute in grams by the mass of the solvent in kilograms. Molality is preferred over molarity when there are large temperature variations as it is temperature-independent, making it a more accurate measure of concentration. Molarity (B) is the unit used to express concentration as moles of solute per liter of solution, weight percent (C) is the mass of solute per 100 parts of the total mass of the solution, and parts per million (D) is used to express very small concentrations where 1 ppm is equivalent to 1 mg of solute per liter of solution.
What is the balanced chemical equation for the reaction between sodium and chlorine to form sodium chloride?
- A. Na + Cl2 -> NaCl
- B. 2Na + Cl2 -> 2NaCl
- C. Na2 + Cl -> 2NaCl
- D. Na + 2Cl -> NaCl2
Correct Answer: B
Rationale: In a balanced chemical equation, the number of atoms of each element must be the same on both sides of the equation. When sodium (Na) reacts with chlorine (Cl2) to form sodium chloride (NaCl), we need to ensure the equation is balanced. There are 2 chlorine atoms in Cl2; hence, we need 2 sodium atoms on the left side to balance it. Therefore, the balanced chemical equation is 2Na + Cl2 -> 2NaCl. Choice A is incorrect because it does not have the correct coefficients to balance the equation. Choice C is incorrect as it incorrectly represents the formula of sodium. Choice D is incorrect as it forms NaCl2, which is not the correct compound formed in this reaction.
What cellular process ensures the accurate transmission of genetic material during cell division?
- A. Mitosis (somatic cell division)
- B. Meiosis (germ cell division)
- C. Replication (DNA duplication)
- D. Transcription (DNA to RNA conversion)
Correct Answer: A
Rationale: Mitosis is the correct answer. Mitosis is the process by which somatic cells divide to produce two identical daughter cells. During mitosis, the genetic material is accurately replicated and distributed to ensure each daughter cell receives a complete set of chromosomes. This process is crucial for growth, repair, and maintenance of multicellular organisms. Meiosis, on the other hand, is the type of cell division that occurs in germ cells to produce gametes (sperm and egg cells), focusing on genetic diversity through recombination and reduction of chromosome number. Replication is the process of copying DNA to produce an identical copy, essential for cell division but not the specific process ensuring accurate genetic material transmission. Transcription involves copying DNA into RNA, crucial for gene expression but not directly related to the accurate transmission of genetic material during cell division.