Nokea
Differentiate between the digestive and respiratory systems.
- A. Mouth
- B. Stomach
- C. Small intestine
- D. Lungs
Correct Answer: D
Rationale: The correct answer is D - Lungs. The mouth, stomach, and small intestine are all components of the digestive system, which is responsible for breaking down food into nutrients that the body can absorb. On the other hand, the lungs are part of the respiratory system, which facilitates the exchange of oxygen and carbon dioxide between the body and the environment through breathing. While the digestive system processes food for energy and nutrients, the respiratory system is primarily focused on the exchange of gases necessary for cellular respiration. Choices A, B, and C are incorrect as they are all organs associated with the digestive system and do not pertain to the respiratory system.
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Which of these is NOT a function of the large intestine?
- A. Absorbing water and electrolytes
- B. Producing vitamins
- C. Breaking down fiber
- D. Eliminating waste products
Correct Answer: B
Rationale: A) Absorbing water and electrolytes: The large intestine plays a crucial role in absorbing water and electrolytes from the indigestible food matter that passes through it. This helps in maintaining the body's fluid balance and preventing dehydration. B) Producing vitamins: While the large intestine contains bacteria that can produce some vitamins like vitamin K and certain B vitamins, the primary site for vitamin production is the small intestine and other organs like the liver. Therefore, producing vitamins is not a primary function of the large intestine. C) Breaking down fiber: The large intestine is responsible for breaking down fiber that was not digested in the small intestine. The bacteria in the large intestine ferment fiber, producing short-chain fatty acids that can be used as an energy source by the body. D) Eliminating waste products: One of the main functions of the large intestine is to eliminate waste products, including indigestible food matter, dead cells, and bacteria, from the body in the form of feces. Therefore, the correct answer is B, as producing vitamins is not a primary function of the large intestine.
In physics, what does the term 'terminal velocity' refer to?
- A. Maximum velocity reached by an object in free fall
- B. Velocity when the object is at rest
- C. Instantaneous velocity of an object
- D. Velocity only reached by heavy objects
Correct Answer: A
Rationale: Terminal velocity in physics refers to the maximum velocity achieved by an object in free fall when the force of gravity equals the force of air resistance. At terminal velocity, the object stops accelerating and maintains a constant speed. This occurs when the opposing forces are balanced, leading to no further increase in speed. Choice B is incorrect as velocity when the object is at rest is zero, not at terminal velocity. Choice C is incorrect as instantaneous velocity refers to the velocity at a specific moment in time, not the maximum speed reached in free fall. Choice D is incorrect because terminal velocity is not exclusive to heavy objects; all objects in free fall can reach terminal velocity under the right conditions.
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.
What is the process of breaking down fatty acids into acetyl-CoA, a key molecule in cellular respiration, called?
- A. Beta-oxidation
- B. Lipolysis
- C. Carbohydrate catabolism
- D. Nucleic acid catabolism
Correct Answer: A
Rationale: Beta-oxidation is the correct term for the process of breaking down fatty acids into acetyl-CoA molecules. This essential process takes place in the mitochondria and is a pivotal step in fatty acid metabolism for energy production. Lipolysis, however, refers to the breakdown of fats into fatty acids and glycerol but does not specifically involve the conversion of fatty acids into acetyl-CoA. Carbohydrate catabolism focuses on breaking down carbohydrates into glucose for energy production and is not directly linked to the conversion of fatty acids into acetyl-CoA. Nucleic acid catabolism involves the breakdown of nucleic acids into nucleotides and is not associated with the conversion of fatty acids into acetyl-CoA.
How did life most likely arise on Earth?
- A. From simple organic molecules in a primordial soup
- B. By spontaneous generation from non-living matter
- C. Through the arrival of extraterrestrial life forms
- D. We still don't know for sure
Correct Answer: A
Rationale: The most widely accepted scientific theory for the origin of life on Earth is abiogenesis, which suggests that life arose from simple organic molecules in a primordial soup. This theory is supported by experiments such as the Miller-Urey experiment, which demonstrated that the basic building blocks of life could have formed under early Earth conditions. While there are other hypotheses and ongoing research in this field, the primordial soup theory is currently the most plausible explanation for the origin of life on Earth. Option B, spontaneous generation from non-living matter, has been disproven and is not considered a valid explanation. Option C, the arrival of extraterrestrial life forms, lacks evidence and is not a widely accepted theory. Option D, stating that we still don't know for sure, is true to some extent as the origin of life is a complex topic, but current scientific understanding leans towards abiogenesis from simple organic molecules in a primordial soup.