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.
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Mrs. Jones's class is conducting an experiment. They will substitute artificial sweetener for sugar in a cookie recipe to determine the effect on the overall color of the baked cookies. Which of the following should be included in the instructions for the experiment?
- A. When preparing the batch that includes artificial sweetener, 20% more water should be included.
- B. The bake temperature should be decreased from 425°F to 400°F.
- C. The batch with artificial sweetener should be baked on a stainless steel sheet.
- D. Ingredient proportions, bake time, bake temperature, and cookie sheet material should all be kept the same between the two batches.
Correct Answer: D
Rationale: To ensure a valid comparison and isolate the impact of the artificial sweetener, the experiment should maintain consistency in all factors except the sugar substitution. By keeping ingredient proportions, bake time, bake temperature, and cookie sheet material the same, any observed differences in the color of the cookies can be attributed to the artificial sweetener rather than other variables. Choices A, B, and C introduce additional variables that could confound the results. Choice A would alter the consistency of the recipe by adjusting the water content, Choice B would introduce a change in baking temperature which could affect the outcome, and Choice C suggests a change in the type of baking sheet used, potentially impacting the baking process and results. Therefore, maintaining consistency in all other factors except for the sugar substitution is crucial for a reliable experiment.
Fill in the blanks in the following sentence: Enzymes are ________ molecules that serve as _______ for certain biological reactions.
- A. complex; suppressors
- B. acidic; triggers
- C. small; targets
- D. large; catalysts
Correct Answer: D
Rationale: Enzymes are large molecules that act as catalysts, accelerating chemical reactions by lowering the activation energy required for the reactions to occur. In the context of biological reactions, enzymes function as catalysts, not suppressors, triggers, or targets. The use of 'large' and 'catalysts' accurately describes the nature and role of enzymes in facilitating biological processes.
What correction should the student make to the hypothesis: Lengthening the string of the pendulum increases the time it takes the ball to make one complete period?
- A. Turn it into an 'if-then' statement.
- B. Change 'will increase' to 'increases.'
- C. Switch the order of the sentence so that the phrase about the period comes first.
- D. No corrections are needed.
Correct Answer: A
Rationale: The correct answer is A. A hypothesis should be structured as an 'if-then' statement for clarity. This format helps to clearly establish the relationship between the variables and the expected outcome. In this case, the student should frame the hypothesis in a way that if a specific action is taken (lengthening the string), then a specific outcome is expected (increasing the time it takes for the ball to make one complete period). 'If-then' statements are fundamental in hypothesis construction as they clearly define the cause and effect relationship being tested. Choice B is incorrect because changing 'will increase' to 'increases' does not address the structural issue of the hypothesis. Choice C is incorrect as switching the order of the sentence does not fundamentally alter the clarity of the hypothesis. Choice D is incorrect as the hypothesis structure can be improved for better understanding and testing, making correction necessary.
Which structure controls the hormones secreted by the pituitary gland?
- A. Hypothalamus
- B. Adrenal gland
- C. Testes
- D. Pancreas
Correct Answer: A
Rationale: The correct answer is A: Hypothalamus. The hypothalamus controls the release of hormones from the pituitary gland. It acts as a master regulator of the endocrine system by producing releasing and inhibiting hormones that influence the secretion of hormones from the pituitary gland. Choice B, the Adrenal gland, is incorrect because while it plays a role in hormone production, it is not responsible for controlling the pituitary gland's hormones. Choice C, the Testes, and Choice D, the Pancreas, are also incorrect as they are not directly involved in controlling the hormones secreted by the pituitary gland.
What function do genes serve in the relationship between parents and offspring?
- A. Genes enable hereditary information to be passed from parents to offspring.
- B. Genes prohibit hereditary information from being passed from parents to offspring.
- C. Genes enable environmental factors to affect parents and offspring.
- D. Genes serve no function in the relationship between parents and offspring.
Correct Answer: A
Rationale: Genes play a crucial role in passing hereditary information from parents to offspring, ensuring the transmission of genetic traits. This process forms the basis of inheritance and genetic continuity between generations. Choice B is incorrect as genes do not prohibit but rather facilitate the transmission of hereditary information. Choice C is incorrect because genes primarily transmit genetic information, while the influence of environmental factors is separate. Choice D is incorrect as genes are fundamental in genetic inheritance and the relationship between parents and offspring.