Nokea
Which of the following quantities do catalysts alter to control the rate of a chemical reaction?
- A. Substrate energy
- B. Activation energy
- C. Inhibitor energy
- D. Promoter energy
Correct Answer: B
Rationale: The correct answer is B: Activation energy. Catalysts function by reducing the activation energy needed for a chemical reaction to proceed. By lowering the activation energy, catalysts facilitate the reaction without being consumed themselves. Substrate energy, inhibitors, and promoters are not directly altered by catalysts in the same way activation energy is. Substrate energy refers to the energy of the reactants, which is not altered by catalysts. Inhibitors increase the activation energy required for a reaction, while promoters enhance the effectiveness of a catalyst but do not represent a quantity altered by catalysts.
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Which organelle provides energy for cellular functions?
- A. Nucleus
- B. Cell membrane
- C. Mitochondria
- D. Cytoplasm
Correct Answer: C
Rationale: The correct answer is C, Mitochondria. Mitochondria are often referred to as the powerhouse of the cell as they produce energy in the form of ATP through cellular respiration. This process is essential for various cellular functions, making mitochondria crucial for energy production within the cell. Choice A, Nucleus, is incorrect as the nucleus is responsible for housing the cell's genetic material and controlling cellular activities but not for energy production. Choice B, Cell membrane, is incorrect as it is primarily involved in maintaining cell integrity and regulating the passage of substances in and out of the cell, not in energy production. Choice D, Cytoplasm, is incorrect as it is the jelly-like substance that fills the cell and is the site of many metabolic pathways, but it is not the specific organelle responsible for energy production.
A substance is only considered acidic if it has a pH less than what?
- A. 12
- B. 9
- C. 7
- D. 4
Correct Answer: C
Rationale: A substance is considered acidic if its pH is less than 7. pH values below 7 indicate acidity, while pH values above 7 indicate alkalinity or basicity. Substances with a pH less than 7 are categorized as acidic, not above it. Therefore, a substance is classified as acidic if its pH is less than 7, making choice C the correct answer. Choices A, B, and D are incorrect because a pH of 12, 9, and 4, respectively, are all above 7, and therefore not indicative of acidity.
Which of the following statements accurately characterizes the relationship between genes and chromosomes?
- A. Each gene contains multiple chromosomes.
- B. Each chromosome contains multiple genes.
- C. Genes and chromosomes are two different things referring to the same entity.
- D. Genes and chromosomes are not interchangeable terms and do not always occur in equal numbers.
Correct Answer: B
Rationale: The correct answer is B: Each chromosome contains multiple genes. Genes, which are segments of DNA, are located on chromosomes and carry hereditary information. Chromosomes contain many genes, indicating that genes are part of the structure of chromosomes. Choice A is incorrect because genes do not contain chromosomes; rather, they are located on chromosomes. Choice C is incorrect as genes and chromosomes are distinct entities with different functions. Choice D is incorrect because genes and chromosomes are related but not in equal numbers; chromosomes contain multiple genes, but the number of genes can vary between chromosomes.
What type of immunity is acquired through vaccination?
- A. Passive natural immunity
- B. Active natural immunity
- C. Active artificial immunity
- D. Passive artificial immunity
Correct Answer: C
Rationale: The correct answer is C, Active artificial immunity. Vaccination introduces a weakened or inactive form of the pathogen to stimulate the immune system, leading to the development of immunity. Active artificial immunity is the result of deliberate exposure to an antigen, such as through vaccination, to produce an immune response. Passive immunity, like receiving pre-formed antibodies, does not involve the immune system's activation. Natural immunity is typically acquired through exposure to the pathogen itself, not through vaccination.
Which of the following describes a responsibility of the integumentary system?
- A. Distributing vital substances, such as nutrients, throughout the body.
- B. Blocking pathogens that cause disease.
- C. Sending leaked fluids from the cardiovascular system back to the blood vessels.
- D. Storing bodily hormones that influence gender traits.
Correct Answer: B
Rationale: The correct responsibility of the integumentary system is to act as a barrier that blocks pathogens from entering the body, thus helping to prevent diseases and infections. This function serves as the first line of defense for the body against external threats. Choices A, C, and D are incorrect. Choice A is a function of the circulatory system, not the integumentary system. Choice C relates to the lymphatic system, not the integumentary system. Choice D involves the endocrine system, not the integumentary system.