Nokea
The body's first line of defense against pathogens is the innate immune system. Which of the following is NOT a component of the innate immune system?
- A. Physical barriers like skin and mucous membranes
- B. Phagocytes that engulf and destroy pathogens
- C. Inflammatory response to isolate and contain infection
- D. Production of antibodies specific to a particular pathogen
Correct Answer: D
Rationale: The production of antibodies specific to a particular pathogen is a function of the adaptive immune system, not the innate immune system. The innate immune system provides immediate, non-specific defense mechanisms against pathogens, including physical barriers, phagocytes, and inflammatory responses. Choices A, B, and C are all correct components of the innate immune system. Physical barriers like skin and mucous membranes act as the first line of defense, preventing pathogens from entering the body. Phagocytes are specialized cells that engulf and destroy pathogens, while the inflammatory response helps isolate and contain infections to prevent their spread.
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Which type of isomerism arises due to differences in the arrangement of atoms around a double bond?
- A. Chain isomerism
- B. Functional group isomerism
- C. Cis-trans isomerism
- D. Stereoisomerism
Correct Answer: C
Rationale: Cis-trans isomerism, also known as geometric isomerism, arises due to differences in the arrangement of atoms around a double bond. In cis isomers, similar groups are on the same side of the double bond, while in trans isomers, similar groups are on opposite sides of the double bond. This type of isomerism is a subset of stereoisomerism, which includes all isomers that have the same connectivity but differ in spatial arrangement. Chain isomerism involves differences in the carbon chain arrangement, functional group isomerism involves different functional groups, and stereoisomerism is a broader category that encompasses isomers with the same connectivity but different spatial arrangement.
What is the recommended daily intake of protein for adults to maintain healthy muscle mass?
- A. 0.5 grams per kilogram of body weight
- B. 1 gram per kilogram of body weight
- C. 1.5 grams per kilogram of body weight
- D. 2 grams per kilogram of body weight
Correct Answer: B
Rationale: The recommended daily intake of protein for adults to maintain healthy muscle mass is typically around 1 gram per kilogram of body weight. This amount can vary based on individual factors such as activity level, age, and overall health status. Consuming an adequate amount of protein is essential for muscle repair and growth, as well as overall health and functioning of the body. Choices A, C, and D are incorrect because they suggest protein intake levels that are either too low (A) or unnecessarily high (C and D) for maintaining healthy muscle mass. Excessive protein intake can strain the kidneys and may not provide additional benefits for muscle health beyond the recommended levels.
Which of the following is the main organ responsible for absorbing nutrients?
- A. Stomach
- B. Small intestine
- C. Large intestine
- D. Pancreas
Correct Answer: B
Rationale: The small intestine is the main organ responsible for absorbing nutrients from the food we eat. It is where the majority of digestion and absorption of nutrients such as carbohydrates, proteins, fats, vitamins, and minerals occurs. The inner lining of the small intestine is covered in tiny finger-like projections called villi, which increase the surface area available for nutrient absorption. While the stomach plays a role in breaking down food into smaller particles, the actual absorption of nutrients primarily takes place in the small intestine. The large intestine mainly absorbs water and electrolytes, and the pancreas produces digestive enzymes and hormones but is not primarily responsible for absorbing nutrients.
Which element is used in fluorescent lamps and emits ultraviolet light when excited?
- A. Mercury
- B. Neon
- C. Argon
- D. Krypton
Correct Answer: A
Rationale: Mercury is the correct element used in fluorescent lamps to emit ultraviolet light when excited. When an electric current passes through the mercury vapor inside the lamp, it generates ultraviolet (UV) light. This UV light then excites the phosphors coated on the inner surface of the lamp, causing them to emit visible light. Neon, argon, and krypton are not commonly used in fluorescent lamps for this purpose. Neon is primarily used in neon signs, argon is used in incandescent and fluorescent bulbs for inertia gas, and krypton is mainly used in certain types of specialized light bulbs for its specific properties.
Which of the following is an example of a polymer?
- A. Methane
- B. Ethanol
- C. Polyethylene
- D. Acetic acid
Correct Answer: C
Rationale: The correct answer is C, Polyethylene. Polyethylene is a polymer composed of a large number of repeating ethylene units linked together, forming a long-chain molecule, characteristic of polymers. Methane, ethanol, and acetic acid are small organic molecules that do not demonstrate the repeating unit structure typical of polymers. Therefore, they are not examples of polymers.