Nokea
Which of the following is NOT a factor affecting the rate of a chemical reaction?
- A. Concentration of reactants
- B. Temperature
- C. Presence of a catalyst
- D. Color of the reaction mixture
Correct Answer: D
Rationale: The color of the reaction mixture is not a factor affecting the rate of a chemical reaction. Factors such as the concentration of reactants, temperature, and the presence of a catalyst can influence the rate of a chemical reaction by affecting the frequency of collisions between reactant molecules and the energy of those collisions. The color of the reaction mixture is a physical property and does not directly impact the kinetics or speed of the reaction process. It is a qualitative observation that does not alter the reaction rate or mechanisms involved.
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What is the process of converting lactic acid back into pyruvate called?
- A. Glycolysis
- B. Gluconeogenesis
- C. Cori cycle
- D. Oxidative phosphorylation
Correct Answer: C
Rationale: A) Glycolysis is the process of breaking down glucose into pyruvate.
B) Gluconeogenesis is the process of synthesizing glucose from non-carbohydrate sources.
C) The Cori cycle is the process by which lactic acid produced by anaerobic metabolism in muscles is transported to the liver and converted back into glucose or pyruvate.
D) Oxidative phosphorylation is the process by which ATP is synthesized using energy derived from the transfer of electrons in the electron transport chain.
How is the muscular system benefited by regular exercise?
- A. Decreasing muscle mass
- B. Improving muscle strength and endurance
- C. Making muscles less flexible
- D. Increasing the risk of muscle tears
Correct Answer: B
Rationale: Regular exercise is beneficial for the muscular system by improving muscle strength and endurance. Exercise helps to build and maintain muscle mass, increase muscle strength, and enhance muscle endurance. It does not decrease muscle mass, make muscles less flexible, or increase the risk of muscle tears when done properly. Therefore, the correct answer is improving muscle strength and endurance, as it aligns with the positive effects of regular exercise on the muscular system.
What is the primary function of the large intestine?
- A. Digesting and absorbing nutrients
- B. Storing and mixing food
- C. Breaking down carbohydrates
- D. Absorbing water and electrolytes
Correct Answer: D
Rationale: The primary function of the large intestine is to absorb water and electrolytes from the indigestible food matter that passes through it. This absorption process aids in the formation of solid waste (feces) before it is excreted from the body. Choices A, B, and C are incorrect because the large intestine does not primarily digest and absorb nutrients, store and mix food, or break down carbohydrates. These functions are primarily carried out by the small intestine.
Which term refers to the condition where a muscle shortens in length while generating force, leading to movement at a joint?
- A. Isometric contraction
- B. Eccentric contraction
- C. Isotonic contraction
- D. Concentric contraction
Correct Answer: D
Rationale: Concentric contraction refers to the condition where a muscle shortens in length while generating force, leading to movement at a joint. This type of contraction is commonly associated with the lifting phase of an exercise where the muscle is actively shortening against resistance. Isometric contraction (Choice A) involves muscle contraction without a change in muscle length, Eccentric contraction (Choice B) involves the muscle lengthening while generating force, and Isotonic contraction (Choice C) refers to muscle contraction against a constant load with a change in muscle length.
Balance the chemical equation: C4H10 + O2 → CO2 + H2O. What is the coefficient for oxygen?
- A. 5
- B. 6
- C. 7
- D. 8
Correct Answer: B
Rationale: To balance the chemical equation, we need to ensure that the number of each type of atom is the same on both sides of the equation. In this case, there are 10 oxygen atoms on the right side (5 in CO2 and 5 in H2O). To balance this, we need to add a coefficient of 6 in front of O2 on the left side, resulting in 6 O2 molecules. This change will give us a total of 12 oxygen atoms on both sides, making the equation balanced. Choice A (5) is incorrect because it does not account for all the oxygen atoms present in the products. Choices C (7) and D (8) are incorrect as they would result in an imbalance in the number of oxygen atoms on both sides of the equation.