Nokea
Which of the following is a unit of power?
- A. Newton-meter (N·m)
- B. Joule (J)
- C. Watt (W)
- D. Kilogram (kg)
Correct Answer: C
Rationale: The correct answer is C: Watt (W). Power is the rate at which work is done or energy is transferred. The unit of power is the watt (W), named after James Watt, the inventor of the steam engine. A Newton-meter (N·m) is a unit of torque, Joule (J) is a unit of energy, and Kilogram (kg) is a unit of mass, not power. Therefore, choices A, B, and D are incorrect as they represent units of torque, energy, and mass, respectively, and not power.
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What does the innate immune system provide?
- A. Nonspecific, immediate defense against pathogens
- B. Specific, long-term immune response through memory cells
- C. Both (a) and (b)
- D. Neither (a) nor (b)
Correct Answer: A
Rationale: The correct answer is A. The innate immune system provides nonspecific, immediate defense against pathogens. It is the body's first line of defense in responding to infections and does not involve memory cells or specific long-term immune responses like the adaptive immune system. Choice B is incorrect because specific, long-term immune responses through memory cells are characteristics of the adaptive immune system, not the innate immune system. Choice C is incorrect because the innate immune system does not provide specific, long-term immune responses. Choice D is incorrect because the innate immune system does provide an immediate defense against pathogens.
What determines the magnitude of the frictional force acting on a book sliding across a table?
- A. Only the mass of the book
- B. Only the normal force from the table
- C. Both the mass of the book and the normal force from the table
- D. Neither the mass of the book nor the normal force from the table
Correct Answer: C
Rationale: The magnitude of the frictional force acting on the book sliding across a table is determined by both the mass of the book and the normal force from the table. Frictional force is proportional to the normal force (which is influenced by the weight of the book, i.e., its mass) and is affected by the surfaces in contact and other friction-related factors. Therefore, both the mass of the book and the normal force from the table are essential in determining the frictional force experienced by the book during its sliding motion. Choices A, B, and D are incorrect because friction is a result of the interaction between the surfaces and is influenced by both the mass of the object and the normal force acting on it.
Which of the following is NOT a type of vaccine?
- A. Live attenuated vaccine
- B. Toxoid vaccine
- C. Conjugate vaccine
- D. Antibiotic
Correct Answer: D
Rationale: A) Live attenuated vaccine: This type of vaccine contains a weakened form of the virus or bacteria that causes the disease. When administered, it stimulates an immune response without causing the disease itself.
B) Toxoid vaccine: Toxoid vaccines are made from toxins produced by bacteria that have been inactivated. They stimulate the immune system to produce antibodies against the toxin, providing immunity against the disease.
C) Conjugate vaccine: Conjugate vaccines are made by combining a weak antigen with a strong antigen to enhance the immune response. They are commonly used to protect against bacterial infections.
D) Antibiotic: Antibiotics are medications used to treat bacterial infections by killing or inhibiting the growth of bacteria. They are not a type of vaccine but rather a class of antimicrobial drugs.
Therefore, the correct answer is D) Antibiotic, as it is not a type of vaccine.
Which type of RNA carries the genetic code from DNA to ribosomes?
- A. Ribosomal RNA (rRNA)
- B. Transfer RNA (tRNA)
- C. Messenger RNA (mRNA)
- D. Deoxyribonucleic acid (DNA)
Correct Answer: C
Rationale: - Messenger RNA (mRNA) carries the genetic information from DNA in the cell's nucleus to the ribosomes in the cytoplasm, where protein synthesis occurs.
- Ribosomal RNA (rRNA) is a component of the ribosomes where protein synthesis takes place.
- Transfer RNA (tRNA) is responsible for bringing amino acids to the ribosomes during protein synthesis.
- Deoxyribonucleic acid (DNA) is the genetic material that contains the instructions for building and maintaining an organism. DNA is transcribed into mRNA before being translated into proteins.
What is the term for a substance that can act as both a proton donor and a proton acceptor?
- A. Acid
- B. Base
- C. Amphiprotic
- D. Neutral
Correct Answer: C
Rationale: Amphiprotic substances are those that can both donate and accept protons. They possess characteristics of both acids and bases, making them capable of acting as proton donors and proton acceptors. Choices A and B represent substances that are specific to either donating or accepting protons. Choice D does not describe a substance's ability to donate or accept protons since neutrality does not inherently involve proton donation or acceptance.